alrite this is my problem. i'll put a new br9es plug in my bike go out riding for about 20 mins not even, and then the spark plug will die. i'm running klotz r50 with 93 octanewith band new reeds . But i thing is i think its my carb not tune'd rite but i got a main jet #142 . I cant really hit power band till like 3rg gear it just doesnt sound rite then it just hits in 4th, 5th and 6th.

 

Hmmm. Sounds like you're a bit frustrated.

I would check the obvious first - do a plug chop on a clean plug and check it out for lean/rich conditions, compression check, check for leaks, etc.

To do a plug chop - just ride your bike - and kill it with the throttle still open. (Hit the kill switch).

Usually the repair manuals explain the different plug colors fairly well.

A simple way to test for bad leaks is just to spray soapy water around where the engine surfaces meet while its running. You would see bubbles right away.

You would need a compression tester (usually you can get a loaner from the auto parts store) to test compression.

Important!!!! -> Don't 'hit the power band' if the bike isn't running correctly. You could ruin a perfectly good engine.

 

Try a NGK B8ES or BR8ES, that is the plug it is supposed to take. Gap it to 24 thousandths and see what it will do. The main jet doesn't sound too big, but can be very mix sensative. I prefer 91 octane with Castor 927 mixed at 40:1 (5 gal to 16 oz bottle) for a relativley stock motor like yours. Then try cleaning out the entire carb. Check the needle position and the size/condition of the pilot jet. Check for good spark; without it, the mixture may not be being burned totally and could clog up the plug... Lots of posibilities, I would try the correct plug and something other than Klotz, but that's my preference...

 

Yeah, go with the BR8es for starters and lean the fuel. I'm running just under 40:1 myself. What kind of air filter are you using? A K&N filter kept CLEAN will help as well.

 

i'm pretty sure about how to fix the problem now its my pilotjet i went to big on it and its way to rich