Author Topic: CB750: Aware of cheap parts -tensioner rubber cracked in 2- Carb boots cracking  (Read 48682 times)

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Offline flybox1

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Just received a response from Vintage CB750. They have pulled the product from their website and have put the manufacturer on notice until they can get to the bottom of it. They requested photos, so I sent the ones I posted earlier in this thread along with an offer to return the defective parts to them if they need them.

If you can produce a receipt or order number there's a chance that you might get a refund.

When I reached out to them I made it clear that failure of this component could potentially lead to engine seizure and rider injury or death. They seem to be taking it pretty seriously.
Right on....thanks for that Wilbur.
I wonder if they will contact all who have purchased this part with a notice.  Seems like the right thing to do assuming they've only purchased these 'kits' from this Taiwanese vendor.
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline PeWe

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Mark, thanks for the information about tensioner. I had thoughts about the Taiwan tensioner since the rubber felt softer. I was convinced that the tensioner was tested which it cannot be since we are 2 here that got the upper wheel broken very quick. Max 4000kms.
I do not trust the manual replacing the OEM spring.
 Maybe a harder spring might help on higher rpms and releasing the throttle?

I'm waiting fot the metal rollers I ordered from eBay seller Ryan.
http://www.ebay.co.uk/itm/231576401099?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
I have an old Honda OEM metal "body" to use. I'll see if a vise is enough to rivet it.
I'll re-use the cam chain. Tsubaki Camellia HD chain difficult to find nowadays.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Online grcamna2

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Just received a response from Vintage CB750. They have pulled the product from their website and have put the manufacturer on notice until they can get to the bottom of it. They requested photos, so I sent the ones I posted earlier in this thread along with an offer to return the defective parts to them if they need them.

If you can produce a receipt or order number there's a chance that you might get a refund.

When I reached out to them I made it clear that failure of this component could potentially lead to engine seizure and rider injury or death. They seem to be taking it pretty seriously.
Right on....thanks for that Wilbur.
I wonder if they will contact all who have purchased this part with a notice.  Seems like the right thing to do assuming they've only purchased these 'kits' from this Taiwanese vendor.

Yeah ! Good of you to be proactive on this Wilbur.  :)
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline madmtnmotors

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I do not trust the manual replacing the OEM spring.
 Maybe a harder spring might help on higher rpms and releasing the throttle?

A harder spring would only exert more tension when adjusted. Upon tightening the adjustment bolt the tensioner rod is now fixed in place (with more tension) and there would be no "variable" tension at higher RPM or deceleration if that is what you are trying to describe?
TAMTF...


Wilbur



Projects:
"Evolution": http://forums.sohc4.net/index.php?topic=100352.0
"P.O. Debacle": http://forums.sohc4.net/index.php/topic,126692.msg1441661.html#msg1441661
F2/F3 O-rings: http://forums.sohc4.net/index.php?topic=113672.msg1300721#msg1300721
Cam Tower Studs: https://www.mcmaster.com/#93210a017/=t19sgp
Clean up that nasty harness: http://forums.sohc4.net/index.php?topic=137351.msg1549191#msg1549191
http://forums.sohc4.net/index.php/topic,148188.msg1688494.html#msg1688494
http://forums.sohc4.net/index.php/topic,139544.msg1579364.html#msg1579364
                                          
