450 single motors, 400 frame or bigger?

[miller]

Has anyone done anything with a 450 based single? This is a dirtbike frame and swingarm, looks good right? But due to cost you could almost chuck the motor into a much cheaper frame, maybe a an 87 1000 frame with the downtubes would work perfect I think..

[haunter]

when I had a 400 frame 'laying around' my buddy was trying to get me to get a 350 2stroke thumber to put in it......

sounded like a great way to kill myself!

[miller]

get this...

[haunter]

sick!!!

[miller]

And these motors can make a reliable 50 hp, or 65 in race trim.. you can rebuild and split the cases on these very quick also..actually the honda ones are so cool, with separate oil for the tranny and engine/crank side (keeps the clutch fibers and gunk out of your main bearings and top end), a single cam and rocker arm for the ex, buckets for the intakes, pretty bullet proof 4 valve design....

[abs929cbrrr]

450 motors are not realible. once you need a top end it will run ya about $1500. trust me, unless you have tons of cash to keep rebuilding a 450 motor you wont call it realiable. put a xr650 or xr400 or xr600 motor in there it will run forever, but do not use a new style hard hitting 2 stroke wanna be 4 stroke motor.

now go do what ya want haha.

[yamaha_george]

get this...
[

Miller,
That looks like a ROTAX thumper crammed into the frame ?

Singles in the 400 Alloy would be nice HOWEVER they do tend to be tall sump to head wise so some angle may have to be used with resultant oil flow problems although the airbox will not be there so maybe just maybe

[miller]

Nah its not a rotax, i have one in a trx running over 55 hp, its reliable but you have to get the right springs, and no its not for sustained high rpm use. I get about 40 horses at 6,000 rpms, 50-55 spread out over the last 3,000 rpms...36 lbs of torque, hits the dinger at 11,200. I have friends with over 60hp

Not sure who has to pay 1500, but i have this kind of stuff laying in my shop thats useable,i build 450 flat track motors on the side, the dealerships and their shop rates can see you coming abs "trust me". (plus i can get new honda head with an marginal 3 angle valve job for less than 200) But the biggest plus would be how easy it is to work on.

Not going to build one anyway, but it would be a fun little bike if you had the junk laying around, it would be a great short commuter.

[YAM93]

yeah, that first one you posted is actually a YZ450F motor AND frame, with extended custom subframe and plastics. Not sure about the fork, probably off an R6.

ABS is right though. Not something you'd want to be re-building all the time, but hell, if you found one cheap, for fun it would be cool.

[Luke-a-Tron]

A girl I know had some sort of custom built chopper some with giant single cylinder engine crammed into it (I don't really know much about it). I rode it once and decided that a thumper is far from ideal for street use. The power is just delivered too abruptly with a very noticeable lurch every time the cylinder fires. It was fine for the cruiser but it would be nerve racking on a high strung sport chassis when you're leaned over. I bet a 2 cycle would not be so bad since it fires twice as frequently though.

[megaloxana]

I just wanna ride that thing. Looks like a blast.