90mm piston

[quadman21]

Any of you guys running a 90mm Piston? I'm at a crossroads where I'm either gonna re-sleeve my 440 or bore it to a 90. Any comments or suggestions on a 90mm Piston and it's reliability?

[oynot400]

That is a good question. I wondered that when I put in my 440. What other things have you done to it? Are you planning on running high compression?
Just guessing I would say if you are staying under 11:1 with a pipe, filter, the regular mods I would say you should be ok with a 90 mm piston. Although it might be a good idea to install a heavy duty con-rod.

[quadman21]

No major mods. I'm running an xr cam and supertrapp slip-on exhaust. Pretty mild. What about part availabilty? like down the road if I needed another head gasket? wouldn't a 90mm head gasket be a special order?

[oynot400]

The head gasket will be the same as the 440. You are changing the ID of the bore not the OD, like you did when you installed the 440.
I think that a heavy duty rod is a very good idea with that size of bore. I know that Sparks and some other engine builder highly recomend it. The only problem is you have to split the case to do it. Then it is a major job. :( But if you have had that kit in it for a fair amount of time it might be a good idea to have the insides check out.
Did you score a piston? or does it have that much wear? I have had my 440 in for nearly 2 years. I had the head off to check some things out after a cam failure. The cylinder looked like new yet, and it had seen some abuse. :eek:

[Mity Mo]

Just out of curiousity what is the 90mm piston in cc's. What needs to be done to acheive this. Thanks. Mo:confused:

445.3218 cubic centimeters

[quadman21]

ynot400, It's nothing bad, just wore. I've had three hones on it in a year and a half. I've had the cylinder off a few times for other things and had it honed each time just to kind of clean it up. Now it's too loose and I have piston slap. I just don't want to remove my studs to be honest. I've been down that road of leaking head gaskets and had it fixed. So I just thought of boring to a 90. I'd say I'm just going to go with the 440 again. (to be on the safe side)

[01_400exrider]

Im putting in a 440 kit as we speak, have a t4 slip on with a hotcams stage 2 cam, k&N 14 tooth sproket, what jetting do you guys use? I would like to get some opinions THANX
Phines

[quadman21]

I'm using a 152 main, needle raised one notch with a uni air filter. Thast's just me. I know of people actaully running a 146, It depends on your setup. I'm not at all "knowledgeable" about jetting. I just know enough to be dangerous.