Charging system diagnosis: http://forums.sohc4.net/index.php?topic=1012.msg8345#msg8345
Get the manuals: http://manuals.sohc4.net/cb750k/
The Dragon: http://forums.sohc4.net/index.php?topic=45183.msg1571675#msg1571675
Headlight Switch: http://forums.sohc4.net/index.php?topic=113986.msg1283236#msg1283236
Branden's leak free top end thread: http://forums.sohc4.net/index.php?topic=107040.0
Engine Lifting Made Easy: http://forums.sohc4.net/index.php/topic,58210.msg1684742.html#msg1684742
                                      http://forums.sohc4.net/index.php/topic,100352.msg1675840.html#msg1675840
Static and Dynamic Timing: http://www.hondachopper.com/garage/carb_info/timing/timing1.html
Airbox Gasket Replacement: http://forums.sohc4.net/index.php/topic,114485.msg1290000.html#msg1290000
"Café" : http://forums.sohc4.net/index.php/topic,84697.msg953814.html#msg953814
PD Carb Choke Linkage: http://forums.sohc4.net/index.php/topic,100352.msg1669248.html#msg1669248
                                    http://forums.sohc4.net/index.php/topic,110931.msg1248354.html#msg1248354
                                    http://forums.sohc4.net/index.php/topic,48858.msg515204.html#msg515204
Follow up on your damn posts: http://forums.sohc4.net/index.php/topic,144305.msg1791605.html#msg1791605
Taiwanese Cam Chain Tensioners:  http://forums.sohc4.net/index.php/topic,155043.msg1774841.html#msg1774841
Gumtwo Seat Cover: http://forums.sohc4.net/index.php/topic,164440.msg1897366.html#msg1897366
Primary Drive: http://forums.sohc4.net/index.php/topic,166063.msg1919278.html#msg1919278
Tank Latch: http://forums.sohc4.net/index.php/topic,165975.msg1919495.html#msg1919495
Shorten your forks: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-shorten-forks-td4042465.html DO NOT CUT THE SPRINGS!
Clutch How To: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-change-and-adjust-a-clutch-SOHC-td4040391.html
Late model K7/K8/F2/F3 front sprocket cover removal: http://forums.sohc4.net/index.php/topic,178428.msg2072279.html#msg2072279
630 to 530 conversion: http://forums.sohc4.net/index.php/topic,180710.msg2094423.html#msg2094423

Sent from my Tandy TRS-80!

Online grcamna2

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I do not trust the manual replacing the OEM spring.
 Maybe a harder spring might help on higher rpms and releasing the throttle?

A harder spring would only exert more tension when adjusted. Upon tightening the adjustment bolt the tensioner rod is now fixed in place (with more tension) and there would be no "variable" tension at higher RPM or deceleration if that is what you are trying to describe?

I agree,as long as that tensioner spring and adjustment shaft are working correctly w/ no 'burrs' or rough spots on the sliding shaft and the spring has sufficient tension as it should(Take apart your tensioner to be sure the sliding shaft is in nice shape and smooth)then you can gently lock down the set-bolt and it keeps constant and steady tension on your cam chain.
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline HondaMan

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I do not trust the manual replacing the OEM spring.
 Maybe a harder spring might help on higher rpms and releasing the throttle?

A harder spring would only exert more tension when adjusted. Upon tightening the adjustment bolt the tensioner rod is now fixed in place (with more tension) and there would be no "variable" tension at higher RPM or deceleration if that is what you are trying to describe?

Honda first tried this "variable tension" approach on the CB350F when it first came out. Within 3 months they recalled all of them, replacing the original hydraulic tensioner (oil-pressure based) with a mechanical one. It turns out, not all the riders were using the right oil viscosity, so the chains were getting very slack in use, and noisy. If you have a 350F with the hydraulic tensioner still in place, it's a rare bird, indeed!
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline HondaMan

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Just received a response from Vintage CB750. They have pulled the product from their website and have put the manufacturer on notice until they can get to the bottom of it. They requested photos, so I sent the ones I posted earlier in this thread along with an offer to return the defective parts to them if they need them.

If you can produce a receipt or order number there's a chance that you might get a refund.

When I reached out to them I made it clear that failure of this component could potentially lead to engine seizure and rider injury or death. They seem to be taking it pretty seriously.

Thanks for doing this: the one I have is from PartsNmore, so maybe I'll ask them, if they turn out to be different from the Honda ones. Vintage CB750 has been pretty responsible, overall. :)
« Last Edit: February 17, 2016, 02:56:02 PM by HondaMan »
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline Jerry Rxman Griffin aka MuthaF'er

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Keep in mind that the tensioner only tenses one side of a stretched or worn out chain. While you may take the slack from that area the chain may be noisier on the sprockets and on the far side.
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline madmtnmotors

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Keep in mind that the tensioner only tenses one side of a stretched or worn out chain. While you may take the slack from that area the chain may be noisier on the sprockets and on the far side.

