87 XR cuts out intermittently

[Dan Turner]

I recently acquired an 87 XR600, that cuts out every now and then. Doesn't matter if it's hot or cold, it will run great for a half hour, run crappy for 10 minutes, and run good again....then repeat. This bike does have the dual carbs, which I've thoroughly cleaned, inside and out. Jets are both 128s with a 45 pilot. It has an older Supertrapp, and a K&N Filter that's clean. The bike always, always idles perfect and is not too hard to start. I just need a little guidance as to what is wrong with this thing.

Thanks, Dan

[Mantrasonica]

Sounds like a fuel problem to me. Stuck float?

When you cleaned the carbs did you carefully inspect the float needles? Seems to be a weak point in these carbs. Next time it craps, try tapping on the body of each carb with a screwdriver handle or a box-end wrench. If that solves the crap, you probably need new float needles.

Tim

[Dan Turner]

When I had it apart, I looked at the needle, but didn't see any kind of groove or anything obvious.

Dan

[Dan Turner]

Last night when I was messing with stuff, I accidentally unplugged the headlight, and it started to run better. Does the lighting circuit have any thing to do with the ignition curcuit, or os this just a coincidence and part of my intermittent problem? I bet the neighbors are tired of me racing up and down the street, though.

Dan

BTW, I tried tapping in the float bowls when it was cutting out and it had no effect.

[frankstr]

Sounds like a electrical problem, possibly your stator is going out or a intermentit short.....or...

[Dan Turner]

When I bought the bike, the voltage regulator under the seat, bracket was broken. Looked like it vibrated and cracked. I took it off and welded it back together. It still did the cut out thing before and after, so I don't know if that may be a problem or not. Just a little background info.

Dan

[atkxr600]

I had my 86XR600R do that same type of thing, it would run ok, them run like crap. I checked it all over, could not find anything. Finally took it to the dealer where I knew the mechanic. He looked it over and after two days called and said he didn't see anything obvious. He remarked that the stator checked on the "low" side but still within spec. We decided to try a new one anyway, fixed the problem.

Hope this helps.

[Dan Turner]

That's kind of where I was headed myself. What is involved with changing the stator? is it in front of or behind the flywheel? I'm fairly new to all of this but I'm not afraid to get my hands dirty.

[TimBrp]

I'm in the same boat with an 87 xr250. I haven't replaced the stator as I don't know if that's the problem and didn't want to waste another $125 on nothing, yah know. Mine runs fine when cold then when it heats up supposedly the stator breaks up and misses in the midrange. Only when hot and only in the midrange. Let us know how you make out..

[thouk]

Try the kill switch. I had a '86 that did that during a race. I ripped it off never to be used again. I hope that helps. Tony

[Dan Turner]

I'll try the kill switch....I still need to know how to change the stator, though.

Dan

[targetdrone]

The light has nothing to do with the ignition. On an XR600 there are 3 coils on the stator: The source coil (the small one for the ignition) and two lighting coils. It is an oil bath type, meaning you will have to either drain the oil or just lean the bike over on its right side and remove the cover on the lower left side of the motor. The stator is bolted to the inside of the cover. The flywheel has the magnets on it and is somewhat dish shaped.

If you are going to replace it with a used one, make sure you get one for an XR and not an XL. The stator for the XL has 4 coils (1 source, 1 lighting, and 2 go to the charging system).

It is easy to swap out, but expensive. This is especially true if it is not the problem.

As for the cutting out problem, CHECK THE WIRES GOING TO THE COIL. Clean all the connections there and apply dielectric grease to the plugs.

[Dan Turner]

Thanks for the info. I went ahead and ordered a Ricky Stator, so while I have the bike torn apart having the suspension done, I'll put the new stator in and check all the connections for corrosion/looseness. I give you an update probably next week.

Dan

[TimBrp]

Dan make sure where the rubber grommet plugs the case for the stator wires that you use some silicone to seal it up. The new stator grommets may be too small and I've heard of people losing oil through there. Just an FYI.

[Dan Turner]

Thanks, that's the kind of useful information that saves a lot of headaches.

Dan

[TimBrp]

No prob!