Hi,
I have a 1997 blaster and it keeps backfiring, it broke one of the reeds it backfired so bad. I thought it might have been running lean so I put a 250 main jet in instead of a 220. I also pulled the fly wheel and check the key way it was fine. Can anyone help me?
Thanks,
Dennis

 

The cylinder has 120 psi, that should be plenty right? Does anyone have an ideas on what else I could check? It was running good and then it just started backfiring.
Dennis

 

what kind of pipe do u have. this was happend to me one time but it was something stupid, the oil. so idono call Yamaha lol

 

220? I have a FMF on my blaster and i run a 280.
what kind of pipe are you using?

 

I am running the stock pipe.

 

the stock jet on a blaster is 270, maybe you might wanna check that out.

 

THANKS I will try going up high this weekend, but why would it just start this? It ran fine one day then bad the next, are there any electrical parts that might cause this?

 

im not to fimilar with the eletrical side of the blaster, so im not sure. I would just check it all out. Take out the air filter and clean it all up. Do you have a stock air filter on your bike or a aftermarket one? If you have somthing like a K&N then make sure it is jetted to AT LEAST stock. Other then that the best thing to do is clean it all up. Take out the reed and cage and make sure everything looks ok. I had a friend who had a old blaster that was always backfiring but that was because too much preassue in the cylinder. I would contact a dealer and find out what the compression ratio is. If you have a different piston like a wiesco or another that is giving it too much pressur then you might want to change something there.

 

also, if it is winter where you are then you might need to re-jet for the tempature change

 

the stock main jet is a 230, and that is not going to affect your backfiring situation, 120psi is a little low being 135 is the standard point for a blaster for compression, but that's not low enough to cause a backfire, here is one thing to check:

Primary ignition coil resistance, it is located under the flywheel, but you can check the resistance in ohms at the wire connection, when they get weak, it will cause a weak spark, which is a sign of backfiring.