81 750 LTD Camshaft Installation/Timing Help

After checking valve clearances, I pulled the camshafts out to replace shims. I also removed the wedge cam tensioner. I followed the FSM installation procedures for installing the cams. I set pistions 1 -4 at TDC using the timing mark. I dropped in the exhaust cam and lined up the mark even with the top of the head. I did the same for the intake cam and then counted the links as described. When I installed the caps, both marks moved up a little. I then installed the wedge tensioner.





I still have slack in the the chain. Do I need to do anything else? Is it normal for the cams to move a little when snugged down? I'm a little nervous as I haven't done this before. The last thing I want is bent valves, etc.

Thanks
Nick

I think I figured it out. I got up this morning and slowy turned the crankshaft. The cam chain tensioner kicked in and the slack was taken out. I could then see that I was off a pin or so on the exhaust cam. I popped out the cam tensioner wedge and removed the cam caps. I re-seated the exhaust cam and then the reseated intake with the mark between pin 45 and 46 again. Then i put the left inner caps on to sinch the cams down. It looks much better now. I think the problem was that there was too much slack in the chain the first time since the tensioner wasn't installed. Later on I'll put the rest of the caps on and double-check the timing marks.
Thanks

Nick

Take the wedge for the tensioner back out, before installing the Valve Cover. Don't over torque the camshaft journal bearing holders. Some of the service manuals list this as 12 foot pounds, which is to much. It should be in Inch pounds, like 90-110.

It took me awhile but I think I have the mechanical timing right. At TDC for 1-4, the timing marks lineup on the deck of the head and the camshaft notches are opposing. I also counted off the correct number of pins from the start of the mark on the exhaust side.

The only problem is that after swapping some shims, some of the clearances are alot smaller than the initial measurements. Unfortunately I didn't observe the timing marks when I took the valve cover off. So either the timing was off before I started or something is not right with the cams right now. Any feedback would be helpful as its driving me crazy. It doesn't seem that difficult, but...
Thanks
Nick

Are you checking the valve clearance with the lobe pointed Away from the Valve/ Shim/ Lifter? Or are you following a service manual procedure, so you are checking both IN & EX for #1 at the same time? The manual would tell you to Do certain valves with the 1-4 at TDC then rotate, and do the others. Most would just point the Cam Lobe Away/ up, then check clearance.

The initial readings were done with lobes pointing up. I started to do it that way again then looked at the service manual which had it stated as you put it.

I borrowed a friend's leakdown tester. I tested all 4 cylinders. I set TDC for 1-4 and tested cylinder 1 and 4. Cylinder 1 held air at the valves. I tried cylinder 4 and it leaked out the intake. However, once I turne the crank another full turn and tested again, it held. I did the same test on 2-3 using the other timing mark and the results were the same.

So, a few questions - do the cylinders alternate intake the way I desribed above?
Since all 4 cylinders didn't leak at the valves, does that confirm the mechanical timing is correct?
Are the valve clearances there to account for heat expansion once the engine is hot?

Thanks
Nick

You need to turn the motor, each time you go to check a cylinder for a leak down test. Start with #1 and follow the firing order, turning the crankshaft by the 17mm wrench size nut at the right end. not the 13mm wrench head bolt. Follow the firing order and align the 1-4 mark for first #1 then the 2-3 which might be only a "T" mark, 180 degrees at the crank, for the next. Then back to the 1-4, another 180, to do #4 then again another 180 to get the 2-3 "T". Each time the valves for that cylinder tested should be loose, so clearance can be checked at that same time. Each on at the top of the compression stroke so both valves are closed, and have the proper clearance. Then check for cylinder leakage.

Thanks alot Motor. It makes sense now. I was able to check the valves. The FSM has the range from .08 - .18. I have a couple of valves on the low end and a couple on the high end, but all ok to run with now that I have the carbs cleaned and ready to go.

When I address the valves again, what is the target clearance I should try to get to with different shims? Middle of the range?

Nick

I buttoned up the bike and got it running. With the cleaned carb rack it idles perfectly. #2 pipe is still not hot. I did a clear tube test on carbs and they were in spec. I have spark on that plug. Valve clearances are .076 for exhaust and .064 for intake. I have the same measurements on #4 and it seems to be OK. Compression test on #2 = 120 psi. Short of ordering shims, any ideas for troubleshooting/next steps?
Thanks
Nick

nicksorg wrote: ...got it running...#2 pipe is still not hot...clear tube test on carbs and they were in spec. I have spark on that plug. Valve clearances are .076 for exhaust and .064 for intake. I have the same measurements on #4 and it seems to be OK. Compression test on #2 = 120 psi. Short of ordering shims, any ideas for troubleshooting/next steps?....

#2 will probably combust with starting fluid sprayed into the carb intake.

Non-combustion may result from lack of fuel mixture due to an imperfect carb pilot circuit.



Good Fortune!

Thanks Patton. I remember checking the passage to the pilot with a small penlight, but maybe there is another blocked passage. I'll pull the rack tonight and go through #2 one more time.
Nick

Clogged pilot jet. I cleaned it and put the rack back on. It runs nicely. Thanks for the help. Carb sync up next.
Nick