hey guy's i'm new 2 this....i got a 1991 lt250r p/p-fatty pipe-bore60-2+2 rear- etc... i was ryding it the other day in the snow and it just bogggged out>??? and now when i try 2 kick it ...it jus backfires.>??????even with a new plug..! any1 got any idea on what i should do? thanx

 

how long were you riding it? If your temps are anything like they are here its probaly about 10 degrees out. I'd be willing to bet your jetting was off due to the cold. Check your compression first just to make sure you didn't ruin a piston.

 

i was ryding it 4 a hour.. and i jus put a 190 jet in it...what should my compression be>? thanx

 

check your reeds.you may have a broken one and your crankcase isnt sealing up.

 

thanx 4 ur help...when i bought the quad i did the top half and when i took it apart the piston was burnt at the top forming a hole...>? any idea why>?

 

Sounds to me like you are running lean or are experiencing an air leak. I would do a plug chop to see if your jetting is off, along with what semms already mentioned.

 

190 mainjet, thats stock size! with a pipe and a big-bore you need more fuel. your running WAY to lean, bump it up to a 240 and move your needle clip up a notch.

 

even in cold weather>? and what should my oil mix be>? cause i been mixing it 32:1..and i'm getting oil leaking from my header>?

 

i will post compression numbers directly from the manual when i get home from work (about 2-3 hours). The hole that burned through the piston was most likely caused by a lean condition like pendejo mentioned.

If your compression turns out to be fine and your plug isn't light light grey (almost white) then it may be a timing problem.

Check the magneto and make sure it didn't shear the wood druff key by trying to turn it by hand.. if it turns and the engine does not turn over with it then this is your problem.

Also check the pulser pick-up coil leads. its located next to the magneto. I once had a lead fray and eventually this led to it not starting and only backfiring.

 

If its a mikuni carb it would be well above a 190 main... they run higher numbers than kihein. (260 is close to stock, i think 240 for 85-86... its also in the manual.. i'll post ot later)

If its a kihein carb then a 190 is kinda big. I run a 165 in mine and its using a 38mm kihein pj carb.