PREIGNITION

[Josh Z]

My bike is pre-igniting in the mid-range. If I lug it down or shift too soon I loose all my power and it almost stops. I have slowed the timing to almost 0, and am still running VP 110, and b10egv plugs. Any suggestions? I'll post what my compression is ASAP. This is what else is done to it '97 'shee bored 20 over, CPI Inframes, Fox Floats up front. Boss Noss 20 shot (x2), Trinity stage 4 intake w/ a Keihin 35 PWK 230 main, Hot Rod crank, Pro Design Cool Head, don't know what dome size or compression (yet). Running VP 110 with Red Line Two-Stroke racing oil 40:1. Considering alcohol. Please Advise!

Edited August 16, 2010 by Josh Z

[AKheathen]

well, you need to know what domes you are running first off. elevation, and porting. if it is detonating in the mid, i guarantee it is detonating in the top-end. now, if you have been running it hard like that, there's possibly damage to the piston already. on the other hand, if it's not detonating, and you are just assuming, it could be something simpler, like plug gap, jetting, weak spark, too much octane, etc. measure squish, find out what domes/cr, and you may need to pull the head and take a look-see at what you have going.

[06specialedition]

What part of Utah you located at Josh?

[Tedder]

230 mains - You sure your not way rich at WOT

[Josh Z]

I am located just out of cedar. And yes a 230 main. it is a single carb setup so that one has to feed both cylinders. The plugs were getting too hot before (it had b8egv) but now I am at b10egv and they are much cooler. the jugs don't get hot at all tho! I haven't yet ran the nitrous. I just bought it but haven't installed the whole kit yet. I will do a leak down and a compression test friday morning and post it on here asap. Thanks for all the input tho! keep throwing out ideas! whats the difference between pre-ignition or detonation? i thought they were the same thing?

[Josh Z]

ya i was one of them, then i did some research. wasn't trying to be a dick, just thought it would be better for you to read it than me explain it. i suck at explain shit.

No you weren't a dick. it's way easier to link it than to type all that! and I think it is detonation. Thanks.

[sleeper06]

I just put a 2-1 on a heavily ported motor,it plug chopped at 200 main jet a hair rich,You might be masking an air leak problem with more fuel and shees a dud now

[mopar1rules]

If its deto, it will show itself on the domes and piston crown. The domes will have all these little specs/pick marks on the squish band face. It will also appear to be sandblasted.

[AKheathen]

wow, i just noticed, you are all the way up at a 10. you need to go back to an 8 and tune it to run good with those first thing.

[Josh Z]

My bike is pre-igniting in the mid-range. If I lug it down or shift too soon I loose all my power and it almost stops. I have slowed the timing to almost 0, and am still running VP 110, and b10egv plugs. Any suggestions? I'll post what my compression is ASAP. This is what else is done to it '97 'shee bored 20 over, CPI Inframes, Fox Floats up front. Boss Noss 20 shot (x2), Trinity stage 4 intake w/ a Keihin 35 PWK 230 main, Hot Rod crank, Pro Design Cool Head, don't know what dome size or compression (yet). Running VP 110 with Red Line Two-Stroke racing oil 40:1. Considering alcohol. Please Advise!

WELL. my compression was down to about 145, and I did a leak down and found a leak in the base gasket. So I tore down the top end to see the damage. My piston and cylinders are still good! but I do need new rings! So I am gonna replace the rings and base gaskets and try it out! Thanks for the input all! I'll keep you posted!