Especially after the wheels disintegrate!  :o
« Last Edit: February 16, 2016, 06:25:33 PM by madmtnmotors »
TAMTF...


Wilbur



Projects:
"Evolution": http://forums.sohc4.net/index.php?topic=100352.0
"P.O. Debacle": http://forums.sohc4.net/index.php/topic,126692.msg1441661.html#msg1441661
F2/F3 O-rings: http://forums.sohc4.net/index.php?topic=113672.msg1300721#msg1300721
Cam Tower Studs: https://www.mcmaster.com/#93210a017/=t19sgp
Clean up that nasty harness: http://forums.sohc4.net/index.php?topic=137351.msg1549191#msg1549191
http://forums.sohc4.net/index.php/topic,148188.msg1688494.html#msg1688494
http://forums.sohc4.net/index.php/topic,139544.msg1579364.html#msg1579364
                                          
Charging system diagnosis: http://forums.sohc4.net/index.php?topic=1012.msg8345#msg8345
Get the manuals: http://manuals.sohc4.net/cb750k/
The Dragon: http://forums.sohc4.net/index.php?topic=45183.msg1571675#msg1571675
Headlight Switch: http://forums.sohc4.net/index.php?topic=113986.msg1283236#msg1283236
Branden's leak free top end thread: http://forums.sohc4.net/index.php?topic=107040.0
Engine Lifting Made Easy: http://forums.sohc4.net/index.php/topic,58210.msg1684742.html#msg1684742
                                      http://forums.sohc4.net/index.php/topic,100352.msg1675840.html#msg1675840
Static and Dynamic Timing: http://www.hondachopper.com/garage/carb_info/timing/timing1.html
Airbox Gasket Replacement: http://forums.sohc4.net/index.php/topic,114485.msg1290000.html#msg1290000
"Café" : http://forums.sohc4.net/index.php/topic,84697.msg953814.html#msg953814
PD Carb Choke Linkage: http://forums.sohc4.net/index.php/topic,100352.msg1669248.html#msg1669248
                                    http://forums.sohc4.net/index.php/topic,110931.msg1248354.html#msg1248354
                                    http://forums.sohc4.net/index.php/topic,48858.msg515204.html#msg515204
Follow up on your damn posts: http://forums.sohc4.net/index.php/topic,144305.msg1791605.html#msg1791605
Taiwanese Cam Chain Tensioners:  http://forums.sohc4.net/index.php/topic,155043.msg1774841.html#msg1774841
Gumtwo Seat Cover: http://forums.sohc4.net/index.php/topic,164440.msg1897366.html#msg1897366
Primary Drive: http://forums.sohc4.net/index.php/topic,166063.msg1919278.html#msg1919278
Tank Latch: http://forums.sohc4.net/index.php/topic,165975.msg1919495.html#msg1919495
Shorten your forks: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-shorten-forks-td4042465.html DO NOT CUT THE SPRINGS!
Clutch How To: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-change-and-adjust-a-clutch-SOHC-td4040391.html
Late model K7/K8/F2/F3 front sprocket cover removal: http://forums.sohc4.net/index.php/topic,178428.msg2072279.html#msg2072279
630 to 530 conversion: http://forums.sohc4.net/index.php/topic,180710.msg2094423.html#msg2094423

Sent from my Tandy TRS-80!

Offline madmtnmotors

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Well, I received my new Honda tensioner wheels and slider and even the Honda wheels seem quite soft and pliable. I guess I'm just used to dealing with heat and age hardened tensioners that have turned to plastic after nearly 40 years in service. The biggest difference is I will run these Honda tensioners with confidence that they will be better suited for their intended purpose.


Unless PeWe starts another thread about how the Honda tensioners are failing too!  :o  ;)  8)
TAMTF...


