Well, finally....

[planedick]

I finally figured out what was wrong with Pathfinder. It wouldn't run good until 3500, kicking back, stalling from the start and crapped out at around 6000. I spent several days fooling with the carbs with no results. Yesterday while doing a run up in the garage, I decided there was too much nois in the top end so I decided to take off the valve cover and check the valve clearances. #2 intake was way over and #4 intake was way under. Seems the pucks got interchanged so I traded them and now they are all in spec, but I found the exhaust cam was 2 teeth on the chain too early and the intake cam was 3 teeth too early. Set the cam timing and put it back together. WOW what a difference. No more rough idle, smooth exceleration. Now I think I only need to dial in the mixture for a real smooth ride. Go for a ride and read the plugs.

[Ken Talbot]

You're lucky you didn't end up with a top end full of bent valves. Any idea how the cam timing got out of whack so you can make real sure it doesn't happen again?

[trbig]

Sounds to me like the cam chain got stretched too far... got loose... jumped a couple teeth. Make sure you keep that checked. That's probably a given, but you didn't mention it.

Tod

[TomB]

I found the same thing once when working on a friends bike in Germany.

We worked on it all day trying to get it to run right and gave up and had a few beers, after a few more beers we came up with the brilliant plan of starting from scratch and going right through the bike setting EVERYTHING to spec.

The next day we started at the top and straight away found both cams were one tooth out of time, the cam chain was tensioned great and we had to take one cam sprocket off to get enough slack chain to move the cams round so how it could have jumped I don't understand.

[Pat Kelly]

If both were off one tooth then It probably slipped on the crank.

[TomB]

Hmmm??

Maybe but surely the height of a sprocket tooth is the same on any sprocket

I hear what you're saying, bigger cam sprocket radius.

The chain adjuster must have been real slack some other time and when it jumped and caused bad running the first thing people do is give it a service, hence the chain tension was good when I got to it.

The mind boggles as to anyone could run an engine that long without servicing it that the chain would get so slack, it must have sounded like a bag of spanners.

[ccogswel]

Thanks for the info.

I had been messing with my brothers bike for a while now with the same issues as you listed. Didn't think about checking the timing chain. Good place to start.

This is just a thought, but do any of you think it may be possible for a chain to jump a tooth or two if you have a tranny problem with slipping gears. I mean think about it. If your chain is loose and you have a little jerk from a slipping gear if that may contribute to it as well. What do you all think.

[planedick]

What I think happened....

I understand that the cam chain might jump under some circumstances, but the chain was too tight for that even with the tensioner removed. Also I have never heard of valve spacers jumping up and changing positions with the one on the opposite end of the engine. Along with all the other things I found, like wheel nuts not tightened, brake disc bolts with the tabs not put around the heads etc, tells me that although Dave was a really nice guy and a good man, it appears he was not the best mechanic and that it was put together that way. When I got the bike it ran great, but it was noisey and I wanted to find out why. As soon as I took away the 30 degree timing advance it ran like s**t and spark plug inspection showed way too much advance and melted electrodes. I think today I will be able to get everything back to spec. Only thing left is #1 carb has a plugged low speed jet. I still have to redo the connections for the electronic flasher he put in for the LED turn signals so they will auto cancel and find out why the headlight doesn't come on with the engine start. I also got to do a lot of cleaning and polishing as all this mechanikin' has left most everything dirty.

PS, man is it ever hard getting those pucks off the valve buckets.