Author Topic: Replacing Cam Chain Tensioner?  (Read 2404 times)

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chadheins

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Replacing Cam Chain Tensioner?
« on: September 30, 2008, 04:13:20 PM »
How big of an undertaking is this operation? I've been looking on ebay for a working one and prices are good. Mine is stripped and I don't feel so safe riding it. I suppose it is still always applying tension, but I'd rather be able to lock it in to that tension.
Thanks,
-Chad

Offline Patrick

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Re: Replacing Cam Chain Tensioner?
« Reply #1 on: September 30, 2008, 04:49:19 PM »
What bike?
1970 CB750 K0
1982 VF750S Sabre
1987 VT1100 Shadow
1979 Yamaha XS11
1969 Yamaha DT1B
etc.

fuzzybutt

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Re: Replacing Cam Chain Tensioner?
« Reply #2 on: September 30, 2008, 05:32:08 PM »
the the 750's the motor has to come out and the head and cylinders have to come off.

Offline Steve F

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Re: Replacing Cam Chain Tensioner?
« Reply #3 on: September 30, 2008, 05:49:52 PM »
the the 750's the motor has to come out and the head and cylinders have to come off.
If you're refering to the 750, the spring part of the tensioner is held on to the back side of the motor, just below the carbs with three bolts and is easy to replace or fix, any other engine, I'm not familiar with.  If you have to replace the part that contacts the chain, then yes, you have to pull the top-end of the engine to get to it (again for the 750 engine).

chadheins

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Re: Replacing Cam Chain Tensioner?
« Reply #4 on: September 30, 2008, 06:24:40 PM »
Oops that was dumb of me, it's a '76 CB550K

Offline bryanj

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Re: Replacing Cam Chain Tensioner?
« Reply #5 on: October 01, 2008, 10:38:04 AM »
Head and cylinder need to come off
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chadheins

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Re: Replacing Cam Chain Tensioner?
« Reply #6 on: October 01, 2008, 02:15:38 PM »
I just need to replace the tensioner closest to the carbs, the bow type one. From looking at schematics it seems like with the head off it would be doable. Yes, no?

Offline gregimotis

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Re: Replacing Cam Chain Tensioner?
« Reply #7 on: October 01, 2008, 02:51:24 PM »
I just need to replace the tensioner closest to the carbs, the bow type one. From looking at schematics it seems like with the head off it would be doable. Yes, no?



If you're willing to pull the head, the cylinder isn't much more effort (on a 750)

And then you could drive yourself into the madhouse thinking of all the other things you should do while in there: honing the cylinders, replacing the cam chain, fixing the head gasket leak, replacing the internal tensioner parts, valve lap, etc etc. ;)
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Offline WFO

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Re: Replacing Cam Chain Tensioner?
« Reply #8 on: October 01, 2008, 02:55:29 PM »
I just need to replace the tensioner closest to the carbs, the bow type one. From looking at schematics it seems like with the head off it would be doable. Yes, no?



If you're willing to pull the head, the cylinder isn't much more effort (on a 750)

And then you could drive yourself into the madhouse thinking of all the other things you should do while in there: honing the cylinders, replacing the cam chain, fixing the head gasket leak, replacing the internal tensioner parts, valve lap, etc etc. ;)


Well now that you told him  ;D
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Offline Drewery

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Re: Replacing Cam Chain Tensioner?
« Reply #9 on: October 01, 2008, 04:33:58 PM »
I don't think the tensioner did a lot on those 70 Honda engines anyway. I mean, they sort of work, like you need one in there, sort of, and that's the reason those engines always had such a loud cam chain chatter. Personaly, I wouldn't bother until you have to take the engine apart because of something else catastrophic either next week or in 200,000 miles.
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Offline bryanj

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Re: Replacing Cam Chain Tensioner?
« Reply #10 on: October 02, 2008, 12:32:11 AM »
No, the cylinder needs to be lifted and once you have loosened the nuts on the head it disturbs the base gasket and O rings anyway so they need replacing
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline gregimotis

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Re: Replacing Cam Chain Tensioner?
« Reply #11 on: October 02, 2008, 07:06:56 AM »
I don't think the tensioner did a lot on those 70 Honda engines anyway ... and that's the reason those engines always had such a loud cam chain chatter.



Mine doesn't.  Maybe you aren't adjusting it right?
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Offline bryanj

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Re: Replacing Cam Chain Tensioner?
« Reply #12 on: October 02, 2008, 08:56:02 AM »
I agree, if adjusted right you only get a clatter if the chain is toast
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline ieism

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Re: Replacing Cam Chain Tensioner?
« Reply #13 on: October 02, 2008, 11:31:05 AM »
I can relate to  what Drewery is saying. On my first 550 I thought the cam was so loud (compared to other bikes) that the guide or chain must have been completely gone. I bought a new one to replace, only to find out it didn't make much difference. You have to be patient adjusting it.
If the bolt to the guide is stripped, I would get a new one for sure. It will wear out the camchain faster, and a broken chain is a big problem.

Taking the head off and replacing it is only a few hours work. You only need to lift the cylinder block a bit to get the guide out. So theoretically you don't have to get the cylinders out of the barrels (that saves a lot of work trying to get them back in), but you'll have to see if you still trust the gasket when you lift the block.
I lifted mine, and the gasket looked really new. So I left it and it never leaked.

You also need a torque wrench to put the head back on.   
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Offline Drewery

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Re: Replacing Cam Chain Tensioner?
« Reply #14 on: October 05, 2008, 01:43:32 PM »
I find that if one torques the bolts back to spec they sometimes strip the aluminum. They just dont go back together like when the robots do it the first time. Is it unreasonable to dial back on the torque spec to avoid this? (just a little maybe) I realize it might leak a little oil but still.... Anybody have a suggestion?
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Offline BobbyR

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Re: Replacing Cam Chain Tensioner?
« Reply #15 on: October 05, 2008, 04:19:31 PM »
I find that if one torques the bolts back to spec they sometimes strip the aluminum. They just dont go back together like when the robots do it the first time. Is it unreasonable to dial back on the torque spec to avoid this? (just a little maybe) I realize it might leak a little oil but still.... Anybody have a suggestion?
When you torque a bolt you stretch the bolt which wants to spring back to it;s original length. Old bolts that have been torqued may not stretch as they originally did. If you use a lubricant you can cut back 20% on the torque value. If you want more peace of mind you can use a mild(blue) loctitie as a lubricant which will harden and make the bolt more vibration resistant.
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Offline bryanj

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Re: Replacing Cam Chain Tensioner?
« Reply #16 on: October 05, 2008, 08:47:11 PM »
They aint bolts they are studs with nuts and NO it aint alright to reduce the torque value
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline 754

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Re: Replacing Cam Chain Tensioner?
« Reply #17 on: October 05, 2008, 09:24:35 PM »
A base gasket installed with a thin smear of silicone on each side would likely allow it to lift and be re-used.. but if you glued it you are h :o :oped
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Offline Gregorymoto

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Re: Replacing Cam Chain Tensioner?
« Reply #18 on: October 05, 2008, 09:37:20 PM »
Hay Chad M3 racing has a real nice up grade for like 60 might be less.
Its worth it.
Yep, i have issues with this sort of stuff.