How reliable Wr400 bored to 460cc


Looking at buying a WR400 supermoto that has been bored out to 460cc when it had a rebuild. Is this pushing things a bit, or will this engine cope with this amount of tuning?

I will be using the bike on road.

how much is the boring kit and mods to make it run again. I have a wr400 and am interested... Thanks.

Sorry, got no idea mate. Looking at buying the bike with the work already done. Bit of a wally when it comes to mechanics, i have chosen my friends wisely though!!

I am by no means an expert but I just rebuilt my 400 with the OEM 426 parts, cylinder, piston, crank etc. But if you look at the rebuild kits offered by the most notable ones (Maxpower etc)....they take the 400 to 420CC, the 426 to 440CC and the 450 to either 470 or 490. I would question any kit that took a 400 to a 460 :thumbsup:

My two cents.

AGREED ......dont think there IS a kit to 460cc for the 400 ....some ones spinning you a line me thinks :thumbsup:

wel, i have asked the guy what kit he used. So we will se what comes back.

Think i might just buy the 625smc i was looking at aswell anyway. Sounds safer!!

frostbite has the 430 kit and recently cracked something in the head, but his environment is not what you'd call average and possibly contributed to it.

he has had it for a while i believe. may pay to summon the snowman.

My WR was a a 444 with a 426 rod. It seems to run fine. The WRf is a reliable motor.

KTM 625 is a much larger bike ...big time low end power but vibrates like krazy. Good for short rides.

just had the response back from the dealer. He stated that it was from an offical yamaha dealer and fitted by a proffesional.

not sure what to say???

sounds like he's running around giving you a straight answer... Beware. Theres a lot of bikes out there.....

Would it be best to ask him what kit it states on the reciept?

I would be cautious about that bike. If the guy doesn't want to give you a direct answer (not giving the type of kit as you asked) that should be a red flag right there. I also have never heard of a 400 being punched out to a 460. The things to keep in mind is that the crank has to be able to handle the extra power. If it has a 426 crank you are better off, but I still would be careful. Another thing to keep in mind is that you have a thinner cylinder wall now, AKA a weaker wall. That's my two cents.

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