stroked and bored 426

[hontrx265r]

I'm in the process of boring and stroking my yzf426 just curious if anyone else has done this, and your thoughts on it. going to 2mil stroke and 2mil over bore, just under 460cc

[hontrx265r]

68 views and no one chime's in, I expected at least jrspawn had seen this done no one? I will take pics and keep everyone updated. Crank gets there monday and cylinder this week as well

[jrspawn]

Ive had and done a few stroked 426's and didnt really think the bang for the buck is there. And reliabilty also became a factor. I think my last stroked/bored setup was actually a 468(made from a 426) and i could honestly ride a stock 426 alot better on the track. You will find your actuall power curve is going to be different than the normal 426 or even a bored only 426.

thank you
justin

[hontrx265r]

I'm really building this motor more for the dunes and playing around with, I have another 426 complete bottom end with just a high comp piston to put my head on and run, at the track. Or ride my c-dale.

[timsmcm]

jrspawn will the 426f motor compete on the track with the crf motored hybrids i race against some crf hybrids and I need to build somthing that will compete I have a 2000 yzf426f bike with less than 4 hours on it , I bought it new to make a quad but have not done it yet

[jrspawn]

Originally posted by timsmcm
jrspawn will the 426f motor compete on the track with the crf motored hybrids i race against some crf hybrids and I need to build somthing that will compete I have a 2000 yzf426f bike with less than 4 hours on it , I bought it new to make a quad but have not done it yet

Compairing the two engines in that aspect is near impossible. It really comes down to the rider. I will say this though. the YZ426(400,426, and 450f) engine is prob one of strongest most reliable hybrid engines out there. They have more than enough power to smoke any 450 or even open class engines with a decent rider comparison.

Alot of people always say the CRF is superior, in my opinion, its not. Both yamaha and hondas are great engines, and different riders like different brands, thats what it boils down to. To each their own i guess. From my personal exp. with about all the quads and engines both production and hybrid, well theres a reason i like to stick with my little ol 426's and 450fs:devil:

Thank you
Justin

[timsmcm]

do you think the 426f in stock form is capable or do you think some things can help it like boring, different weight flywheel, or other engine mods? I am racing a 400ex now and dont have quite the power I need to compete, I am equal in every place on the track except for the long straights, where other newer powerplants pull away from me. My 400ex is setup as good as it can be it is just a little too heavy and a little slow

[hontrx265r]

I can say the last hybrid I had, was a stock bore and stroke 426 with a high comp piston, cams and a mild port. I was out at the dunes racing some equally modded bikes but 450 (yfz's and trx's) I had no problem smoking them down the drag strip. I had guys asking me what the hell i was riding (lots have no idea what a hybrid is) when I told them I was running an engine that was nearly 25cc smaller they were astonished. The other thing about it is that I was way over paddled so they were pulling me off the holeshot, and I would catch up and walk away in less then 300ft.

[timsmcm]

the only thing I need is to get to the next corner or hit that short jump with 20 feet of work room on the mx track light motor lots of quick torque. you know what I mean

[woodsracer144]

Originally posted by jrspawn
Compairing the two engines in that aspect is near impossible. It really comes down to the rider. I will say this though. the YZ426(400,426, and 450f) engine is prob one of strongest most reliable hybrid engines out there. They have more than enough power to smoke any 450 or even open class engines with a decent rider comparison.

Alot of people always say the CRF is superior, in my opinion, its not. Both yamaha and hondas are great engines, and different riders like different brands, thats what it boils down to. To each their own i guess. From my personal exp. with about all the quads and engines both production and hybrid, well theres a reason i like to stick with my little ol 426's and 450fs:devil:

Thank you
Justin

so just to make sure that i read your post right your saying that the 426 is runs stong and is one you can count on... but even tho the crf is a 450 the 426 will stick right with them....

im just makein sure because i have a 250r chassie... or i will in aweek or so and i have a ESR 265 power valve that im thinkin about selling and i'll need 500 buck more that what i would be selling it for to get this 06 crf 250(its mostly stock) and yeah i knwo its a 250 not a 450.... just woundering if i made a 4 banger out of my quad what to run... thanks