In two weeks, my local mx shop is gonna bore my 300EX to a 340. How much power gain will i experience and what about the reliability will i lose.

 

Hey I was just wondering, whenever you get all of this done if you can tell me what are the improvements over a stock 300. Also, what made you go w/ the dual rate shocks instaed of the triple rate ones? I'm not too familiar w/ aftermarket suspension, so what do the remote reservoir do to improve the shock itself? Also one last thing, what kind of quads do you race against? Are there like any 440EXs or 330Rs that you race against? If so how do you fare against them??? E-mail me at Mx300EX@aol.com

Til the next time we chat again, keep the Honda's out front.

 

man i hate to burst ur buble but in ur mods list u say for this weekend ".40" over bore.... it doesnt make it a 340!!!!!!!!! it might make it a 292 or osmething like that now.. soory man
matt

 

I race against 400exs and 250Rs and banshees and stuff. That is what i will be racing against when i start.

 

As mxer said, .40 will not increase your displacement by much. Going for a Wiseco piston vs. a Honda will do this for you: Wiseco's are generally lighter. The pins are lighter, you can use a Wiseco pin in Honda piston. This will make your engine rev quicker. Some of them increase the compression slightly. Make sure it is bored with enough tolerance. Wiseco's have a low silicon content. They expand a lot. Sometimes their suggested tolerances are not enough. The extra tolerance makes for a nice rattle when cold. Be extra careful warming it up. If you don't warm it up, you could crack a skirt from the slap or the piston can expand too fast for the cold bore and sieze.

 

Sorry guy but a .40 bore is basically a cleanup job for new rings to seat againt and true up walls.You may pick up 10cc at most.The gains you will see will come from a better cam and higher compression piston to match cam specs.Some head proting for improved flow is also recommended while it is down.The gains you see will be stronger low-mid with a huge increase in top end as well as a quicker revving mill.Go to GT thunder website to see dyno run he did on similarly modded engine against stock 300ex.Especially where the stocker signs off at around 6500rpm the modded engine continues to climb and make power all the way to 9k.Do it right the first time or you will be dissapointed with just a (cleanup) job.