Cam chain adjustment, new better method!!!

[xjwmx]

Maybe at least. Makes sense to me, but please shoot it down if it needs it. This pertains to the final version adjuster at least, maybe earlier versions.

Once the lock nut is loose, it's common to be able to turn the adjuster with your fingers. If you can't do that, back it out until you can turn it back in with your fingers. Turn it in with your fingers until you would need a wrench to turn it further and stop. Adjustment complete.

I believe as long as you can easily turn the adjuster with your fingers there's no real pressure of the adjuster on the chain. Turning the adjuster in as far as it will go using only your fingers puts the minimum useful pressure of the adjuster on the chain. With mine adjusted this way, the plunger is about flush with the end, as one adjustment method says it should be, and allows about a mm of movement of the plunger, as another adjustment method says it should be. And, the chain is very quiet. My previous method of adjustment was unique too, trying to get minimum useful pressure on the chain by allowing some rattle cold, which goes away when the engine is warm. The mechanism tightens up when it's warm.

EDIT. I now suggest not using this method. The problem is if the adjuster is clean, it's easy to get it much too tight this way.
Details: http://www.xs650.com/threads/cam-chain-adjustment-rethunk-again.52229/

 

[650performance]

xjwmx describes a method that prevents overtightening, and that's a very good thing. I would add that once the engine is warm you can turn it back in with your fingers and then feel the end of the rod. If you feel a slight "nibble" you're there. Now, this is with a high performance/race engine so perhaps there is some benefit of having slightly more slack to ensure nothing binds up, but I've done the same thing on street XS engines with good results. On the other hand, I've never run an engine tens of thousands of highway miles, so perhaps there would be a bit of extra wear. Don't know ...
However, the absolutely wrong thing is to have it too tight.
Craig

 

[nj1639]

Worth a try.

 

[vdubplate]

I've been reading a lot fo different techniques for tightening the chain. What I haven't been able to understand is how o you know that your in a good spot as far as the chain being tight enough.

 

[weekendrider]

The plugger is flush with the adjuster nut when all is good.

 

[5twins]

Well, not necessarily. It depends on what tensioner parts are mixed and matched. There were no fewer than 5 tensioner assemblies used on the 650 over the years .....

If you combine parts from different assemblies, proper adjustment may not be achieved when the plunger is flush with the end of the adjuster screw. As an example, I switched the copper damper washer on my '78 type D assembly to the so-called upgraded rubber/metal washer that Mike's sells. That new washer is much thicker than the original copper one. If I set the adjuster with the plunger flush, it didn't move which means the chain was set too tight. I had to adjust it so the plunger was inset into the screw about 1/8" to get some in/out movement going.

 

[xjwmx]

Since this came back, I'll mention that I found I couldn't turn my adjuster with my fingers when it was hot. Expansion tightens up the threads maybe. The adjustment with the fingers in the op I made cold. Which is good, because you can do the valves right after.

 

[5twins]

I've always done it on a freshly started cold engine so I could adjust it by hand. I also found on mine that as tight as I could set the adjuster by hand was a good adjustment. I've never mentioned that fact because I never tried it on any other 650 but mine so wasn't sure if it was the norm. Seems it may be.

Some swear you must adjust the chain hot because of expansion. I never have. The way I see it is all the parts expand with heat so the adjustment doesn't change radically. I do check it hot from time to time (after setting it cold) and have never found it to be too tight.

 

[section8joe]

Has anyone else been using this method? It's time for me to tighten my chain and do my valves and I think I'll give it a try.

 

[jefft]

I hope this pans out to be an effective way to adjust chain. Since there are 5 different versions of chain adjusters over the years, which one would you rather use if you were installing a Mikes XS big bore kit? Is there a better one?
jefft

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[pcoumbe]

Well, not necessarily. It depends on what tensioner parts are mixed and matched. There were no fewer than 5 tensioner assemblies used on the 650 over the years .....

