yz 426 breaking up/ backfiring

[keithcr250r]

my bike was running perfect, i was changing in between 4th and 5th gear riding hard when the bike started to crackle under load..now it backfires/breaks up when under load but if i pull clutch in and rev its fine... if not ridden hard its not to bad..played with choke and hotstart when riding didnt make a difference..i have a fuel filter..any ideas??????

 

[prindle470]

the air filter is clean? the carb definately clean?

 

[Ol'89r]

the air filter is clean? the carb definately clean?

+1 on the carb and filter.

Drain your float bowl and make sure you don't have any water or sediment in the carb.

Check your valve adjustment.

Make sure your breather hose is not clogged with mud or dirt. (The one that comes from the top of the engine.)

 

[prindle470]

if the problem is not carbration could the timing be off a little bit.

 

[keithcr250r]

thanks for the help i will try what you guys have said and let you no..thanks again :)

 

[keithcr250r]

hey guys found problem..loose wire on coil..runs like a dream again..thanks for your help :)