Wilbur



Projects:
"Evolution": http://forums.sohc4.net/index.php?topic=100352.0
"P.O. Debacle": http://forums.sohc4.net/index.php/topic,126692.msg1441661.html#msg1441661
F2/F3 O-rings: http://forums.sohc4.net/index.php?topic=113672.msg1300721#msg1300721
Cam Tower Studs: https://www.mcmaster.com/#93210a017/=t19sgp
Clean up that nasty harness: http://forums.sohc4.net/index.php?topic=137351.msg1549191#msg1549191
http://forums.sohc4.net/index.php/topic,148188.msg1688494.html#msg1688494
http://forums.sohc4.net/index.php/topic,139544.msg1579364.html#msg1579364
                                          
Charging system diagnosis: http://forums.sohc4.net/index.php?topic=1012.msg8345#msg8345
Get the manuals: http://manuals.sohc4.net/cb750k/
The Dragon: http://forums.sohc4.net/index.php?topic=45183.msg1571675#msg1571675
Headlight Switch: http://forums.sohc4.net/index.php?topic=113986.msg1283236#msg1283236
Branden's leak free top end thread: http://forums.sohc4.net/index.php?topic=107040.0
Engine Lifting Made Easy: http://forums.sohc4.net/index.php/topic,58210.msg1684742.html#msg1684742
                                      http://forums.sohc4.net/index.php/topic,100352.msg1675840.html#msg1675840
Static and Dynamic Timing: http://www.hondachopper.com/garage/carb_info/timing/timing1.html
Airbox Gasket Replacement: http://forums.sohc4.net/index.php/topic,114485.msg1290000.html#msg1290000
"Café" : http://forums.sohc4.net/index.php/topic,84697.msg953814.html#msg953814
PD Carb Choke Linkage: http://forums.sohc4.net/index.php/topic,100352.msg1669248.html#msg1669248
                                    http://forums.sohc4.net/index.php/topic,110931.msg1248354.html#msg1248354
                                    http://forums.sohc4.net/index.php/topic,48858.msg515204.html#msg515204
Follow up on your damn posts: http://forums.sohc4.net/index.php/topic,144305.msg1791605.html#msg1791605
Taiwanese Cam Chain Tensioners:  http://forums.sohc4.net/index.php/topic,155043.msg1774841.html#msg1774841
Gumtwo Seat Cover: http://forums.sohc4.net/index.php/topic,164440.msg1897366.html#msg1897366
Primary Drive: http://forums.sohc4.net/index.php/topic,166063.msg1919278.html#msg1919278
Tank Latch: http://forums.sohc4.net/index.php/topic,165975.msg1919495.html#msg1919495
Shorten your forks: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-shorten-forks-td4042465.html DO NOT CUT THE SPRINGS!
Clutch How To: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-change-and-adjust-a-clutch-SOHC-td4040391.html
Late model K7/K8/F2/F3 front sprocket cover removal: http://forums.sohc4.net/index.php/topic,178428.msg2072279.html#msg2072279
630 to 530 conversion: http://forums.sohc4.net/index.php/topic,180710.msg2094423.html#msg2094423

Sent from my Tandy TRS-80!

Offline Airborne 82nd

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So who all will be taking their hammer to the rivet since you don't have a hydraulic press?

I have a heavy duty flaring tool that should open wide enough to do this instead of making the tool in the instructions from the maker. If not one could use the head off the flare tool in a vice or large 10 or 12 inch c-clamp  ;)
« Last Edit: February 16, 2016, 10:27:25 PM by Airborne 82nd »

Offline PeWe

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Well, I received my new Honda tensioner wheels and slider and even the Honda wheels seem quite soft and pliable. I guess I'm just used to dealing with heat and age hardened tensioners that have turned to plastic after nearly 40 years in service. The biggest difference is I will run these Honda tensioners with confidence that they will be better suited for their intended purpose.


Unless PeWe starts another thread about how the Honda tensioners are failing too!  :o  ;)  8)
Yes, I have one Honda tensioner with very hard rubber, or is it bakelite?  (I'll use it with metal wheels)
I installed it 1983-84, used bike to 1990, almost 50.000kms (double should probably be ok too when its not race used). It was very hard but still functional when I opened the engine 2012. I have had thoughts to complain and suggest Honda to change the design.
It is not acceptable!! ;)
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline PeWe

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  • Bike almost back to the 70's 2015
Opened the cases today.
No other visible damage inside so far.  Primary chains tensioner is OK, clutch looks OK too.
Oil pan has some debris, must be from the tensioner only when everything else is OK. Oil pump mesh had some too of a kind that should not be there after 5000kms, probably visible here at 4000kms.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline Eydugstr

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Just received a response from Vintage CB750. They have pulled the product from their website and have put the manufacturer on notice until they can get to the bottom of it. They requested photos, so I sent the ones I posted earlier in this thread along with an offer to return the defective parts to them if they need them.

