1975 250 motoplat problem maybe?

[herman]

I have just finished a complete rebuild on my 1975 250 penton but iam having a problem with it running good it wants to miss from mid rpms up. And sometimes when i stop to let it idile it stops like i have hit the kill button.I have retourqhed all the head bolts to 22lbs.i have scraped all the paint off were the coil mounts.How do you know if the motoplat is going out? Does it just quit or does it act up a different way? Thanks Herm

[OUCWBOY]

Herman,
What you describe sounds like the classic case of poor ignition ground. Not only the coil connection to the frame, but the engine must have a good ground to the frame as well. I know this sounds routine, but it doesn't hut to double check.


Donny Smith

[firstturn]

Herman,
  I agree with Donny on this and will include my former comments.  In addition please double check for any problems in the carburetor.  Also do a leak down test if you have the equipment.
  What is the plug reading?
  Next you can have Penton Imports check the ignition system and the flywhell to besure  that it is properly magnatized.  As I have stated before I have had limited trouble shooting on the KTM engines probably I so little problems with them when I raced them.

Herman,
Just a note, the first thing I would check is all that you have all good grounds. If you rode it for a while before it started this problem something could have loosened up. Also I have seen this occur on powder coated frame where you start out with a marginal ground and it goes down from there. Check all engine bolts and coil connections.
Next check for any trash in the carburetor. This is just initial things based on the limited information given. I have only have limited time right now, but will see what the experts come up with. Good luck.

Ron Carbaugh

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Edited by - firstturn on 04/15/2004 08:41:54 AM



Ron Carbaugh

[Larry Perkins]

Herm

It could be the grounding but I have seen Motoplats do lots of weird things on their way to death.  Irratic running and quitting is one of those.  I would send it to Dane to eliminate or confirm that possibility.  He will call it good, bad, or suspect.  I suspect he will say suspect.  Sometimes suspect ones will work better with the Sachs motor(useing a different flywheel of course) but won't do well with the bigger KTM motor.  

I believe there are two kinds of Motoplats, however.  Bad ones and ones that WILL go bad.  Consider PVL it is pretty much a forever ignition.  Some people don't want them because they want to build an enduro model.  I say put the lights on and it looks the part.  When was the last time someone said, "Hey do those lights work?"  For motocross the PVL is great because you can run the much lighter stock PVL flywheel and it revs freer and can wail like a Japanese bike.  You get Penton power and durability with Elsinore type rev.

[herman]

Thanks to all of your help again it was a bad connection frame to motor.I sure hope that i can help all of you someday or some way.Herm

Herm

[firstturn]

Herm,
  Thanks for the nice e-mail.  One thing is help someone, but another is the great Thank You.

Ron Carbaugh

[OUCWBOY]

Herm,
I have to agree with Ron, that was a very nice E mail you sent. Makes us all feel great to help someone and even better with a thank you.


Donny Smith