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Author Topic: Exhaust Cam Chain  (Read 1691 times)

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Offline eschatz

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Exhaust Cam Chain
« on: May 06, 2011, 07:22:41 AM »
I'm having trouble getting the exhaust cam chain on the cam. I have taken the sprocket off of the cam and slipped the chain over the sprocket. I've got the tensioner as tight as I possibly can. However, I can't get the sprocket on the cam now. Is there some kind of trick to this. The local guru said that he remembers taking the tensioner completely off to put it on but I'm pretty sure I wont be able to get the tensioner back in the jugs if I pull it out. I'm not in the mood to pull all of that back apart and start all over with putting the pistons back in the jugs.

Any tips or tricks?

Cb750
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Offline GammaFlat

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Re: Exhaust Cam Chain
« Reply #1 on: May 06, 2011, 07:29:20 AM »
By "remove tensioner", I think your adviser means, remove the external parts on the backside of the jugs to remove all tension (it has the spring on it). 
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Offline MCRider

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Re: Exhaust Cam Chain
« Reply #2 on: May 06, 2011, 07:37:43 AM »
Quote from: eschatz on May 06, 2011, 07:22:41 AM
I'm having trouble getting the exhaust cam chain on the cam. I have taken the sprocket off of the cam and slipped the chain over the sprocket. I've got the tensioner as tight as I possibly can. However, I can't get the sprocket on the cam now. Is there some kind of trick to this. The local guru said that he remembers taking the tensioner completely off to put it on but I'm pretty sure I wont be able to get the tensioner back in the jugs if I pull it out. I'm not in the mood to pull all of that back apart and start all over with putting the pistons back in the jugs.

Any tips or tricks?

Cb750
The tensioner should be in place and as loose as possible. Maybe that's what you meant but you said tight. You would remove the tensioner from the back side of the cylinder, push the plunger into the housing and tighten the hold bolt down. Reinstall the tensioner. There should be no issue here, removing/replacing the tensioner, setting the chain, etc. all routine items. Something is not right.

Other than that, its just a matter of setting the cam sprocket. The cam should be down in the bearing holders, you say you're getting the chain on the sprocket, so that's not an issue.

While pulling up on the chain, rotate the crank 1/2 turn or so. There may be a link doubled up on the bottom of the crank sprocket.

PS: Not sure what you mean by "exhaust cam chain". There is only one chain and it runs one cam which is both intake and exhaust.
« Last Edit: May 06, 2011, 07:40:54 AM by MCRider »
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Offline lone*X

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Re: Exhaust Cam Chain
« Reply #3 on: May 06, 2011, 07:49:01 AM »
Maybe it a DOHC?
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Lone*X  ( Don )

75 CB550K1  
VTX1800C for two up cruisin.
Several others have come and gone but whose keeping track.
52 years on two wheels and counting.....
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Offline MCRider

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Re: Exhaust Cam Chain
« Reply #4 on: May 06, 2011, 07:56:22 AM »
Quote from: lone*X on May 06, 2011, 07:49:01 AM
Maybe it a DOHC?
Oops, could be. Still just one chain, but he could be struggling with the ex cam. Out of my comfort zone.
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1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Offline eschatz

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Re: Exhaust Cam Chain
« Reply #5 on: May 06, 2011, 08:22:53 AM »
I guess I'm not following you.  My tensioner exerts pressure when it's not bolted down.  If I remove the bolts from the back of the jugs it will try to push against the chain.   When I push against the tensioner and then tighten it down I can force it into it's slimmist position (most chain slack) however, that's not enough to get the sprocket (with the chain on) over the cam to bolt it on.  It has about a mm to go.  When I had the sprocket bolted to the cam and tried to get the chain on that way I got all of the links on except maybe 3.  I was tempted to just turn the crank and pop it on but if I broke the chain I would probably crap my pants and die. 

You got me on the DOHC.  I must confess. Cb750c.  I knew this forum was full of smart bike owners though.  That's why I posted on here.
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Offline lone*X

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Re: Exhaust Cam Chain
« Reply #6 on: May 06, 2011, 08:35:56 AM »
The 750c is for Custom and is a Dual Over Head Cam (DOHC).  They started production in 1978.  Yours must be a 1978 or newer.  This is the Single Over Head Cam (SOHC) forum and the guys here really know their stuff but yours is a different animal.  Maybe if this thread were moved to the "Other Bikes" forum on this site someone would pipe in that is into the DOHC's.

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Lone*X  ( Don )

75 CB550K1  
VTX1800C for two up cruisin.
Several others have come and gone but whose keeping track.
52 years on two wheels and counting.....
"The best safety feature of any motorcycle is the one God put between your ears.  It's also the least utilized"

Offline madmtnmotors

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Re: Exhaust Cam Chain
« Reply #7 on: May 06, 2011, 09:03:39 AM »
Quote from: lone*X on May 06, 2011, 08:35:56 AM
The 750c is for Custom and is a Dual Over Head Cam (DOHC).  They started production in 1978.  Yours must be a 1978 or newer.  This is the Single Over Head Cam (SOHC) forum and the guys here really know their stuff but yours is a different animal.  Maybe if this thread were moved to the "Other Bikes" forum on this site someone would pipe in that is into the DOHC's.




DOHC 750's production run began in 1979. All three of my 78' CB750's only have one cam each...

Correction, production may have begun in 78' for the 79' model year.
« Last Edit: May 06, 2011, 09:05:16 AM by madmtnmotors »
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Offline lone*X

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Re: Exhaust Cam Chain
« Reply #8 on: May 06, 2011, 09:13:37 AM »
Yes, I stand corrected.  I should read my own posts I guess.
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Lone*X  ( Don )

75 CB550K1  
VTX1800C for two up cruisin.
Several others have come and gone but whose keeping track.
52 years on two wheels and counting.....
"The best safety feature of any motorcycle is the one God put between your ears.  It's also the least utilized"

Offline eschatz

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Re: Exhaust Cam Chain
« Reply #9 on: May 06, 2011, 03:19:19 PM »
Ok, so here's what I did. I put all of the bearing caps on and tightened them down. That gave me the clearance to get the sprocket on. I love the "I solved the puzzle" feeling!
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