If you can produce a receipt or order number there's a chance that you might get a refund.

When I reached out to them I made it clear that failure of this component could potentially lead to engine seizure and rider injury or death. They seem to be taking it pretty seriously.

TY for posting this.  Definitely a step in the right direction.

Offline przjohn

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I save everything when doing a restoration including the bags new parts came in until the job is 100% finished. After reading this thread I scrambled to find the old cam chain tensioner I had replaced for the current 750F project. Whew, a sigh of relief, it was a Honda unit that went in from David Silver   ;D. I think VintageCB750 did the right thing with the information they got, and for me that is a sign of a good vendor.
« Last Edit: February 17, 2016, 01:41:05 PM by przjohn »
I like poetry, long walks on the beach, and poking at dead things with a stick.

Offline HondaMan

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  • ...not my choice, I was nicknamed...
    • Getting 'em Back on the Road
Well, I got my new Honda tensioners (3) today (2/23/16) from South Sound Honda, and immediately went to compare them to the aftermarket one I bought last Fall from PartsNmore. Pictures below. To be honest, I cannot find ANY differences between them. The fit and finish appears identical, the rubber deflects the very same under the same applied pressure (8 pound weight, a big brick), whether pressed in from the side, pressed against the face of the roller, or twisted (by hand, this test). The holes are identical, within a couple thousandths of each other which I would expect from punched-out metal parts like these.

The only difference I can see between them is: their packaging. The Honda ones come in thicker plastic bags with their characteristic red part number labels while the aftermarket ones come in padded-cell plastic bags, with grease applied on the large roller's bearing (the Honda unit is dry). The slider tensioner is exactly the same part, from all I can tell. Even the little dimples of the rubber mold(s) are identical, except the aftermarket upper roller's dimples are slightly shallower, probably indicating the mold was a different temperature when this one was made.

I am wondering now if the vendor who made the aftermarket part(s) that PeWe got in 2012 was formerly making lesser parts, and recently changed them, or if Honda is using the same parts? Don't know...but I do know that it takes about 10k miles to make these rollers hard, based on experience with these engines, and after that time the rubber starts making tiny chunks out of the upper roller, which usually show up trapped in the oil pump's screen. These are hard as plastic by then, too. I also know from experience that the lower roller will get nicks and chips in it if the cam chain is run very loose for a long time, slapping it at hiway RPM speeds on a steady basis. But, I have never seen one fail, like PeWe's unit did?
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline HondaMan

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More pix.
I don't have a clue what has caused PeWe's roller failure?
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Online grcamna2

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Mark,
How about a test installed in 2) different engines for NOS oem Honda and aftermarket? Who's aftermarket roller is that ?
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline PeWe

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I think that my rubber wheels felt softer than Honda's when isntalling it.
My old Honda tensioner that had almost 10 times more km's were still intact when removing it, rubber transfomed to bakelite. 4 long tourings in Europe (5000-6000kms each).
1st one with an engine that ran very hot in former Jugoslavia. I remember that I could not have my leather boots against the engine cases. Autobahn speed was mostly around 140-180km/h, say 100mph in average thru this part. Austria and Jugoslavia was not made in low speed either. I and my girfriend was close to heaven in a 90 degree corner in the mountains when I had to pass 2 slow going camper cars. The corner was thrown in my face when screeming in 170km/h. 4-1 with nothing inside ???
I used 17 cogs front sprocket that made the engine to rev some extra. Cam was Action Fours SS-1 0.0361" lift (measured), RC836, ported head. Almost same setup as today, except for testing varoius hotter cams.

- When did madmtnmotors buy his tensioner that also was soft and fragile after low miles?
http://forums.sohc4.net/index.php/topic,155043.msg1776359.html#msg1776359

I have new complete Honda tensioner and the metal wheel version that has to be riveted. I reuse old Honda tensioner. Its good to keep the old used stuff.

