Author Topic: CB750: Aware of cheap parts -tensioner rubber cracked in 2- Carb boots cracking  (Read 48800 times)

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Offline flybox1

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My primary roller is made from the same material from cyclex.  Its holding up nicely.
'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 Prospect

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Reviving an old thread. I just pulled the engine of my CB 750 to replace the faulty cam chain tensioner. I don't want to make the same mistake twice and buy from a Taiwanese supplier. What is the general consensus regarding where to buy a good tensioner.
Current Bikes

1969 CB750  Sandcast #256
1971 CB750K1
1972 CB750K1
1975 CB400F
1975 GL1000 Goldwing
1954 Harley Davidson Panhead
1957 Harley Davidson Panhead

Toronto Canada

Offline madmtnmotors

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  • Posts: 6,106
  • Sunny Central Florida
What is the general consensus regarding where to buy a good tensioner.

Honda.
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 grcamna2

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  • I love to restore & travel. Keep'em Going Strong !
How have the aftermarket steel ones been running ?
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 Prospect

  • Expert
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  • Posts: 1,171

What is the general consensus regarding where to buy a good tensioner.

Honda.

Just ordered one from Honda. It wasn't much more than the cheap ones.  Lesson learned.
Current Bikes

1969 CB750  Sandcast #256
1971 CB750K1
1972 CB750K1
1975 CB400F
1975 GL1000 Goldwing
1954 Harley Davidson Panhead
1957 Harley Davidson Panhead

Toronto Canada

Offline madmtnmotors

  • When did I get to be a
  • Really Old Timer ...
  • *******
  • Posts: 6,106
  • Sunny Central Florida

What is the general consensus regarding where to buy a good tensioner.

Honda.

Just ordered one from Honda. It wasn't much more than the cheap ones.  Lesson learned.

Amen to that. After sourcing new ones from Honda it was only about $20 more than the aftermarket ones I had used...

and I don't have to tear down the top end before 3000 miles this time!
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

  • Someone took this pic of me before I became a
  • Really Old Timer ...
  • *******
  • Posts: 13,851
  • ...not my choice, I was nicknamed...
    • Getting 'em Back on the Road
I still have the "test" going with the aftermarket and Honda rollers sitting in some used motor oil (halfway up their diameters) to see if anything shows up: no change yet. It started in May last year. Neither one shows any effect.
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 madmtnmotors

  • When did I get to be a
  • Really Old Timer ...
  • *******
  • Posts: 6,106
  • Sunny Central Florida
I still have the "test" going with the aftermarket and Honda rollers sitting in some used motor oil (halfway up their diameters) to see if anything shows up: no change yet. It started in May last year. Neither one shows any effect.

I'd be willing to bet it's the stress from the chain on the rollers more than anything else that contributes to the "cheapo" tensioner failing.
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

  • Someone took this pic of me before I became a
  • Really Old Timer ...
  • *******
  • Posts: 13,851
  • ...not my choice, I was nicknamed...
    • Getting 'em Back on the Road
I still have the "test" going with the aftermarket and Honda rollers sitting in some used motor oil (halfway up their diameters) to see if anything shows up: no change yet. It started in May last year. Neither one shows any effect.

I'd be willing to bet it's the stress from the chain on the rollers more than anything else that contributes to the "cheapo" tensioner failing.

Might be? Their recall notice stated it was due to "..extended exposure to motor oil..." which I can't believe, myself.
What I DID find on every one of the clones was: the notch in the pivot arm that aligns with the tang on the pivot pin had burrs on every one. This prevented the whole arm from freely pivoting as they should. I am beginning to suspect that since none of the engines I rebuilt with them have had any troubles, and since I manually ground/filed/polished this burr off on each one so it would work correctly, this is more likely the cause? I got this habit from not having perfect parts from Honda, either: I even have a tensioner arm of theirs in this test that has a too-tight, frozen, roller.
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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  • Posts: 14,912
  • Bought her new 4/75
How do you compare the rubber used in each? Perhaps it's just that simple??
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline PeWe

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  • Posts: 15,572
  • Bike almost back to the 70's 2015
I still have the "test" going with the aftermarket and Honda rollers sitting in some used motor oil (halfway up their diameters) to see if anything shows up: no change yet. It started in May last year. Neither one shows any effect.

