It's dead!!!

Ok, I was out riding last weekend and about 17 miles into my ride on a 90+ degree day in a lot of tight trails my bike died. I hear it boiling and I figure I overheated it and that's why it died. So I wait for it to cool down and try to start it again. It won't start, I try the electric start and kicking it and nothing. We figure it's the spark plug, so I get home and put a new spark plug in, nothing! I check for a spark, it has spark. It's turning over, it's getting spark but it just won't start.

The lever that came along with the kick starter, has always worked so that when you pull it in, it stays in that postion. Then you slowly kick it until it pops (TDC), then kick it and it starts right up. The lever keeps poping out, it won't stay in no matter the position. I'm guessing it has something to do with that lever. I pulled the cover and all I see is a a pin that goes through the case with a flat side. I don't have the instructions or manual that came with it (the kick starter) because the dealer installed it and never gave it to me. I don't know if something broke off of it, there is nothing obivously missing form it.

1) Does anyone have any ideas?

2) Does anyone have any pictures or diagrams of what it should look like?

Any help would be appreciated, thanks. :bonk:

PS. My brother thought the compression felt low, I'm going to try and get a compression kit to test it but I thought this would make it hard to start not impossible. :excuseme:

You are close. The CR shaft has a flat on it. Turn the CR shaft and the "not-flat" part of the shaft contacts the cam follower and pushes the follower down opening 1 ex valve a little. Valve spring pressure on the CR shaft holds it in place. As soon as the cam lobe contacts the follower and depress the valve further, pressure on the CR shaft is released and the CR returns to the off position. If for some reason the ex valve does not close all the way, there is no pressure on the CR shaft to hold it in place. Bent valve, carbon under the valve face are 2 possibilities. Bent valves are from over rev, failed cam chain tensioner, lose primary nut or some other failure in the valve train. Carbon under the valve will self correct if you can get it started but you want to verify all the valve train is good first.

Also check the CR cable adjustment. It just has to pull far enough to position the flat correctly.

Low compression will prevent starting especially on a big single. Tow (which I like to avoid) or coast down a long steep hill might help to get it started with low compression.

You are close. The CR shaft has a flat on it. Turn the CR shaft and the "not-flat" part of the shaft contacts the cam follower and pushes the follower down opening 1 ex valve a little. Valve spring pressure on the CR shaft holds it in place. As soon as the cam lobe contacts the follower and depress the valve further, pressure on the CR shaft is released and the CR returns to the off position. If for some reason the ex valve does not close all the way, there is no pressure on the CR shaft to hold it in place. Bent valve, carbon under the valve face are 2 possibilities. Bent valves are from over rev, failed cam chain tensioner, lose primary nut or some other failure in the valve train. Carbon under the valve will self correct if you can get it started but you want to verify all the valve train is good first.

Also check the CR cable adjustment. It just has to pull far enough to position the flat correctly.

Low compression will prevent starting especially on a big single. Tow (which I like to avoid) or coast down a long steep hill might help to get it started with low compression.

Thanks Noble, sounds beyond my capabilities. I may have to surrender it to the shop even though I hate to.

Sorry I failed to mention that we did try pushing it downhill but it wouldn't start. I don't think I over revved it and the cam chain looked ok, not loose at all but as for a loose primary nut or some other failure in the valve train, I'll have to have my brother look at it or get it to the shop. Thanks for your input.

Sounds beyond my capabilities.---maybe not if you have some good help.

Sorry I failed to mention that we did try pushing it downhill but it wouldn't start.----I was thinking of a BIG hill. Paved for good traction and about 30 mph in 3rd gear for 1/4 mile. That should build some compression. Alternately towing (which is dangerous). Or jump off a car battery. The car battery will crank it faster and for longer but you do not want to crank it for more than about 15 sec continuous. It will overheat the starter. You have to let it cool for several minutes after a long crank. A starter has about a 10% duty cycle which means you can use it for about 1 min in 10 but not a full minute all at once.

I don't think I over revved it---No, probably not.

And the cam chain looked ok, not loose at all----OK

But as for a loose primary nut or some other failure in the valve train, I'll have to have my brother look at it or get it to the shop.----The problem with the primary nut is if it comes loose, the crank stops driving the cams. What you are looking for is if the cams are still in time with the crank. Just line up the mark on the flywheel in the inspection window and look at the cam time marks. Cams move with the crank? Cams still in time?

With the top cover off you can see enough of the cam stuff to see if anything is seriously wrong and you can operate the manual compression release to see how that functions. You can also see the auto compression release to see if that is functioning properly. Fly weight, a very light return spring and a few operating pins.

My guess is if you can get it started it will run fine. I just like to check out as much as I can first.

Thanks again Noble

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