EDIT: Let the new NOT Honda tensioner soak in motor oil for a while and see how the rubber will feel after a while. ;)
« Last Edit: February 25, 2016, 02:46:42 AM by PeWe »
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline madmtnmotors

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- When did madmtnmotors buy his tensioner that also was soft and fragile after low miles?

I purchased my tensioner in the spring of 2015 from Vintage CB750. I believe I have used a tensioner from Parts-n-More on a different engine, but cannot remember which one! I concur with Mark's observation that the Honda tensioner wheels are also quite soft when new.

Of course, I do not know if Parts-n-More and Vintage CB750 are using the same vendor for their cam chain tensioners. After 1700 miles my Vintage CB750 tensioner looked okay at first glance, but clearly well on it's way to failure:

TAMTF...


Wilbur



Projects:
"Evolution": http://forums.sohc4.net/index.php?topic=100352.0
"P.O. Debacle": http://forums.sohc4.net/index.php/topic,126692.msg1441661.html#msg1441661
F2/F3 O-rings: http://forums.sohc4.net/index.php?topic=113672.msg1300721#msg1300721
Cam Tower Studs: https://www.mcmaster.com/#93210a017/=t19sgp
Clean up that nasty harness: http://forums.sohc4.net/index.php?topic=137351.msg1549191#msg1549191
http://forums.sohc4.net/index.php/topic,148188.msg1688494.html#msg1688494
http://forums.sohc4.net/index.php/topic,139544.msg1579364.html#msg1579364
                                          
Charging system diagnosis: http://forums.sohc4.net/index.php?topic=1012.msg8345#msg8345
Get the manuals: http://manuals.sohc4.net/cb750k/
The Dragon: http://forums.sohc4.net/index.php?topic=45183.msg1571675#msg1571675
Headlight Switch: http://forums.sohc4.net/index.php?topic=113986.msg1283236#msg1283236
Branden's leak free top end thread: http://forums.sohc4.net/index.php?topic=107040.0
Engine Lifting Made Easy: http://forums.sohc4.net/index.php/topic,58210.msg1684742.html#msg1684742
                                      http://forums.sohc4.net/index.php/topic,100352.msg1675840.html#msg1675840
Static and Dynamic Timing: http://www.hondachopper.com/garage/carb_info/timing/timing1.html
Airbox Gasket Replacement: http://forums.sohc4.net/index.php/topic,114485.msg1290000.html#msg1290000
"Café" : http://forums.sohc4.net/index.php/topic,84697.msg953814.html#msg953814
PD Carb Choke Linkage: http://forums.sohc4.net/index.php/topic,100352.msg1669248.html#msg1669248
                                    http://forums.sohc4.net/index.php/topic,110931.msg1248354.html#msg1248354
                                    http://forums.sohc4.net/index.php/topic,48858.msg515204.html#msg515204
Follow up on your damn posts: http://forums.sohc4.net/index.php/topic,144305.msg1791605.html#msg1791605
Taiwanese Cam Chain Tensioners:  http://forums.sohc4.net/index.php/topic,155043.msg1774841.html#msg1774841
Gumtwo Seat Cover: http://forums.sohc4.net/index.php/topic,164440.msg1897366.html#msg1897366
Primary Drive: http://forums.sohc4.net/index.php/topic,166063.msg1919278.html#msg1919278
Tank Latch: http://forums.sohc4.net/index.php/topic,165975.msg1919495.html#msg1919495
Shorten your forks: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-shorten-forks-td4042465.html DO NOT CUT THE SPRINGS!
Clutch How To: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-change-and-adjust-a-clutch-SOHC-td4040391.html
Late model K7/K8/F2/F3 front sprocket cover removal: http://forums.sohc4.net/index.php/topic,178428.msg2072279.html#msg2072279
630 to 530 conversion: http://forums.sohc4.net/index.php/topic,180710.msg2094423.html#msg2094423

Sent from my Tandy TRS-80!

Offline HondaMan

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    • Getting 'em Back on the Road
All this makes me wonder if Honda is using the same vendor today that PartsNmore (and others) are, but their old parts used to be different somehow? All of the Honda ones I have nowadays are well used and hard, having many miles on them.