I'd be willing to bet it's the stress from the chain on the rollers more than anything else that contributes to the "cheapo" tensioner failing.
+1
Exposure to oil and heat might help to make the rubber prone to crack when the chain is pressing against the rubber wheel.
That rubber feels different than std Honda, softer. I have the leftovers in my garage together with new Honda tensioner.

I was lucky to find the cracked upper wheel when lifting head. I have probably not noticed it. Maybe metal flakes later on in oil when the upper rubber was completely off, chain against the "hub".
« Last Edit: December 11, 2016, 12:35:07 PM 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 HondaMan

  • Someone took this pic of me before I became a
  • Really Old Timer ...
  • *******
  • Posts: 13,851
  • ...not my choice, I was nicknamed...
    • Getting 'em Back on the Road
I still have the "test" going with the aftermarket and Honda rollers sitting in some used motor oil (halfway up their diameters) to see if anything shows up: no change yet. It started in May last year. Neither one shows any effect.

I'd be willing to bet it's the stress from the chain on the rollers more than anything else that contributes to the "cheapo" tensioner failing.
+1
Exposure to oil and heat might help to make the rubber prone to crack when the chain is pressing against the rubber wheel.
That rubber feels different than std Honda, softer. I have the leftovers in my garage together with new Honda tensioner.

I was lucky to find the cracked upper wheel when lifting head. I have probably not noticed it. Maybe metal flakes later on in oil when the upper rubber was completely off, chain against the "hub".

Yeah, like you say, PeWe: the rubber on the clones is a little bit softer. It feels like it might have less "fiber" in it, or something like that, as it seems to be semi-translucent when held up to a real strong light. The Honda one seems to be more opaque.

There are several other aftermarket ones out there that are made of steel (like the Yosh racing ones) or nylon of some kind. The steel ones were originally reported to have been made to prevent their chipping at constant high RPM in races like Daytona, but were said to be hard on the cam chain itself. That makes sense: the nylon ones came along much later, like in the 1990s, IIRC. At least, I don't remember seeing any of those until then?
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 754

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  • Posts: 29,058
Durometer test for hardness .
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline PeWe

  • Really Old Timer ...
  • *******
  • Posts: 15,572
  • Bike almost back to the 70's 2015
I still have the "test" going with the aftermarket and Honda rollers sitting in some used motor oil (halfway up their diameters) to see if anything shows up: no change yet. It started in May last year. Neither one shows any effect.

I'd be willing to bet it's the stress from the chain on the rollers more than anything else that contributes to the "cheapo" tensioner failing.
+1
Exposure to oil and heat might help to make the rubber prone to crack when the chain is pressing against the rubber wheel.
That rubber feels different than std Honda, softer. I have the leftovers in my garage together with new Honda tensioner.

I was lucky to find the cracked upper wheel when lifting head. I have probably not noticed it. Maybe metal flakes later on in oil when the upper rubber was completely off, chain against the "hub".

Yeah, like you say, PeWe: the rubber on the clones is a little bit softer. It feels like it might have less "fiber" in it, or something like that, as it seems to be semi-translucent when held up to a real strong light. The Honda one seems to be more opaque.

