Hey all,

I finally collected all my shims for the valve adjustment on my bike. Last Saturday I put them in and reinstalled the cams and sprockets. Set the timing chain, and everything looked good. Had to wait to check it until I got the tensioner installed. Found a gasket at the local dealer, so after cleaning off the old gasket, on goes the tensioner.

Unfortunately, as I turned it counter clockwise to check the timing and make sure it turned smoothly, it stopped turning just before coming back to TDC. I didn't want to force it, obviously, but it stopped hard enough that with some extra pressure, I couldn't keep it going. I tried turning it clockwise and it stopped at almost the same place. There is about 10 degrees difference between the two locations. So, it won't turn a full rotation.

Also, it feels really tight. Not like it did when I started this job.

Any ideas? All my shims are thinner than the previous shims. Could I have done something to cause a valve to stick out into the cylinder? Stopping the piston from fully extending?

The only problem that I had when doing the adjustment was that the forward chain guide kind of came out. Not all the way, but it was loose in there, so I fiddled with it until it found a comfortable spot, then I slid the "head" into its notch and didn't think anything of it.

For what its worth, the tensioner seemed tight. Much tighter than it was when I started. Could that be an indication of something? I'd say it only extended about half as far as it did before. Can the chain get messed up in the engine? It looks fine on the cam sprockets. It never dropped into the engine. I had it attached to the frame after I removed the cams.

Any suggestions?

TIA

Did you make sure the cams were aligned while installing?

Did the cams get swapped?

Cam chain is not getting bunched somewhere?

The front guide is supposed to be located on bottom and top

make sure all the shims are seated in the buckets

I'd bet you have a cam 180 degrees out of time.
Luckily, it's impossible to swap intake/exhaust cam (different number of lobes)

Open it back up and check your timing. Remember that the crank turns two revolutions for one rev of the cam. I bet you have a valve opening into a piston.
I'm also concerned about the "feels much tighter than when I started"
Triple check that cam chain guide. You could easily have gotten it jammed against the crank on the bottom side. That would take up a bunch of slack and make it "tight" when turning it.
Unfortunately I can't give you an easy way to check the guide position.
A little borescope camera would be nice to have

OK. I'll check the shims. Ugh.

As you said, Mike... Cams are in the proper position. When I replaced them, I oriented them with the dimple up and #1 in TDC. After installing the sprockets a few times (to get them lined up such that the timing mark was still "up" when the chain was placed on them), it appeared as though the timing was straight before I installed the tensioner and turned the engine.

Now, at this point, when I turn the crank shaft clockwise, it will stop at exactly "T", but the timing marks are on the bottom (first revolution of the crank, which turns the cam shaft 180 degrees). By turning the crank counter-clockwise it will make it almost to the "T", and I can just see the timing marks.

So, my question is how can I get a cam out of time? There are timing marks on only one side. When I installed them, the marks were on the top.

Next question, how do I know if the forward cam chain guide is in the right position? It doesn't seem to have any kind of channel or guide inside the crank case. The only think I found was the notch on top, into which the guide sits flush. Is there something I should look for when sticking that thing down there? The service manual doesn't mention anything about it.

Is there some way for the chain to get fouled up down in the crank case?

Thanks, guys. I'm really feeling close, here. That poor bike has been sitting too long in the garage. Now that the sun's out, and the temps are in the 50s, we're both itching to get on the road.

With one revolution of the crank, the cam should turn 180 degrees...but it's giving me a headache thinking about whether it would make any difference...

I doubt it's the shims not seated since you wouldn't get ANY clearance if they weren't seated on the valve stem properly and it's almost impossible to balance them on the valve without getting them in the pocket.

I assume you were able to spin the cam before you put the bolts in the gears.

I ran into a road block with my first restoration that tripped me up big time. The 85 engines used a little "pointer" to indicate the T position. BUT the 86s used a knotch on the pickup coil to indicate T and the timing plate had different markings.
s288.photobucket.com/a...gplate.jpg
Since I was combining the two bikes, I somehow put the 86 timing plate on the 85 engine and now T was NOT the top center again when lined up with the timing indicator. It would be weird if that somehow happened to you, but it would screw you up. Just verify that when the crank is at T that #1 is actually TDC. Did you stop the crank at T before you started pulling the cams and were the timing marks lined up?

I figured I had a couple minutes so I'd go out and take mine apart so I could show you where the camshaft guide goes in the bottom case
s288.photobucket.com/a...010577.jpg

s288.photobucket.com/a...010575.jpg

You know what, I was just talking with Rick, and I think we worked out my problem. Since the first revolution brings #1 and #4 to TDC, and the second revolution brings #2 and #3 to TDC, I'm wondering if maybe I got them installed on the second revolution. I didn't check to make sure #1 was up when I lined up the "T" mark. I just assumed that it was. Might have been down, though.

