I have a 89 LT500. I want to mill the head for more compression. Can this be done on 500`s? How much can be milled? I always run premium gas. Thank you

 

Not sure if this applies to your bike..but when you mill a head, it shortens the distance between the head and crank, making the timing chain too long. I may be wrong though. Also your valve to piston clearance may be out of spec causing valves to smack the piston.

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Boomer '99 Wolverine



[This message has been edited by boomer (edited 01-26-2000).]

 

I think it can be done. Since yours is a 2-stroke, you don't have to worry about the cam chain or valves because you have neither. Contact CT racing at www.ctracing.com. They do a lot of different engine tricks.

 

boomer a lt500 is a 2-stroke therefore dosent have valves or a timing chain
just a fyi

 

Jason, you can cut the LT500's head and surely do not have to worry about valves, timing chains or quench for that matter because none of the above pertains to you.
You do need to make sure that the squish band does not come too close to the piston because detonation will inevitably follow. This is the outer ring in the head that is close to the piston when @TDC. Also, the compression that you are shooting for needs to match the riding style you are aiming to. If you are wanting a high rev top end monster, then not only should you NOT bump the compression too much, but the squish band should be narrowed. On the other hand, if you are looking to gain acceleration in the mid, then you can bump the compression a little more and leave the squish band alone. However, if you DO raise the compression, especially on something as large as a 500, there will be a good chance that you will need to run high octane fuel so that your piston does not form the "ashes of death" that detonation causes.
I gave you this info just "for your info" and I don't think you should perform the mod yourself. Pay the $80 or so and send the head off to a reputable shop. Tell them what your wanting. CT Racing was mentioned and they would do a great job in my opinion.
Trax310

 

I know my machine is a 2 stroke. I`ve got it in about 1000 pieces right now rebuilding everything. I was wondering if the guy that owned before me knew that grease was avaliable to the general public thou. Besides that I only want to slightly raise the compression so do I mill it .010-.015-.020? what do you recomend. The 87 zilla had higher compression so I know I could get a little more from mine.

 

I race a CR250 in motocross events and to get the extra compression I use Cometic gaskets. They're a few thousandths of an thinner than the stock gaskets. The difference in low to mid power was noticable. I don't know if Cometic makes gasket kits for ATV's but it's worth a try and will be much cheaper.

Dave