compression reduction

[tobys 2 strokes]

I am in the process of putting the engine out of my 86 500 in a 2000 kx 250 and have been considering lowering the compression. I put a late model piston in it and it seems to have really upped the compression and even installed a compression release but still more than I like . the question is I have heard of people doubling the head gaskets with good results but was wondering if anyone else has ever tried that.

[sandblaster]

Before you do that, do you know what your squish is?

[umberto]

I would be worried about leaking between the gaskets.  I know a couple of hot rod buddies that tried it with SBCs, but it never worked as well as they wanted it to.  How about a thicker base gasket?  I know Athena and KTM both include thicker base gaskets with their head kits to adjust squish.

Can we get some pics of the project too?   

[Foxx4Beaver]

base gaskets also change port timing...which could have a negative effect, depending on the type of performance you're looking for.
I would think Cometic could make a custom head gasket to the desired thickness, once the squish is determined. 

[tobys 2 strokes]

I should have the engine back together this weekend then I will check the squish I was just being lazy and looking for a quick way out I dont know if the front head studs would be long anoff with 2 gaskets and my new mount bracket any way.
There's not much to take pics of yet but will get some  It would be better if I would stay off craigslist I really didn't need another bike but for a titled 2000 250 frame ,subframe and tripples & pegs for $50.00 I couldnt resist. The Wife even let me take time out of a date weekend at the coast to get it and stuff it in the trunk of her Honda.

[umberto]

That's an awesome deal, and your wife rocks!  Having an understanding wife is the only thing that makes having too many dirt bikes possible.   If my wife wasn't as cool as she is, I would be living with my dirt bikes by now. 

[DoldGuy]

As Sandblaster stated check your squish first & then get your base gaskets from cometic, they come in .020 / .032 / .060 thickness & are the AFM which can be stacked if needed. You will not notice a difference in the port timing doing it this way on the 500, just the different compression.

DoldGuy

[tobys 2 strokes]

I am glad you guys convinced me to check the squish I had assumed it would be real tight, I have welded on the head twice once for the compression release and once when I cut off the mounting eye for my conversion and hit water.both times I have had to lap what seemed like a lot off of the head to make it flat. this thing has always been real hart to kick over even with the compression release . but with the .020 cometic base gasket I am coming up with .085 squish so even if I went without a base gasket I am to big on the squish if you can get it started it always ran good so quess I will deal with it for now and maybe fix the squish later.

[zz3gmc]

I raced a 88 500 in enduros and did the 2 base gasket mod. It worked well. On my 04 KX250/500 hybrid I tried the optional thicker head gasket and didnt like it. I run the standard head gasket now, which I like much better. Pulls taller gears in the woods much easier.

[mikectanker]

I have a 1mm thick head gasket on mine. I also have a spare. I'll check the brand whenever I get home but I'm on the road in the big truck right now