KX Guru Racing

Hey guys so I’m new to the forum and could really use some help. I just recently rebuilt my bottom end on my 03 kx250 new crank bearings seals etc.... also installed an new vertex piston as well. After getting the engine installed and ready to go my first start up it began to scream WOT from the getgo. So I assumed stuck throttle. Or slide checked eveything over all was well. Started again same thing. Began to do some research built a leak down tester and I am getting air from my reed gasket. So I tore it apart checking eveything cut new gastket from some gasket material. Same thing still a leak I’ve tried eveything from cork gasket material to paper gasket to rubber gasket and nothing seems to fix the leak I’ve also in a bind tried some red hightemt gasket maker. I have no idea how to stop the leak eveything else seems fine. If anyone could throw me some input that would be greatley appreciated thanks in advance

I have had good success using Crankcase sealant such as Yamabond.
But all the methods you have tired should have worked.
Something is fishy...
I'd get the factory gaskets and put a very thin layer of case sealant on both sides of the gasket.
If it still leaks then the boot, reed, or intake surface is damaged...
Let us know your progress..

I’ll be back at it later today I’ll let you know how I make out.

Turns out there’s a leak in the actual metal it’s self the seam in the intake side has some how split or spread don’t know how but iv whipped up some jb weld and slapped it on gotta wait an see now if I got it all.

Had to be something fishy

lets Hope that’s the only leak. Been itching to ride for quite some time now.