(Cam Chain Tensioner) What are these bolts for??????

[Alexxxx]

So continues the saga that is my reoccurring cam chain tensioner issue. And, during my copious research in various service manuals and online websites i have one question? What the holy hell are these bolts for(circled in green in photo)????!!!!! I have read all 236 pages of the Heyes SUZUKI GS & GSX 250, 400 &450 Twins Owners Workshop MAnual as well as all 247pgs of the Suzuki GS400-450 ?77-87 Clymer Service Manual and absolutely nowhere are these two bolts mentioned or even acknowledged. So I?m just curious if they maybe have something to do with the cam chain tensioner guide with which I believe they butt up against????? Could be a possible solution to my problem.

So thanks for reading and if you know what the purpose and function of these two bolts (green circle) is please enlighten me . You knowledge is greatly appreciated.

FYI the bike in question is a 1981 GS450E (current mileage 9000)

 

[Burque73]

I'm pretty sure they hold in a cam chain guide, #5 in this diagram.

 

[bonanzadave]

I actually thought there would be a great tutorial on BassCliffs site. Didn't find one. There is a short blurb here.

http://members.dslextreme.com/users/storagecliff/images/engine_odds-n-ends.html



Edit: Here it is from Mr. bwringer
http://bwringer.com/gs/camchaintens.html

 

[bwringer]

I'm pretty sure they hold in a cam chain guide, #5 in this diagram.

Correctamundo.

 

[Alexxxx]

Thanks for the info everybody. So since those bolts do butt up against the cam chainn guide, if one of the two bolts is backed out to far therefore causing the cam chain guide to be loose against the chain could it cause a sound that mimics a loose cam chain?

 

[Gorminrider]

So since those bolts do butt up against the cam chainn guide....

No,It doesn't have anything to do with the cam-chain tensioner . . It's just an extra pad they added. It's not adjustable.There's another one in the top of valve cover...you can try to wiggle them if you like to see if they are loose( but they never are..) If they were making noise,or wearing badly it would be your cam chain slapping them and that takes you back to the tensioner, not these pads.

 

[Alexxxx]

Okay so i think my cam chain tensioner is a piece of crap, because i have taken it off and reset it about 4 times now and right when i think i have the slapping/clicking sound resolved, its back. So i have attached a video of the sound I?m referring to which to me sounds like a loose cam chain slapping around since the slapping sound increases when i roll on the throttle, which is indicative of a faulty CCT. Pls let me know your thoughts oh wise ones much appreciated !! The bike has only 9000 original miles on it so why the heck the CCT is failing at this point says to me a recall should have been done when the bike was put into production in 1981. But whatever. And sorry for the crappy video quality i did the best i could .

 

[Guest]

Doesn't sound like the CCT to me. Valve adjustment, cam timing, cam cap bolts, piston slap - lots of other possibilities, but that sounds like a valve out of spec to me.

Unless you've had the bike for the last 36 years, the motor could be any mileage. My '82 has a motor, frame and speedo from three different bikes. And the motor is an amalgamation of early '80s parts.

Assumptions are the bane of diagnosis.

 

[Steve]

One other thing to be aware of: too many times, part of the instructions for installing the cam chain tensioner is overlooked.

You might have seen instructions somewhere else, but here you go, anyway.

1. Loosen the locknut and the set screw.
2. Take the plunger out, inspect the taper on the inner end. If there is a divot, file or grind the end so it is smooth.
3. Hold the tensioner so you can push the plunger IN. You will need to rotate the large knurled knob to push the plunger in.
4. When the plunger is fully IN, turn the set screw to lock it in place.
5. Install the tensioner to the cylinder block, using a new gasket.
6. Loosen the set screw, you should hear the plunger extend.
7. Turn the set screw IN until it stops, then back it out 1/4 to 1/2 turn, NO MORE.
8. Holding the set screw in that position, tighten the locknut to hold it in place.

The second part of #7 is what frequently gets overlooked. If you don't back off the set screw, the plunger will not be able to move to do its job.

Just watched the video, I didn't hear anything really nasty, certainly not any camm chain slap, but to answer your question, if one or both of those bolts holding the chain guide were loose, yes, it's possible for the chain to rub along the guide, causing a bit of extra noise. I would think it would be more of a rubbing noise, but definitely a bit more noise.

.

 

[Gorminrider]

^^^ Yes, sure sounds like valves I want to say "tappets" but I think that only applies to screw adjusters not shims like yours. One valve sounds out of whack.

....but heres a clip of chain noise . It's "chainier". and from a car but Likely others online

http://forums.vwvortex.com/showthread.php?1127339

 

[Guest]

^^^ Yes, sure sounds like valves I want to say "tappets" but I think that only applies to screw adjusters not shims like yours. One valve sounds out of whack.

