Blew up during a race

[Maverick302]

Finally got the computer workin so now im back. Anyway, I was racin at flying dutchmen in pine grove in an open b class. I was racin against 23 other quads goin from predators and cannondales to banshees and 450s, even a stock warrior showed up. All the four bangers hooked up quicker and got the holeshot but i managed to pass them halfway through the first lap up to 3rd or 4th place (pretty good for me). I was in a battle between a predator, two 450s, a wicked 250r, and two banshees (one, the same setup as me, 2002, the other an older yellow and blue one pretty tricked). Anyway, im kind of a puss on the big jumps, but i had more skill on the open trail part. Got to a straight we all floored it, I (from 5th place) was inchin up to the two in front of me when i blew the left cylinder. It felt like the the left side turned into a blaster and was gettin pushed around by the right side. It barely runs, gets good spark, has clean carbs/filter, and wont rev over ~6000r's. I don't know what happened but im ready for a rebuild.

[bansheefreak]

sounds like you might check hed gasket

and or plug....i would think if you burnt a hole in the piston it would not run at all

[Banshee~]

Man it sounds like you were kicking some ass...what type of race was it?

[Maverick302]

It was a hare scramble. They have an MX track surrounded by wooded trails. Takes a lot out of the rider, it's pretty tough. But hell all we have in PA is mud and rocks so i'm used to it. Bet I could't take a full day in the sand though.

[.]

Is it backfiring and such? Have a compression gauge? I'd check things out before you go ripping it apart. A leakdown test might be a good idea as well.

 

You'd love riding sand, its like riding on a pillow compared to the rough ass trails around here. Ever ridden in a big coal field that is pretty ground up? 8bees or whatever its called used to have a good area like that until the pulled all the hills down so it would be "safer". It was kind of like riding in that, but even softer.

 

It's kind of rough with all the ruts if you have stock shocks, but you dont so you'd be set to hit up some sand. I wish there was still some good open places to ride in NJ like the Port.....but everything pretty much is running from the moment you pull it off a trailer.

[Maverick302]

Compression is 137 and 135. It's acting real erratic...It's running fairly smooth now and revs up fine, but either cylinder may cut out. It hits a flat spot around 2000r's and at 5000r's, and at one point it hit the flat spot and wouldn't rev out of it, so i hit the killswitch and it still ran, i pulled both plug wires, still goin...It wasn't puttin any exhaust, just blowin a little cool air. I covered the tips with my hands and it fell and died. It's confusing the hell outta me. I cleaned the carbs, the reeds are fine, it's gettin spark, and fuel flow is fine. I put in 90 octane gas, the normal ratio, no octane booster, on 20cc domes. I usually run that with octane booster or that and 104 mix, is it a possibility that it's detonating from the gas? I've used the mixture before and it ran fine, it just started actin up during the race. Thanks for any help.