XR250 top-end misfire

[B0000M]

got an XR250 with a top end miss,

its not a blocked main jet
its not the spark plug.
runs fine until high revs then misses.

any suggestions as to what to try next?

thanks in advance

[rok-the-boat]

Faulty ignition? Loose connection that vibrates? Spark plug 'could' be on its way out.

[cheese]

It was water in teh fuel along with teh drain for teh air box blocked with what looks like 10 years of oil and shit. goes heaps better now.

Silly gissy people riding in rivers...........

[Motu]

So how did they check the mainjet without finding water?

[B0000M]

not sure, i wasnt the one who chekd the mainjet, i wasnt there.

btw river riding is awesome. just gota stop being a poofter and hit those crossing at full noise!!

skimming:rockon:

[Motu]

Makes your fist post a load of bullshit then doesn't it?

[F5 Dave]

Well this is a dead thread but reminds me of the best advise a mate told me (he's a gifted auto electrician, which doesn't mean he got given to someone.)

Listen to what people say, - But don't listen to what they say. . .

Maybe should morph that into don't believe what people say.

[Motu]

Yeah,that one of my first rules of diagnosis - if they say it's not the plugs or the **** because I've checked or replaced those.First thing I do is check their work,and 75% of the time that is where the problem is....99% of the time they have set the ****s incorrectly.Saying (or not saying in this case) that your mate checked these items is asking for him to be proved wrong.