So, first thing I'll do is pull the cams out again and rotate the engine, while supporting the chain, to make sure it isn't binding. Then, I'll stick a dowel in the #1 plug hole and make sure it is UP when I line up the "T" mark with the pointer on the case.

I'll bet you are right, Mike. I'll bet dollars to donuts that I have my cams on at 180 degrees of where they should be. That would be a bad thing because the way the lobes are set on the cam, it would mean that the valves are extending into the cyclinder when they should be retracting. That would do it, don't you think?

I did the same thing wjen I did my valves. these motors are a zero clearance motor if the timing isn't right it ain't gonna happen. Which manual do you have? I went by the factory manual and they state the small hole on the cam I was tryin to line the sprockets up with the biger holes and it doesn't work. It took me a few tries a couple beers and re- reading the steps after I relaxed a bit to understand what they meant.

Hi jvswan, correct me if I,m wrong,but it,s my understanding that the second revolution will also put 1 & 4 at TDC, the only diference being that they will change which one is on the compression or exhaust stroke. Pistons 1 /4 and 2/3 are 180 deg. opposed,not 360 deg.(impossible )
So it follows that if the crank is at TDC and the dimples on the cams are lined up all will be ok. as far as valve timing goes. It also seems to me that if your chain were bunched up ,it would never have gone back on I, d be looking at the chain guide.
good luck and cheers ,Murray

Murray is correct. Whenever the T is lined up, #1 & #4 should be TDC. 180 deg of crankshaft rotation and 2/3 would be TDC.

As long as you have both cams in sync with the timing mark you will be fine and the next rotation of the crank will put them 180 degrees off.

SO, my theory that you had one installed 180 degree from the T is hogwash since they will be in that position on the next rotation of the cam. AND I probably just confused everyone even more.

The morning brings clarity

Ok, well now I'm scratching my head again... Perhaps I need to go back to theory, because I don't understand the intake/exhaust difference. But, what I'm wondering is, if on one rotation, when the "T" is lined up, the cams are facing up (with the timing mark in top, center of the cam when looking down on them), and then on the next rotation, when the "T" comes around again, the timing marks on the cams are burried on the bottom of the cams when looking down, how can there not be a difference when installing them? By installing the cams on one rotation or the other, the valves will activate in exactly opposite sequences (because in one case the cams would be facing up, in the other, the cams would be facing down). I mean, wouldn't that have an effect on the pistons and the firing if on one turn of the engine they are facing down instead of up, and on the next turn of the engine they are facing up instead of down?

Ugh... My head hurts...

Is it just a situation where it really doesn't matter where the valves are to start with, as long as every other rotation brings them tothe correct (timing mark on top) position?

So, here I am, stumped again. It really shouldn't be this difficult to get an old motorcycle to run again.

I'll check the chain, to make sure it moves as the engine rotates. Then, I'll see if there is something I can do with the guide. Is there anything I need to know about seating the forward chain guide? It just sort of seems to stick down in the engine, except for the top, which seats in the notch on the forward top of the head. Is that right?

Ok, maybe it is sinking in. Murry and Mike, are you saying that on each rotation, one cylinder is on the exhaust stroke and another is on an intake stroke? If that is the case, then I can see why it wouldn't really matter which rotation is used when the cams are lined up. The valves are doing the same thing, just on opposite ends, for each rotation. The pistons are doing the same thing, so really, the only thing that differs is how the valves work. Right? So, no matter what, if the crank is lined up at "T", then the cams can be put on there and if they are installed correctly, then it should work no matter which rotation it is on. The only difference the rotation would make is whether #1 or #4 is set up for compression or exhaust with that first rotation.

Does that sound right? Did something finally soak into my wet noodle?

Still doesn't tell me why my stupid cams/valves/chain are mucked up... OK. What's a few more hours, after a couple hundred? LOL

I usually just coordinate the tdc mark and a screwdriver in the #1 hole and then start tearing it apart. tdc and true tdc can differ by a hair.

Dude, you're killin' me, here. No way to make this simple? LOL

I think Bob is saying to use a screwdriver down spark plug hole #1 to confirm that the T is indeed TDC for #1. Actually...any chance you dropped something into the spark plug holes while you were adjusting the valves?

And I believe, YES your assessment above is correct about compression exhaust stroke as long as T and cam timing marks line up you should be fine.

I'm tempted to mess with your head and tell you all kinds of crazy stuff but I'm getting myself confused these days!