Does anyone out there have a young (in miles) engine with a Honda tensioner inside, which is being taken apart? (Talk about a long shot...).

It is always true that the engine heat will harden the rubber parts, that's a given. The vulcanizing/curing process that makes the rubber is the tool used to set durometer numbers, within a range, on any given rubber compound.
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Online scottly

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Does anyone out there have a young (in miles) engine with a Honda tensioner inside, which is being taken apart? (Talk about a long shot...).

Actually, it's not really a long shot. ;D I just pulled the tensioner out of a low mileage (5312) K7 motor. It's not nearly as soft as Wilbur's. There are marks on the left side of both rollers; the large roller has the number 51, and 180 degrees from the number is a triangular mark that appears to be a logo. The small roller has 35 with the same logo.
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline madmtnmotors

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All this makes me wonder if Honda is using the same vendor today that PartsNmore (and others) are, but their old parts used to be different somehow?


Mark, you're killing me here. I'm really not very interested in tearing this motor apart again any time soon.  >:(

Keep this up and you'll have me questioning my affinity for these old Hondas!  :o  ;)



Does anyone out there have a young (in miles) engine with a Honda tensioner inside, which is being taken apart? (Talk about a long shot...).

Actually, it's not really a long shot. ;D I just pulled the tensioner out of a low mileage (5312) K7 motor. It's not nearly as soft as Wilbur's. There are marks on the left side of both rollers; the large roller has the number 51, and 180 degrees from the number is a triangular mark that appears to be a logo. The small roller has 35 with the same logo.



I think Mark was talking about a low mileage Honda brand tensioner that had been installed recently.

The new Honda parts do look an awful lot like the parts that came from Vintage CB750.... arrrgghh!

I really didn't want to spring for the steel rollers right now...
TAMTF...


Wilbur



Projects:
"Evolution": http://forums.sohc4.net/index.php?topic=100352.0
"P.O. Debacle": http://forums.sohc4.net/index.php/topic,126692.msg1441661.html#msg1441661
F2/F3 O-rings: http://forums.sohc4.net/index.php?topic=113672.msg1300721#msg1300721
Cam Tower Studs: https://www.mcmaster.com/#93210a017/=t19sgp
Clean up that nasty harness: http://forums.sohc4.net/index.php?topic=137351.msg1549191#msg1549191
http://forums.sohc4.net/index.php/topic,148188.msg1688494.html#msg1688494
http://forums.sohc4.net/index.php/topic,139544.msg1579364.html#msg1579364
                                          
Charging system diagnosis: http://forums.sohc4.net/index.php?topic=1012.msg8345#msg8345
Get the manuals: http://manuals.sohc4.net/cb750k/
The Dragon: http://forums.sohc4.net/index.php?topic=45183.msg1571675#msg1571675
Headlight Switch: http://forums.sohc4.net/index.php?topic=113986.msg1283236#msg1283236
Branden's leak free top end thread: http://forums.sohc4.net/index.php?topic=107040.0
Engine Lifting Made Easy: http://forums.sohc4.net/index.php/topic,58210.msg1684742.html#msg1684742
                                      http://forums.sohc4.net/index.php/topic,100352.msg1675840.html#msg1675840
Static and Dynamic Timing: http://www.hondachopper.com/garage/carb_info/timing/timing1.html
Airbox Gasket Replacement: http://forums.sohc4.net/index.php/topic,114485.msg1290000.html#msg1290000
"Café" : http://forums.sohc4.net/index.php/topic,84697.msg953814.html#msg953814
PD Carb Choke Linkage: http://forums.sohc4.net/index.php/topic,100352.msg1669248.html#msg1669248
                                    http://forums.sohc4.net/index.php/topic,110931.msg1248354.html#msg1248354
                                    http://forums.sohc4.net/index.php/topic,48858.msg515204.html#msg515204
Follow up on your damn posts: http://forums.sohc4.net/index.php/topic,144305.msg1791605.html#msg1791605
Taiwanese Cam Chain Tensioners:  http://forums.sohc4.net/index.php/topic,155043.msg1774841.html#msg1774841
Gumtwo Seat Cover: http://forums.sohc4.net/index.php/topic,164440.msg1897366.html#msg1897366
Primary Drive: http://forums.sohc4.net/index.php/topic,166063.msg1919278.html#msg1919278
Tank Latch: http://forums.sohc4.net/index.php/topic,165975.msg1919495.html#msg1919495
Shorten your forks: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-shorten-forks-td4042465.html DO NOT CUT THE SPRINGS!
Clutch How To: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-change-and-adjust-a-clutch-SOHC-td4040391.html
Late model K7/K8/F2/F3 front sprocket cover removal: http://forums.sohc4.net/index.php/topic,178428.msg2072279.html#msg2072279
630 to 530 conversion: http://forums.sohc4.net/index.php/topic,180710.msg2094423.html#msg2094423