A tappet is [British for] a cam follower. In the case of a screw adjust motor, the rocker is the tappet, or at least the shoe that contacts the cam.

In this case it sounds like the adjustment has gone from tapping into whack[ing]. It's a mite unusual, as the normal course is to get tighter, which is why I suspected a loose cam cap. Sometimes people remove the cams to change shims and leave them loose or stripped.

Speaking of which, maybe the OP has yet to hear of the ZTM - zip tie method - of shim switching; I figured that by now it deserved an acronym. You'll never go back; soooo easy.

Another source of tapping sounds can be a loose exhaust pipe, but this seems too regular for that. I remember having a sound like that on an old VW motor when a carb jet fell down into the motor and befriended a piston. If the motor clunks at some point in rotation with the plugs out, that may be it.

 

[Burque73]

I read somewhere if you dont find TDC when you R&R the "CCT" you may be SOL as the chain can jump a tooth on the cam sprockets throwing the timing off. Just wondering if valve to piston contact is happening.
Personally, I have pulled and rebuilt the tensioner without opening up the cam cover to verify TDC and been fine, luckily.

 

[Guest]

I read somewhere if you dont find TDC when you R&R the "CCT" you may be SOL as the chain can jump a tooth on the cam sprockets throwing the timing off. Just wondering if valve to piston contact is happening.
Personally, I have pulled and rebuilt the tensioner without opening up the cam cover to verify TDC and been fine, luckily.

On installation, the RHS piston is at TDC and firing position is established then. Afterwards, the RHS piston can be at TDC and on the off stroke. Quite what would happen if you're 360 degrees off of firing and the CCT is removed I don't know. I've just put my finger over the plug hole while turning the crank so I know which stroke I'm on.

On a Four, there are twice as many valves so cam kickback isn't as much of a problem, but it's still wise to go to the position in the sequence for assembly.

Valve to piston contact is usually more than just a light tapping. More like a clank and no more rotation.

 

[Gorminrider]

Quick question for JP or anyone following the thread:

Is it possible on any of our bikes to be just a tooth "off" at the camchain-at-sprocket timing and NOT have interference...? I had to reset the cams per chain and timing on one GSX400 and was not sure after setting it correctly if the bike had previously been running "one off" (and I'm too lazy to go out and find out the hard way

 

[Guest]

While the cams are in basically the same place on a GSX400 as a GS450, the actual valves are at a very different angle. Thus, they have much less chance of tangling with each other; how much clearance to the piston is an unknown but in general the ability to avoid overrev damage from valve float favors the 4 valve design.

On a 2 valve hemi, the intake valve is moving out towards the exhaust valve still heading home. Thus, if the intake is early by enough there will be interference. Single cam designs avoid this by default, but twin cams rely on the drive system. OTOH, single overhead cams place the cam in the worst spot- right over the top of the combustion chamber, which isn't so bad if you have water cooling.

You can often get away with one tooth off, depending upon which way, which cam and which motor.

 

[Gorminrider]

aha-so I got away with it!--my incident -the cam chain took a leap (involving a valve adjuster nut come adrift) and the bike merely coasted to a stop without any particular noise I remember... after a ride-of-shame in a pickup home, reset cam chain, and it has been going ever since.

 

[Alexxxx]

Thanks All for the input . However, when I did a valve job I checked the timing not was good checked the teeth n there were 18pins between 2&3 . So that's all good . And yes TDC was where I was at . So the only thing I can think that's causing that sound is that I had to leave the RIGHT EXHAUST VALVE CLEARANCE a bit large due to lack of variety of shimm sizes . So al of the rest of the VALVE clearances are within .03-.08mm except the R EX which is at .102 mm. But I was under the impression that leaving the exhaust a bit wide would be okay ?

 

[Nessism]

Yes, .102mm is fine. The KZ1000 engine, which was the "inspiration" for Suzuki when they created the GS engines, runs .05 - .15mm.

 

[Alexxxx]

Yes, .102mm is fine. The KZ1000 engine, which was the "inspiration" for Suzuki when they created the GS engines, runs .05 - .15mm.

Then what is the cause of the sound ?

 

[Gorminrider]

Then what is the cause of the sound ?

is that I had to leave the RIGHT EXHAUST VALVE CLEARANCE a bit large due to lack of variety of shimm sizes . So al of the rest of the VALVE clearances are within .03-.08mm except the R EX which is at .102 mm. But I was under the impression that leaving the exhaust a bit wide would be okay ?

With valve play, I to stay WITHIN the manual's parameters......I'd try get a shim that does that.
Or read more like this
http://dannysengineportal.com/valve-lash-setting-and-adjustment/