There are several other aftermarket ones out there that are made of steel (like the Yosh racing ones) or nylon of some kind. The steel ones were originally reported to have been made to prevent their chipping at constant high RPM in races like Daytona, but were said to be hard on the cam chain itself. That makes sense: the nylon ones came along much later, like in the 1990s, IIRC. At least, I don't remember seeing any of those until then?
Metal wheels is an alternative too. I tried one setup last season (street bike), the upper wheel with teeth has marks after cam chain. The upper wheel should be better hardened?
I think that I'll go for Honda std this time. The only "problem" is that the rubber hardens during the years and fall into small pieces, found in the oil pump area.
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 HondaMan

  • Someone took this pic of me before I became a
  • Really Old Timer ...
  • *******
  • Posts: 13,851
  • ...not my choice, I was nicknamed...
    • Getting 'em Back on the Road
I still have the "test" going with the aftermarket and Honda rollers sitting in some used motor oil (halfway up their diameters) to see if anything shows up: no change yet. It started in May last year. Neither one shows any effect.

I'd be willing to bet it's the stress from the chain on the rollers more than anything else that contributes to the "cheapo" tensioner failing.
+1
Exposure to oil and heat might help to make the rubber prone to crack when the chain is pressing against the rubber wheel.
That rubber feels different than std Honda, softer. I have the leftovers in my garage together with new Honda tensioner.

I was lucky to find the cracked upper wheel when lifting head. I have probably not noticed it. Maybe metal flakes later on in oil when the upper rubber was completely off, chain against the "hub".

Yeah, like you say, PeWe: the rubber on the clones is a little bit softer. It feels like it might have less "fiber" in it, or something like that, as it seems to be semi-translucent when held up to a real strong light. The Honda one seems to be more opaque.

There are several other aftermarket ones out there that are made of steel (like the Yosh racing ones) or nylon of some kind. The steel ones were originally reported to have been made to prevent their chipping at constant high RPM in races like Daytona, but were said to be hard on the cam chain itself. That makes sense: the nylon ones came along much later, like in the 1990s, IIRC. At least, I don't remember seeing any of those until then?
Metal wheels is an alternative too. I tried one setup last season (street bike), the upper wheel with teeth has marks after cam chain. The upper wheel should be better hardened?
I think that I'll go for Honda std this time. The only "problem" is that the rubber hardens during the years and fall into small pieces, found in the oil pump area.

One thing I have noticed in all Honda's (and other similar bikes) bikes AFTER the CB750 is: the cam chain tensioners' tensioner rollers all have semi-toothed sprockets on them. These teeth do not fully engage the chain links, but they do guide the chain accurately onto the sprockets. They also usually have bearings (needle or ball type) inside as well, instead of the plain bearing found in this SOHC4 design (and in other Honda Twins of the era): the fancy bearings certainly reduce rolling friction and hence, chain wear or roller stress. I fully suspect that if a metal roller with some sort of bearings were employed in these SOHC4 engines for a long period of time (supposing first that it could be properly oiled) that it would increase the wear on the outer edges of the cam chain links because of the drag and imperfect mating. On the Yosh rollers (only a couple, or a few) that I have seen, the rollers show the witness of this crash, like you describe. Making it harder might make the chain suffer more?

A while back, someone was making ones from nylon or Delrin (or something) and selling them on eBay. If the right kind of nylon, and a proper bearing installation was accomplished in the center, I suspect this could be a good substitute, as nylons like Polypenco, teflon, and others have high fibrous strength and are naturally slippery (and oil resistant). Has anyone here tried one of those, and then taken it apart after a while to see how it is doing?

I have about a dozen worn ones, which could supply "parts" for a rebuildable kit of some kind, supposing the nylon version works out well. If so, it is mighty tempting to start making such a kit, like Elan makes oil pump parts.
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 754

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I am thinking some oils affect them. More than others..
Anyone with chunkng or flaking, let us know what oil you are running..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline markreimer

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So the failure has always been the roller rivited into the metal body?

I rebuild my 750 top end a couple months back, maybe 400km on it since. I ordered the large roller from Cycle-X, they list it as genuine "straight from Honda" on their site. I forgot to order the smaller wheel/metal body assembly  :o so just reused that piece. Silly because that's the one that tends to wear more.  :-\ Must've ordered that really late at night, or really early in the morning hah.