Sent from my Tandy TRS-80!

Offline bwaller

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Is there any chance PartsnMore are selling genuine Honda parts in their own bags? I would doubt Honda would source crap.

Offline madmtnmotors

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I would doubt Honda would source crap.

I'm inclined to think the same thing.
TAMTF...


Wilbur



Projects:
"Evolution": http://forums.sohc4.net/index.php?topic=100352.0
"P.O. Debacle": http://forums.sohc4.net/index.php/topic,126692.msg1441661.html#msg1441661
F2/F3 O-rings: http://forums.sohc4.net/index.php?topic=113672.msg1300721#msg1300721
Cam Tower Studs: https://www.mcmaster.com/#93210a017/=t19sgp
Clean up that nasty harness: http://forums.sohc4.net/index.php?topic=137351.msg1549191#msg1549191
http://forums.sohc4.net/index.php/topic,148188.msg1688494.html#msg1688494
http://forums.sohc4.net/index.php/topic,139544.msg1579364.html#msg1579364
                                          
Charging system diagnosis: http://forums.sohc4.net/index.php?topic=1012.msg8345#msg8345
Get the manuals: http://manuals.sohc4.net/cb750k/
The Dragon: http://forums.sohc4.net/index.php?topic=45183.msg1571675#msg1571675
Headlight Switch: http://forums.sohc4.net/index.php?topic=113986.msg1283236#msg1283236
Branden's leak free top end thread: http://forums.sohc4.net/index.php?topic=107040.0
Engine Lifting Made Easy: http://forums.sohc4.net/index.php/topic,58210.msg1684742.html#msg1684742
                                      http://forums.sohc4.net/index.php/topic,100352.msg1675840.html#msg1675840
Static and Dynamic Timing: http://www.hondachopper.com/garage/carb_info/timing/timing1.html
Airbox Gasket Replacement: http://forums.sohc4.net/index.php/topic,114485.msg1290000.html#msg1290000
"Café" : http://forums.sohc4.net/index.php/topic,84697.msg953814.html#msg953814
PD Carb Choke Linkage: http://forums.sohc4.net/index.php/topic,100352.msg1669248.html#msg1669248
                                    http://forums.sohc4.net/index.php/topic,110931.msg1248354.html#msg1248354
                                    http://forums.sohc4.net/index.php/topic,48858.msg515204.html#msg515204
Follow up on your damn posts: http://forums.sohc4.net/index.php/topic,144305.msg1791605.html#msg1791605
Taiwanese Cam Chain Tensioners:  http://forums.sohc4.net/index.php/topic,155043.msg1774841.html#msg1774841
Gumtwo Seat Cover: http://forums.sohc4.net/index.php/topic,164440.msg1897366.html#msg1897366
Primary Drive: http://forums.sohc4.net/index.php/topic,166063.msg1919278.html#msg1919278
Tank Latch: http://forums.sohc4.net/index.php/topic,165975.msg1919495.html#msg1919495
Shorten your forks: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-shorten-forks-td4042465.html DO NOT CUT THE SPRINGS!
Clutch How To: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-change-and-adjust-a-clutch-SOHC-td4040391.html
Late model K7/K8/F2/F3 front sprocket cover removal: http://forums.sohc4.net/index.php/topic,178428.msg2072279.html#msg2072279
630 to 530 conversion: http://forums.sohc4.net/index.php/topic,180710.msg2094423.html#msg2094423

Sent from my Tandy TRS-80!