If you combine parts from different assemblies, proper adjustment may not be achieved when the plunger is flush with the end of the adjuster screw. As an example, I switched the copper damper washer on my '78 type D assembly to the so-called upgraded rubber/metal washer that Mike's sells. That new washer is much thicker than the original copper one. If I set the adjuster with the plunger flush, it didn't move which means the chain was set too tight. I had to adjust it so the plunger was inset into the screw about 1/8" to get some in/out movement going.

I did the same as you, type D with the rubber/metal damper washer and the result was the same as you say, then I fitted a large fin barrel and piston kit from Mikes where the 6 bolt body of the tensioner no longer applies and only the guts of it screws into the back of the new barrel with exactly the same result, about 1/8" low of being flush

 

[5twins]

I have since upgraded my type D tensioner by installing the guts from the type E style. I did so to gain back the locknut feature. It also brought the plunger back flush with the adjuster screw when set properly. There must be slight length differences in the plunger and/or adjuster screw between the 2 types. The type E was designed for use with the newer, thicker washer.

I like the locknut feature. Without it, there's no way to tell if tightening the cap nut has turned the adjuster screw in with it and changed your setting. Yamaha used a locknut on the 1st three types, did away with it on the 4th, then brought it back on the final version. Apparently they realized the error in their ways and concluded a locknut is best. I agree.

If I had to choose a screw assembly for that big fin cylinder, I would pick the final E type. It uses the best damper washer and has the locknut feature.

 

[section8joe]

I adjusted my cam chain using this method and the plunger doesn't seem to move at all after the adjustment. Is this ok? What are the symptoms of a cam chain tensioner thats too tight? I adjusted the valves after adjusting the cam chain and the bike seems to be running great. I may be just a little paranoid but I figured Id ask.

 

[5twins]

If the rod doesn't move, the chain is too tight.

 

[section8joe]

Ok, I'll have to re-adjust it tomorrow. Thanks for the quick reply.

 

[5twins]

Just loosen the adjuster as the motor idles until the rod moves in and out 1 to 2mm. If you go too loose, it will start rattling like loose valves. If you have it too tight, the plunger won't move. It's easiest to adjust on a cold motor because then you can turn the adjuster by hand without burning your fingers. After you get the motor nice and hot, you can pop the acorn cap off and check for rod movement to insure it hasn't tightened up too much.

 

[section8joe]

My exhaust runs in front of my acorn nut. I have to take the exhaust off to make adjustments. Up until now I've just been using the advise of XSLeo.

With the engine off, turn it over to a point where the plunger is in. Now adjust the tension to get the plunger to be flush with the end of the adjuster.
Now if you want you can start the engine and watch the plunger. It should move in and out 1 or 2 mm With it coming just flush.
Shut it down and put the cap on. Enjoy the ride.
Leo

I just thought I'd give the new method a try.

 

[5twins]

Well, this whole thread pertains to doing the adjustment while the motor is idling. It doesn't apply to adjusting it with the motor off. You'd have to use the method described in the shop manual for adjusting with the motor off. In my opinion, that method just plain sucks. That's why I do it running. I borrowed this method from Yamaha's big singles. I figured if it worked for them it should work for the 650 - and it does.

 

[xjwmx]

Well, this whole thread pertains to doing the adjustment while the motor is idling.

Actually the method I described in the original post is done with the motor off, and cold. Back the adjuster out, turn it back in with fingers only until it becomes very difficult to do, done.

The theory is that when you can't do it by fingers anymore, the spring has first begun to compress: you have the minimum useful amount of pressure on the chain from the adjuster. In other words it barely will not rattle cold. After it heats up apparently the mechanism tightens but since it was at a minimum cold it shouldn't get too tight. The adjustment is done cold partly because hot you can't turn the adjuster easily with your fingers at any point: as if the threads tighten up. On my bike.

As always if this is a fubar idea, point it out.

 

[XSLeo]

It does sound like an easy way to set the tensioner, but I would still check it once warmed up just to see if it did change.
The book method and the way it was mentioned in section8joes post works ok, the warmed up idling method works better.
Leo