Hopefully mine is ok.

I'll also add that I have some of the cheap $45 carb boots (eBay purchase I think) and I've been having a real weird stumble/gurgle when cruising mid-RPM. Just recently noticed at least one of my boots has a huge slash in it running from the end, under the band clamp. I didn't even bother checking the others, just parked the bike and ordered legit Honda ones from Partzilla. Waiting for them to arrive now.

lesson learned....Honda parts only whenever there's the option.

Oh, but unlike others, I haven't had an issue with my cruizin image carb kit for my 350F.. except for the float bowl gaskets, They didn't come close to fitting.

Offline jebon

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I use simple 2x11 or 2x12 O-rings, available everywhere. This issue comes up if you have a pre-1973 cylinder, which does not use the long rubber seals in the studs' holes, and a post-1972 head gasket with the big holes. Otherwise, you can just get the right head gasket with the small holes, instead. ;)

Do you have a good p/n for the head gasket with the smaller holes?

When looking for the gasket (or kits) with the smaller holes, choose those listed as for "1969-1972" engines, as opposed to the others. That's the primary difference between the kits. ;)
I have a pre 72 cylinder and seller sent me a later Vesrah kit with the big holes, saying it was fine to use. Will this work for me or should I get the earlier one with small holes?
"Don't let schooling interfere with your education"
---
CB750 K0 1971

Offline HondaMan

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    • Getting 'em Back on the Road

I use simple 2x11 or 2x12 O-rings, available everywhere. This issue comes up if you have a pre-1973 cylinder, which does not use the long rubber seals in the studs' holes, and a post-1972 head gasket with the big holes. Otherwise, you can just get the right head gasket with the small holes, instead. ;)

Do you have a good p/n for the head gasket with the smaller holes?

When looking for the gasket (or kits) with the smaller holes, choose those listed as for "1969-1972" engines, as opposed to the others. That's the primary difference between the kits. ;)
I have a pre 72 cylinder and seller sent me a later Vesrah kit with the big holes, saying it was fine to use. Will this work for me or should I get the earlier one with small holes?

You can use the one with the larger holes, but I recommend inserting O-rings (2x12 or 2x13) into each of those 8 holes to ensure no oil weepage. PM me with your address if you need some of these: I probably have 100 of them, still. For a while we were getting the "big hole" headgaskets in the Vesrah kits, and when they got smarter (2004 or so) they went back to making an early version (VG-156) and the later version (VG-157) kits.
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 johno

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What a great thread !
I recently purchased some parts from CI and 2 parts in particular stood out to me.
How BAD was the cam tensioner, rubber quality /  wheel roller burred. 🤬. in BIN.
How GOOD were the 65mm pistons.  checked thoroughly , dimensions, ring lands, weights, dome thickness etc nice pistolies.😁🏁👍

Just my 2 cents worth to the topic.
cheers Johno
GRASSHOPPER SOHC HONDAS ARE THE MEANING OF LIFE.

Offline MauiK3

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How did anyone do work on stuff like this before great forums like this one could be joined?
1973 CB 750 K3
10/72 build Z1 Kawasaki

Offline HondaMan

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How did anyone do work on stuff like this before great forums like this one could be joined?

My sentiments, exactly! :)
It was partly the reason my shop became so 'famous' back in the day of these bikes, too. We did it right (inspected by me if I didn't do it myself) every time. The one time we didn't was while I was in Final Exams week and a new hire changed the tranny oil (unsupervised) on a new GT550 Suzy he had bought a month earlier: the new kid drained the oil, didn't put any in, and the store manager, during the mechanic's lunch break, gave the bike back to the customer - who lived 50 miles away! Needless to say, I made the manager pay for a new transmission for that poor guy's bike: I wanted him to replace the bike, but he didn't have the $$.

AFAIK that was the only major mistake my shop ever made.
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