Cam Chain Tensioner

[malber]

I've read Clymer and done the procedure. I know why you're supposed to do it. I just don't understand the mechanics that are involved since Clymer doesn't really explain that part. So what is it we're doing when we're losening and tightening that bolt? I've heard of it being at its limit. What exactly does that mean (all the way in or all the way out)?

[prometheus578]

Cam chain tensioner pushes on a guide, that pushes agin' the cam chain, taking the slack out of it.
Tensioner has a spring-loaded rod that moves inward against the guide. when the chain has worn excessively, the rod moves out to it's limit... meaning, it can adjust no further. At this point, a new chain is in order.
Operation: The bolt and lock nut. When you loosen that bolt, the rod moves forward, adjusts the chain, and then you tighten the bolt, locking the rod in the new position.
Cam chain tension is done when the timing disk is at the "C" mark. When the crank is at this position, the cams are at their position of least tension on the valves (We had a huge argument concerning this last year) This ensures that, due to valve spring pressure, one of the cams doesn't rotate, causing slack somewhere that wouldn't be adjusted out.
http://www.xs11.com/forum/showthread...k&pagenumber=1

[trbig]

Your cam chain is going up and down your motor to and from the crank sliding on teflon guides. Your tensioner is a spring loaded plunger with a rubberized pad on the end. As your motor runs over time, the chain will slowly stretch. When you release set the screw and nut, it releases the plunger on your tensioner, and the tensioner's spring provides proper pressure on the cam chain guide... thus taking the slop out of the cam chain. You tighten the set screw and nut back up, because at speed, the spring pressure in the plunger couldn't hold back the cam chain as it tries to swing in a circle going from your crank to your cams from centrifigal force and causing the cams or crank to jump a tooth on the chain.

...... Crap... Pro types faster than me... lol


Tod

[SanDiegoMike]

it's what's inside that counts.

The bolt that is on the side of the tensioner case locks a shaft in place that has a spring on one end, and the other end pushes against a cam chain guide inside the engine. The spring allows for the correct amount of tension to be applied to the guide when the adjustment is being made, but the shaft must be locked in place afterwards or else adjustment would be lost once the engine was started which could cause the chain to slip, which would cause cam timing to change which could result in pistons and valves slamming into eachother, etc...
Over time (as in any chain/sprocket mechanism), the chain will strech and need to be adjusted to maintain proper tension and ability to turn sprockets without slipping teeth. It is important that you do this for your bike periodically, and DO NOT OVERTIGHTEN THE BOLT AND LOCKNUT!!! You'll know just by listening to the engine if the cam chain needs adjusting...VERY noisy rattling sound. (DAMHIK)

Hope this helps.

[prometheus578]

Yeah, TRBIG... and I even had time to search for and read an old thread.

[SanDiegoMike]

SIGH...once again PROM gets the answer in before anyone else!

[trbig]

So while I was trying to type and eat lunch... you were just busy copying and pasting... Cheater.






Tod

[malber]

Okay, so if the bolt only holds the tensioner in place, how do you tell when the tensioner is at its limit and the chain needs to be replaced?

[trbig]

You're supposed to be able to hear an audible "Click" when you loosen the set screw and nut... but I adjust mine enough that it never does make that sound. What you can do, is adjust it normally, tighten back up the set screw, then take out the two allen screws holding it to the motor. Be prepared to replace the gasket. With the unit in hand, loosen the set screw again. If it pops down some more in your hand, there's still room to adjust. If it barely moves, or doesn't at all... new chain time. I always push the plunger all the way in and tighten the set screw before installing back in, to make sure it slaps forward good when I re-adjust after installation.

Tod

[skids]

I think that the only way you will hear an audible click is if you take it off, cock it, put it back on, release it.

Here is what I think you do to test the adjustability left in the tensioner:
1 Adjust it as usual.
2 remove the tensioner.
3 measure the length from some reference on the plunger to the housing.
4 release the plunger to let it traval as far as it will go.
5 repeat step 3
6 compare measurements from steps 3 and 5. The difference is what is left in the adjustment (Given that the gasket thickness will be the same when it is reinstalled)

Be aware that wear of the cam chain is not the only cause for loss in the adjustment capacity of the tensioner. The chain slipper is another wearable item, but it requires the removal of the head (I think) to replace it. The chain is the lesser of the two evils when it comes to cost and labor. Don't be too surprised if you gain less than a quarter of an inch when replacing the cam chain.

[tonio116]

Hi everyone, I didnt want to start another thread and I couldnt find an answer on search mode, and I wanted to ask you, I am in the process of finally finish putting my head back on, and I was following the book procedures, right after I install the chain on the camshafts, with the dot (guide) on each cam aligned with the arrow mark on the center cap while the crankshaft being in the T position or TDC, the book instructs to turn the crankshaft to the C position, well if I do it right and all the chain slack is off on the intake side shouldnt the cams move along with the crank? I did this but the cams didnt move at all, am I doing it wrong?

[randy]

tonio116;

Sounds like the cam chain is not on the crank sprocket. I hope you didn't turn it too far like that, you may have bent some valves.

If I were you, I'd remove the chain and sprockets from the cams, turn the crank BACK THE WAY YOU CAME to the T mark. (counterclockwise) to avoid the possibility of doing more damage.

Then jiggle and pull both side of the chain until you feel it hook on the crank. Then you can proceed with the cam chain installation. Right after you get the chain set and tensioned, do a compression test before you go any further. That way you'll know if in fact whether you bent any valves before you button up the motor.

[tonio116]

yes, I didnt go all the way around with the crank so I am hoping I didnt do any damage, but I turned the crank from the T to the C mark and once I saw no tension or movement I stopped, I have the chain on the crank and camshaft sprockets , so should I turn the crank to the C position while applying pressure with finger into the hole for the chain tensioner, or should I just install the tensioner now, I noticed that I have tried it while applying pressure with my finger, and it catches but when apply a bit more force the chain slips, what am I doing wrong?

sorry so many questions but sometimes a little feedback from others comes a long way instead of only depending of the manual, thanks

[TopCatGr58]

Once you get the crank to TDC, and the cams with dots up, and the chain and first set of cam sprocket nuts secured to hold everything in place, THEN install and release the tensioner and lock in position. Your finger isn't strong enough to maintain proper tension on the chain while trying to turn it. This way it will keep it tight and it won't jump any teeth. The manual just says to push in the chain with your finger just to allow you to put the exhaust sprocket bolt in place, but you need to install the tensioner and release and lock in place.

Slowly rotate the engine CW 1 rpm and check your dots, if okay, then rotate to gain acces to the OTHER 2 cam sprocket bolts, intall and torque all 4, then rotate a few more revs stopping at the "C" mark.

Then remove the tensioner, recompress the plunger, lock, reinstall and then re-release to finally set the tension, relock. And then you should be good to go. And then still do a bench/static compression test again to ensure you do have compression before attempting to fire it up!

Good luck, keep at it!
T.C.

[skids]

Pushing the cam tenioner with the finger tip was a waste of time for me. BTW, when you line-up the dots with the arrows on the cam bosses, you might find that a cam is off by half a dot... like the dots are too far apart. It was no problem on the timing on mine. It ran fine.