Hello KLX250 forums.

I am happy to announce that today I got my 292cc big bore kit installed! Its the OEM KLX300 cylinder and piston. It was a slightly used kit having done ~8000 kilometer, but it looked very good. I got it from grahamgover who is also a member of the forum. Graham wanted to upgrade to a 331 kit, so I bought his old kit with a spare EJK controller he had for cheap. Very handy for a poor student like me. Thanks to graham for being very flexible in his delivery (he actually bought it with him as he was travelling to Europe so I didnt have to pay customs fees).

Installation was smooth, no issues at all. I used the EJK fuel controller to give it more fuel. It fired up on first attempt and was immedietly rideable. I´ve done 25 kilometer trip and the only issue I found was a bit of a hiccup around 4500rpm when you go from cruising speed to accelleration. Not sure what it is, but maybe it can be fixed by playing with the EJK fuel controller setttings.

Very happy with the increased torque. Its a nice increase in pull especially from around 5000rpm to 7000rpm. Slightly deeper soundtrack and only slight increase in vibration at very high rpm (7000rpm+).

I still havent got an aftermarket exhaust, so now I am wondering how much of a difference that would make. Not to mention the 331 kit

 

Looks great! I hope you've at least destricted the stock exhaust,that will make a big change in performance. If you've still got the peashooter get a 1" holesaw and open it up.
have fun
marc

 

Good job! its great fun to work on a bike and not have anything blow up

 

I too went with the OEM 300 jug and piston too instead of a bigger kit. I got a good price on a new one through the shop I used to work at, and I kind of liked sticking with the stock 11:1 compression ratio for fuel quality issues...thought I don't think anyone has octane/detonation issues even with bigger bore, higher compression kits. With your fuel injection, it should be a nice addition. On the aftermarket pipe, I'm in the camp of opening up the exhaust and intake with a bigger bore of any kind to take full advantage of any power gain.

 

Welcome to the EFi Big bore club!! Enjoy

That's great news & nice to hear members doing big favors like that on this friendly forum.

 

Glad to help a fellow KLX junkie. Enjoy !

 

Thanks Graham! Im stoked, its incredible how much of a difference 43ccm makes!!
Now I just need some exhaust mod

 

What does your plug look like?

 

Hey Nik, while a complete system is the way to go, if you can only do a slip-on right now, get a FMF PC4 or Q4... That way you can upgrade to a FMF header ( Either PowerBomb or MegaBomb) later on without fitment issues... That sound like a good idea?