KDXRIDER.NET

Now that I'm putting my 91 KDX250 back together, I'm thinking about doing the thinner ('88) KX250 head gasket mod. It's about half as thick.
I was wondering if anyone knows if this makes the bike run leaner or richer, or if the difference is sublte enough to not really matter.
I'm also wondering how much more octane sensitive this will make the bike, if anyone happens to know.

This is a good question for RB, but I'd guess that a 15deg temp swing would alter the jetting more than a large compression change....Much less the minimal change the head gasket will provide.

Well that is a loaded question......,

For the most part, my head mods will tend to make the engine run maybe just a little richer. But then again I'm not just raising the compression, I make other changes that make the burn more efficient (burning more of the fuel mixture).

On the other hand if you just raise the compression without taking a lot of other things into consideration, you could make the engine run to hot and lean

Ron

Thanks. Doesn't sound like it should affect jetting much, if at all.

Best bet is to do a simple plug chop when you've made the change. All it costs is a couple bucks and about an hour's time to go through everything, even swap a jet if needed. Let us know what you discover.

Indeed. It's a manditory skill to know, IMO.