450 motors

[YFZ450]

Will the YZ450f or the WR450 motor fit ina yfz 450?

[Stoopidbot1]

I would say yes, with a few modifications.

[YFZ450]

like what mods.?

[Stoopidbot1]

Most likely you would have to fab different motor mounts.

[YFZ450]

all of the mount or just certain ones?

[SunLrider]

depends on where the engine fits in

[Stoopidbot1]

all of the mount or just certain ones?

You would have to see how the motor fits in the frame. You would then find where the motor mounts on the motor are and then weld some tabs to mount that motor to the frame. I've seen plenty of people do it with the CRs so I don't know why the Yammies wouldn't work.

[YFZ450]

OK i have a 06 yfz450 motor that has a hole in the bottom end by the shifter shaft and i know 04-05 yfz has 11:9.1 comp and the 06-08 have 11:4.1 if i where to use a 04-05 bottom and and mate it with my 06 head and use my 06 piston would i get the 11:9.1 comp or would i have to use the 04-05 piston?

[adammiles]

good question!! i think the bore, stroke and head are the same, i think it was a piston change.. not for sure tho. let me know what you find out its something besides the piston. just get an R6 motor if you have to modify motor mounts:biggrin:

[YFZ450]

i has to be something in the bottom end like the crank or piston b/c 04-05 yfz have 11:9.1 comp. with only a 439cc and the 06-08 have 11:4.1 with a 449cc. And the only thing i can think of is its either the crank or the piston

[YFZ450]

OK, im about to atempt my first rebuild i have a manual and everything i have to put a new hot rods crank in put all the new athena gaskets i bout a 05 yfz bottom end b/c my 06 is cracked puttin my 06 head on the 05 bottom end, how hard is this to do and when i split the case whats the best way to do so and will anything come flyin out at me?

[Stoopidbot1]

OK, im about to atempt my first rebuild i have a manual and everything i have to put a new hot rods crank in put all the new athena gaskets i bout a 05 yfz bottom end b/c my 06 is cracked puttin my 06 head on the 05 bottom end, how hard is this to do and when i split the case whats the best way to do so and will anything come flyin out at me?

Nothing should coming flying out. Lay it on it's side. It may sound like a pain but get a digital camera and take pics step by step. If you get lost anywhere you can just refer back to the photos.

[YFZ450]

which side should i lay it on the exhaust side?, I plan on taking pics for my rebuild/ racing video im goin to make with some kck azz backround music

[Stoopidbot1]

Do you have bolts on both sides of the case, or are they just on one side?

[jigolbeep]

i would probably go with clutch side up...

[YFZ450]

i found out how to thanks guys, the bolts are only on one side, so i would un bolt everything and lay it on the gear shifter side and and split the cases

[Stoopidbot1]

i found out how to thanks guys, the bolts are only on one side, so i would un bolt everything and lay it on the gear shifter side and and split the cases

Right on, good luck. Let us know how it goes.

[YFZ450]

The big deal is you have to remove a bunch of stuff just to split the case i think, like removing the a.c. magneto, clutch and some other stuff ect.

[Stoopidbot1]

I've only done it on a 2 stroke.

[YFZ450]

So i was taking the nut off the flywheel i had the motor on its side and all of a sudden i hear something it the ground i dont know if its a bearing out of the motor or what it about 1/4 inch round and i was thinking theres noy way a bearing just feel out of this motor nothing is lose yet all the gears are still together everywhere were theres a bearing everything is still tight i dont get it and if it is a bearing i would of known i would of been able to spin the crank or anything else you can spin to move the crank, its weird

[YFZ450]

So i found out what that ball was, i was looking in the manual for once finding out what it is and the bearing looking thing is on the inside of the clutch cover theres a pin that moves on a bearing and the metal ball rest on the end of that pin

[adammiles]

So i found out what that ball was, i was looking in the manual for once finding out what it is and the bearing looking thing is on the inside of the clutch cover theres a pin that moves on a bearing and the metal ball rest on the end of that pin

wait until it come times for the shifting mechanism, drum and shift forks... good luck.. are you uing your 06 crank, cylinder and piston??

[01 RAPPY 660]

sounds like it was the bearing behind the prussure plate and in front of the push rod right??

[YFZ450]

yea it was that bearing no biggy, im use 05 bottom end with a hot rods stroker crank with my 06 jug, piston and head

[YFZ450]

I got the whole engine apart,really easy if you have the smarts it isnt that hard. Ill post pics sometime soon of the engine apart and ill post more as i put everything back together

I only ran into 1 problem the bearing on the balancer one of the bearings is missing and it got chewed up in the motor i found all peices and blew them out and cleaned everything really good, im just wondering if i should get a new bearing because its only 1 small bearing that missing its like 1/4 inch long and 1/8 inch round

[YFZ450]

[YFZ450]

How do you get a bearing out if it doesnt slide out, i know you have to freeze it when you put it in, so would i have to freeze it to get it out?

[YFZ450]

I got everything back together, i lined up the fly wheel and put the cams in time everyting is on all is left to do is put the clutches back in and put the clutch cover back on then bolt it back onto the bike.

I was wonder if you crank the motor using a socket and its not in time can you bend the valves if its not in time because i cranked the motor and it sounded smooth i could hear the compression.

[YFZ450]

I may have said it before but i have a 05 bottom end and a 06 hjug and head on my 06 yfz450 got everything back in and started it today it started right up but i heard a tapping noise i think its the valves they may need ajusted, the motor has a new hot rods heavey duty crank which is 1.4mm longer than the stock rod and its im time the bike rev no other.

also another problem i have now is the clutch has alot of free play when i sqeeze the clutch it goes back out some and i have push it out the rest of the way does anyone know if the clutch cable is shorter or longer on the 04-05 to the 06-08 yfz?

[YFZ450]

I have a heavey duty crank in my yfz hot rods part No. 4062, does anyone know what the intake and exhaust valve specs are.