Engine Wont Catch After Maintenance

[MNGATOR]

Assuming that you are getting spark and you did put some fuel in the cylinders and still nothing. I would pull the tappet cover and the plugs and check that the valves are closed when piston is at top dead centre, just to confirm that nothing went wrong when you replaced the cams. Recheck the clearances just in case.

Would I verify that valves are fully open and closed by looking to see that cam lobes are perfectly perpendicular to the shim surfaces? When engine is at TDC of course.

This is all getting me steamed up about the Clymer's manual! Why wouldn't a manual give information on how to verify one's work?

[1100Gee]

I would definitely do a compression check on it as robertbarr recommended in a earlier post. If your cams are off, I would think your compression would also be very low. As a side note, does anyone know if there is interference problem with the valves/pistons if the cam timing is too far off?

I just noticed that you're from Waconia, practically neighbors. I just live up in Richfield.

[BassCliff]

Hee Haw Howdy!

Hi Mr. MNGATOR,

I'm sorry I'm late to the party. I just want to invite you to my little BikeCliff website where you can download a manual for your bike and pick up your mega-welcome. It's good to have another 850 shafty in the room.


Thank you for your indulgence,

BassCliff

[MNGATOR]

Two quick questions: 1) Would performing a compression test tell me what I need to know just as well as taking off the valve cover and inspecting the cams? 2) Is blowback through the carburetors definitely a bad thing or is some of it normal?

[80GS750]

some backpressure through the carbs is ok....

it just feels that way until you get them synched right, then they will pull mass amounts of vacuum every revolution...

a compression check would be very helpful.. you will have an idea by those numbers if your cams are off or not. if the valves are opening or closing wrong, your numbers will be way off! you would have to be way out of wack for the valves to make piston contact... i would think

[Matchless]

I wonder if he got this sorted out?

[Burk Ferden]

Check The Timing!

I recently had the same problem, it seems there were 2 timing marks on mine. they both looked like TDC. After rebuilding the engine it wouldn't even start. I took it back down and timed it again this time to the other mark and it now starts better than my new VStrom. Seems the engine was 180 Degrees of of timing. no wonder it was spitting fuel out the carb intake.

~Burk

[MNGATOR]

I wonder if he got this sorted out?

Thought I'd finally show some graciousness and let you all know what is up. I did give up and took it a local 'repairs-motorcycles-on-the-side' mechanic. He is a non-drinking man but this bike nearly had him downing one!

Much of his problems with it I can, in hindsight, say was bad transfer of information when I took it to him. 1) When I told him that I'd had it all apart down to the piston block he didn't think that I had taken the valve assemblies out, too. 2) When he exhausted all other leads (had the bike all back together, it started right up and ran great.... initially. After five minutes of idle it ran a little rough and after another five minutes it ran poorly. Compression was great when the engine was cold but cylinders #2 & #3 were terrible at operating temperature) and had thoughts about possible valve problems, and we communicated, I forgot to mention that I had removed a lot of carbon deposit from two of the valves. This led to him retrying the simpler fixes one more time and they, again, didn't work. 3) Finally he knew that there could be no diagnosis besides bad valves and sent the head to a machinist. They verified that #2 & #3 exhaust valves had lost their metallurgic integrity, were stretching at operating temperature and the valves were not seating tightly.

That machinist gave the head a complete work-over and the bike now runs superbly! It's a great bike and I'm looking forward to being it's gentle, doting owner for many years and many thousands of enjoyable miles to come.