09 kx250f motor work.

guys i have a 09 kx250f with 75.3 hours on it from when i bought it brand new. everything is OEM and i havent touched the motor. i have checked the vlaves every 10 hours and they have not moved from factory specs, i know this casue i keep record of them when i check them. the carb is all stock too. i have only added a uni ait filter. im soon gwtting another job, maybe 2 for a short period of time till summer, then ill only ahve 1. but i am planning on sending my motor out somewhere to get modded. im looken for the low end power, simular to a 450 but not that much. im looking to get SS valves/springs. im thinking a big bore kit but not sure who does good work. i dont wanna go to big on the bore tho. maybe 30cc at the most. BTW i do harescrambles/woods riding.

anyone?

slow down grass hopper, its only been 3 hours. A big bore kit does sound like its right up your ally from what you have posted.

Put the beer down

if the valves are fine, don't bother with SS valves, waste of money, and you'll loose some performace, really engine mod's are pointless on these bikes without going for suspension first, at 72 hours your well and truely due for new fluids in the forks and shock, and prehaps evan new bushes in the forks, then look at a revalve and 22mm offset clamps (makes the bike handle much better), and after that look at engine mods.

don't evan bother with cams or exhaust's, the gains are minimal at best, the best back for your buck is to get the head ported, i don't know who's good in the U.S, PM D-K, he's got alot of the info, next would be a high comp piston, but again the gains are fairly small and i've found it's only once you get into race gas compression ratios that the differance becoems noticable.

At 72 hours a fresh top end will give you a noticable HP gain. As the piston and rings wear you gradually lose power and then when you throw a new piston in there it's back to like new power.

Porting would be a very good option. The horsepower gains are far more than adding a pipe and way cheaper too.

well i just got my head back from yosh, and i rode the bike 3 times bike has more roll on power but lost that snap kaw is known for, i rode my friends stock one that i put my yosh pipe on and i like the one with just the pipe better, so pipes do work at least the yosh!!!!!!! i'm putting a pipe on this week so i will report how it feels with the porting. A big bore is the way to go cylinder works has a 270 kit at a good price.

well i DO have the whole suspesnion kit for my bike right now. i agree suspension comes first.

add a pipe and maybe a hotcam...you start hopping up your motor a bunch and your asking for trouble...and you gotta run race gas...which is ridiculously expensive...but it is your bike so you can what you like...I guess if you dont mind running race gas porting isn't a bad idea

well i had a set of stg 1 hot cams in my 07 and ridght after that my valves went to hell. i think im gonna keep it all stock since that was my oringinal plan.

add a pipe and maybe a hotcam...you start hopping up your motor a bunch and your asking for trouble...and you gotta run race gas...which is ridiculously expensive...but it is your bike so you can what you like...I guess if you dont mind running race gas porting isn't a bad idea

You don't have to run race gas if you get your engine ported. You will probably get a bigger gain in performance than a pipe and its usually cheaper to.

Porting wont require race gas. what requires race gas is when compression is raised. either and or advancing ignition timing.

Unless they deck the head when its ported..... that could raise the compression.... but I def recommend the right head work or a big bore kit if your riding off road stuff and not mx. Cams sacrifice a little bottom usually so thats not really an option, and if you get head work make sure whoever does it knows what u want, more bottom, because most 250f head work increases mid to top. A piston will give it more snap but higher compression increases wear. I have an 09 with stage 1 Hotcams, a hi-comp Vertex, and a FMF 4.1 with the Megabomb. For what you wand I would recommend the Megabomb if you are going to get an exhaust because it gives it a lot more grunt. I've also had an Athena 290 kit in an 06 and I think that would work well for the woods but the way I ride I wasn't a big fan unless I was on a really tight track. The bike signed off a little early and I didnt feel comfortable bouncing it off the rev limiter. Whatever you do though as long as you keep it fresh and the jetting right your bike will rip! I hope that helped a little...

Get a new top end IMO. Cheap and good insurance. Also, power will be noticeably better IMO.

Porting wont require race gas. what requires race gas is when compression is raised. either and or advancing ignition timing.

porting changes the dynamic compression rato of an engine, which is more important then the static compression ratio for obvious reasons, although porting on a stock engine won't push it into race gas territory, if the engine already on the verge of needing race gas, and the porting is done jsut right it can push it over the edge.

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