Jianshe Puma 250 - Troubleshooting help/ideas???

[dave2]

I have a chinese (Jainshe puma 250) quad that is a yamaha beartracker knockoff. I think the problem I am having is a generic (to other brands/cycles) one. Here goes:

It won't start with the electric start, cranks good but won't fire. A quick pull on the rope and it kicks right off.... Idles fine and revs decent. After it is warm it will sometimes start with the starter but usually not. Always starts right up with the rope.

This just started after I ran it without oil and almost siezed the motor..... Things got pretty warm down there...... (has new cyl, head and gasket, piston, and rings now with 12 bar (175 psi) compression)

The way it's acting is there just isn't enough power to fire the plug when the starter is turning. Also, when you ride it, it goes along just fine to about half throttle then looses power after..... Carb is fine, has been cleaned and adjusted..... Even put a carb off the same one that was/is running fine with the same results.......

Any idea where I should look? As far as I can see, there only 4 parts to the ignition. The CDI box, the stator, the coil, and the sparkplug. The part exposed to the heat was the stator, but could it be causing the problem I'm having?

Or can someone point me to an active/helpful forum for quads in the UK. American ones don't get a lot of action that I see and the german ones don't have a lot of "fixers" and the language barrier don't help much.

Thanks for any tips.

Dave

[oxidized_black]

i think you are right and it is more electrical. if you can get the specs for the electrical, you might find the problem fairly easy. there is a minimum for the stator output and coil. there is a voltage regulator there i would think also. you can test meter all these and it will show you what is weak or lacking. i'm not sure if you can test the cdi box, but if your stator is showing well, and your coil, it might be the cdi, but you want to make sure first. a buddy of mine bought the rhino knock off from astro, and i think these chinese brands really skimp out on the electrical components from what i have seen. all his problems have been cheap electrical mishaps...

[dave2]

Thanks! I'll see what I can find.

Never was "perfect" but I got along with it before (started OK cold and warm but had to use the rope to start after I gave it a good workout. The stator and maybe the coil fits because if the wax (??) insulation on the coils was already going weak, the heat buildup could have just made it worse. Was working it hard the day it quit also (4x6ft chain harrow) warms it up to begin with then the lack of oil (long story) just heated it up more.

[oxidized_black]

i thought i might have a beartracker service manual, but i didn't. it would have told me the specs for the electrical. i'm looking online now for it... but if you have a connection in the U.K., they might be able to send you the specs in an email too.

just funny if it was a bad stator, it wouldn't run, or would have weak spark to the coil, but a coil can work cold until it gets warm and then fail...

[swampcat07]

I had the same problem on my ATV. The only difference is I am running 11:1 compression. It turned out the be the brushes on my starter was warn but here is what I did before buying a new starter.

Here is the typical checklist:

Make sure battery is good and fully charged.

Check all of the grounds for corrosion or loose connections.

Replace the plug, some plugs will spark when outside of the engine but when under pressure they fail.

Replace starter wire with heavier gauge hot and grounds. I think I used 6 or 4 gauge. (The smaller the # the bigger the gauge)

Try pulling the pull start or removing the plug to bump the engine so the engine is not on the compression stroke when starting.

(Even though the starter was going this helped me to get it started and get it around)

Check all the electrical components to see if they are within spec.

Replace the starter.

[oxidized_black]

found a service manual '98-'01 beartracker ...

Yamaha YFM 250XL(C) Beartracker '98-'01 Service Manual.pdf