What do I need to do? to beat a 450....

[jimi]

Im setting it up for MX and I can build motors, just need a big bore kit and pipe, carb. Im looking at CT, or ESR? I have had a built motor from Duncan racing but it was on a LT250r. I liked it. Im thinking ESR....

[Saber569r]

Im setting it up for MX and I can build motors, just need a big bore kit and pipe, carb. Im looking at CT, or ESR? I have had a built motor from Duncan racing but it was on a LT250r. I liked it. Im thinking ESR....

Esr builder kit probably your best option, the builder kits would be a good set since u can do you own work. My Esr 330 was about a quad legnth slower than my 350 but that was the basic port job trx 9.

[aberegg05]

Wanna go fast? You need a BHP 363.

[Wrench U]

I'm sorry if u take this the wrong way, but your setting it up for MX and your worried about motor! Rockets only fly straight, last I remember is mx ain't straight. Power + traction = accelerate the more the tires stay in contact with the ground the faster u will go. There is more to making a bike fast on a mx track then HP. Lots of good info out there about putting together good package for the track for dirt bikes that applies directly to atv's. IMO.

[Saber569r]

For mx led, c Leigh racing are real good but never ran there stuff so couldn't tell you for sure.

[kb250r]

I run all Neil Pritchard built and ported engines and they are no joke let me tell ya.. But in the off season I'm sure he is wide open like everyone else and got cylinder lined up for porting..I'm with wrench, on power + traction seams like a stump puller 295 or 310 on race gas with about 230 compression would have that stump pulling GRUNT for mx....

[rablack21]

Im setting it up for MX and I can build motors, just need a big bore kit and pipe, carb. Im looking at CT, or ESR? I have had a built motor from Duncan racing but it was on a LT250r. I liked it. Im thinking ESR....

This is just my personal opinion from racing mx against the 450's. A built 310cc motor will get you mid pack. You will be faster than some 450's, and you will be slower that the built 450's. A built 330 will get you in the top 5, very close to neck and neck with built 450's. A built 350 or even 363 stroker motor will get you past the built 450's (not all of them but the vast majority). A 350 or 363 stroker motor gives you enough power to surpass the 450's, especially in acceleration. So it really just depends on where on this scale you want to be and how much you want to spend to do it.

[jimi]

I'm sorry if u take this the wrong way, but your setting it up for MX and your worried about motor! Rockets only fly straight, last I remember is mx ain't straight. Power + traction = accelerate the more the tires stay in contact with the ground the faster u will go. There is more to making a bike fast on a mx track then HP. Lots of good info out there about putting together good package for the track for dirt bikes that applies directly to atv's. IMO.

I got that worked out, PEP set up for me, Tires, and nice wide ride, I just want to get in there and not just look good but want to go.

[jimi]

This is just my personal opinion from racing mx against the 450's. A built 310cc motor will get you mid pack. You will be faster than some 450's, and you will be slower that the built 450's. A built 330 will get you in the top 5, very close to neck and neck with built 450's. A built 350 or even 363 stroker motor will get you past the built 450's (not all of them but the vast majority). A 350 or 363 stroker motor gives you enough power to surpass the 450's, especially in acceleration. So it really just depends on where on this scale you want to be and how much you want to spend to do it.

Thank you that is what I need, a built 350,,, I will do the rest.

[etccb]

Or the 363... There is some good usable power that comes with a stroker crank. 350 is good but there is more there with the 363 and although some people may say it is not needed at that cc a power valve will also give you even more at the lower rpm.

[Saber569r]

There's a guy on here who runs a 363r mx, I think it's burns363r or something like that. Id try pm'ing him he'd be able to give some good advice.

[rablack21]

There's a guy on here who runs a 363r mx, I think it's burns363r or something like that. Id try pm'ing him he'd be able to give some good advice.

Yes, Burns is a good resource as well. But I believe he will tell you the same as what I said as he and I have discussed this in the past, before I built my 363.

[Robsessed86]

I say go 363 sphinx ported by a known big bore builder. I have one ported for mid- top and its a real beast. I've raced several 450's both close to stock and built and haven't lost a race to any 450.  I used to have an Esr 330 stroker which was a strong contender against most 450's but not all. My sphinx would eat my Esr 330 for sure along with built 450's. That's my 2¢

[jimi]

Im going to build a 350 ESR, I think. looking at 2500 to start and see were we go from there. would buy a built 350 if it chepper but I see there all around 2500 and I kinda want to have the FUN of building my own beast.

[kb250r]

Esr 350 builder kit cylinder,piston,head,dome everything for about $650.. port work $350 ,carb $200, pipe $3-400 case boring $75-100..man that's only about $15-1600 buck you will still have money to burn. Enough left over for that +4mm stroker crank $250... Oh yea stroker baby...!!! ��