Author Topic: Bummer  (Read 3141 times)

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Offline josherr

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Bummer
« on: December 04, 2016, 10:25:45 AM »







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Offline Old Scrambler

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Re: Bummer
« Reply #1 on: December 04, 2016, 02:45:04 PM »
Painful...............but not a killer ;)  Be sure to solve the oil-supply problem before replacing the parts :)
Dennis in Wisconsin
'64 Triumph Cub & '74 Honda CB750 Bonneville Salt Flats AMA Record Holder (6)
CB750 Classic Bonneville Racer thread - http://forums.sohc4.net/index.php/topic,135473.0.html
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Offline SOHC4 Cafe Racer Fan

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Re: Bummer
« Reply #2 on: December 04, 2016, 04:25:50 PM »
Cripes! Never seen that before.
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Offline 754

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Re: Bummer
« Reply #3 on: December 04, 2016, 04:44:02 PM »
Not so bad... Usually can be fixed for around a hundred bux..
 Better now than in the middle of a long ride..far from home..
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 Medyo Bastos

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Re: Bummer
« Reply #4 on: December 04, 2016, 05:04:22 PM »
It'll still run like that


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Offline 754

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Re: Bummer
« Reply #5 on: December 04, 2016, 05:32:06 PM »
Yeah i did 60 mph over a high mountain pass , for over an hour, with one worse than that..
At least it was worse than that when we tore it down the next day.. And it had gotten louder thru the 4 hr ride that day..
« Last Edit: December 04, 2016, 09:15:50 PM by 754 »
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 bill440cars

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Re: Bummer
« Reply #6 on: December 04, 2016, 05:48:36 PM »







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     There might have been worse things that could have happened, but I'd rather not encounter any of that or the other things it could be.  ;)
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Main Rides: '02 Durango, '71 Swinger & Dad's '93
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Offline Desert-SOHC

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Re: Bummer
« Reply #7 on: December 04, 2016, 06:33:30 PM »
I drove one 60 miles that way, I was in the middle of nowhere.
90 F350 Lariat CS S/C Dually
90 S&S 11SC Cabover Camper
97 FLHTP (under construction)
11 Ranger S/C 2wd

Offline markreimer

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Re: Bummer
« Reply #8 on: December 09, 2016, 08:43:12 PM »
Holy smokes is it cracked in half???


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Offline Don R

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Re: Bummer
« Reply #9 on: December 09, 2016, 09:07:07 PM »
  They are wrong. It won't run like that. And if it would you would be putting more debris in the rest of the motor. it most likely bent at least two valves and hurt the opposite cam tower too. Check the cam tower threads in the head to see if any are pulled.
No matter how many times you paint over a shadow, it's still there.
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Offline 754

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Re: Bummer
« Reply #10 on: December 09, 2016, 10:28:19 PM »
They have often run like that..( not saying you should keep running it) mine was outer end , and worse than that. I was surprised that not much ended up in filter, as 1/8 or more wore of the journal, plus a few cam lobes.
 We usually get a few members a year this happens to.
 Now why would you say the valves could be bent ?
 And why do you think it should affect the other side ?
« Last Edit: December 09, 2016, 10:34:25 PM by 754 »
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 stikman

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Re: Bummer
« Reply #11 on: December 09, 2016, 11:33:28 PM »
The motor I just rebuilt came to me looking like that on the outer end as well.  Cam bearings and a few lobes and rockers were wiped.  Clogged oil jet under that cam tower.  Mine was also seized from sitting with water in a cylinder and required more work.  You can find complete cam/towers/rockers/shafts sets on ebay for fairly cheap.  If your oil jets are clogged, you may just get away with swapping a set like that in and running it.  I'd change the oil at least once after the first brief ride or two around town.
1977 CB750A "High Horse": 836cc, mild porting, custom cam, K5 roundtops, v-stacks...
1973 CB750K D5 plunger frame chopper currently building..

Offline josherr

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Re: Bummer
« Reply #12 on: December 10, 2016, 05:06:15 AM »
Thanks stikman I got this engine for 100 of Craigslist for my 750 build
PO said the cam chain might be broken but ended up being the camshaft ... no worries I'm planning on buying a ape racing kit with all that good stuff (camshaft, pistons , valves etc etc )

I have a spare 72 750 engine and plan on using the cam towers from that
Anyone advise against using the cam towers from 72 to a 75 ? Any big difference ?

Hopefully I remember to take lots of pictures to hopefully start a project thread


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Offline 754

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Re: Bummer
« Reply #13 on: December 10, 2016, 09:24:09 AM »
  Wont be a problem using the 72 stuff.
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 SOHC4 Cafe Racer Fan

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Re: Bummer
« Reply #14 on: December 10, 2016, 09:30:03 AM »
Yep. Everything should swap in.
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Offline Desert-SOHC

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Re: Bummer
« Reply #15 on: December 10, 2016, 04:53:00 PM »
Mine seized and broke on the highway at 75 mph or so, sounded like a REALLY fast BRAP/BRAP 20 or so times with a louder PING!!  Then it ran like crap and would only do 45 mph in 3rd...tops.  I rode it at least 30 miles that way, completely wasted the engine and trans.
90 F350 Lariat CS S/C Dually
90 S&S 11SC Cabover Camper
97 FLHTP (under construction)
11 Ranger S/C 2wd

Offline 754

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Re: Bummer
« Reply #16 on: December 10, 2016, 04:59:33 PM »
 When mine got a lot worse, I arrived at my buddies 4 hrs from home .. was hoping he would come out a hear it. I turned it off , he came out and said, That bike aint going anywhere !  So we cut the frame and fixed it.
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 madmtnmotors

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Re: Bummer
« Reply #17 on: December 10, 2016, 06:06:54 PM »
Now why would you say the valves could be bent ?

You mean after half the cam stops turning and half the valves stop closing and all the pistons are still moving? Sounds like the perfect recipe for bent valves to me...
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 754

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Re: Bummer
« Reply #18 on: December 10, 2016, 06:16:38 PM »
I didnt realize till now, that the cam had broke, thought i was looking at bad scoring..  ...Need new glasses....
 I retract that..it should run comment..
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 madmtnmotors

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Re: Bummer
« Reply #19 on: December 10, 2016, 07:11:49 PM »
I didnt realize till now, that the cam had broke, thought i was looking at bad scoring..  ...Need new glasses....
 I retract that..it should run comment..

LOL, I had not realized it was broken at first either, until markreimer pointed it out and I had to go back and look again myself!  ;)  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 754

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Re: Bummer
« Reply #20 on: December 10, 2016, 07:39:28 PM »
They get way smaller than that if its the outboard one..without breaking..less force on them.
 If the closest one plugged, as it did.. Wonder how the other side looked ?

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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Re: Bummer
« Reply #21 on: December 10, 2016, 08:28:07 PM »
Haha! And here I was really questioning if I understood how this engine worked when you guys said it would still run.


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Offline 754

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Re: Bummer
« Reply #22 on: December 10, 2016, 08:49:55 PM »
Well guys have ridden them home like that..  If the valves didnt cock up...  Pull 2 @plugs  370 cc... The end of cam grinding against the other gets messy.
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 SOHC4 Cafe Racer Fan

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Re: Bummer
« Reply #23 on: December 11, 2016, 01:47:54 AM »
Haha! And here I was really questioning if I understood how this engine worked when you guys said it would still run.


Sent from my iPhone using Tapatalk

I saw the crack and was thinking they were smoking something funny.
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold