Motor Swap Options

[mechanic Sparkey]

Alright everyone, heres my sob story, don't know if anyones really going to care but it gives a background to my point.

Im a professional motorcycle mechanic and i decided it was time to rebuild my 04 stock YFZ. I race it regularly and locally, and I'm 18 years old without much money. So i did a basic build because I'm used to building drag bikes with my teacher this was realitivly simple. i just built a 14:1 compression motor with stage 3 hot cams and a jet kit. After building it i broke it in with one tank in my back yard (2 hours) then my girlfriend decided that she wanted to start an interest in this sport too, which was great, and i showed her how to ride my baby, and chalk up another 2 hours ride time...

okay, now my big mistake... my best friend has a raptor 660 and blew second gear out of his trans. i have the bike apart on my bench for no charge and i guess thats what friends are for, well i had work one day and he wanted to go out riding with a few buddies of ours, and i didnt see anything wrong with him using my bike... WRONG. he gernaded the entire motor. the piston let go, twisting the rod and actually bending the crank. the cylinder scored into the water jacket, 3 valves broke, 2 exhaust and the center intake, the remaining two intake bent. the transmission shattered completely. motors junk.

okay so now here i am 7 months later, i saved up just enough to get an 06 Yz450f motor slightly used complete with kicker, harness, cdi, and carb... shipped to my door. not bad if i do say so myself, now i searched all over the internet far and wide for months trying to find out anyone who has done this before and have so far only found one story of how impossible this dream is. He claimed that none of the motor mounts line up whatsoever and it cannot be done.

I am 15 hours into this build and so far have my motor bolted completely in, with only slight modification to the front mount and top mount. i have to move my rear shock back 1/4" and mount my new cdi somewhere still. i had to cut 5/8" off of my stock head pipe. and take out about a 1/2" from the stock kicker... the only thing i really have a headache from is that i am having a machine shop make me an adapter because the 450fs drive sprocket sits in closer by about 3/4".

so with all that i need to ask... AM I THE ONLY ONE? is there anyone else out there with this build done? is there anyone else out there who would be interested in this idea? factory claims about 17hp difference here stock for stock. sounds good for me still being able to run in a factory 450 class. also so far i have shedded about 40lbs of useless parts from the quad. if anyone is interested i would be happy to go into detail how i did anything and everything, i have some pictures upon request too, and within the near future i will be able to get anything photographed because i will be stripping the bike down after this mock up and sending everything off for paint!

thanks for your time, im bored and tring to see if anyone else would be interested in my madness, please do not hesitate to ask questions, i wish i had someones help when i started this. ill give out my email to anyone looking for help.

~Sparkey #127

This post has been edited by mechanic Sparkey: Jul 7 2009, 07:14 PM

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[yfz_guru]

well i guess i logged in at the right time lol, the spacer i had to build for mine was 17mm thick the lower engine mount is the only real correct one as you noticed and and the front and upper engine mounts need reworking i did 2 of these swaps and like you notice they are quite a bit lighter as for the cdi mount i managed to route the wirring from the left case, in front of the cylinder, up the front right engine mount, under the rad above the frame and made it fit











This post has been edited by yfz_guru: Jul 7 2009, 07:40 PM

[mechanic Sparkey]

very interesting! its great to see someone else has accomplished it! gives a little more hope haha.im haveing the machine shop make me an add on to the trans shaft spacing it outwards rather then spacing the rear inwards i just wasnt too crazy about the chain on the swing arm. how does yours run? was it worth it haha? and also would it be asking too much to have a picture of your wiring. i cant seem to find anywhere to put it.

[yfz_guru]

there is a picture of how the wiring runs along the engine mount i will get better ones tomorrow night

[mechanic Sparkey]

ah i see okay, haha im sorry its late and i didnt look that closely, thanks!

[crooks]

The front motor mounts and front sprocket are the only major differences on mine.










white is stock black is yz

[mechanic Sparkey]

thank you very much! i have changed pase a little though and sent out some of my rear end parts to be machined and have a spacer made

[blackhilljack680]

hey there just bought yzf450 motor an 06 and got it bolted in perfect and ran all the wire now i just am haveing trouble with the chain i seen the recent posts and would like to kno where and who did that for them ill be willin to pay good money for a rear sprocket spacer or a front sprocket spacer just p.m if u wanna take me up on my offer i just wanna get this thing back on the dirt thanks

[mechanic Sparkey]

My long time friend's father owns his own machine shop so he is doing all my work the best I could do for you is get all the specs I have written down tomorrow. And when I get everything back takepixtures. I'm spacing my rear sprocket 1/2" to the right to make it line up. I have all the specs for making a shaft spacer upfront that would even allow you to still change sprockets on the fly but I don't know anyone with access to a spline machine so I'm sol there and that's why I'm not going my prefferred route. So tell me what you would rather and I'll do it best from there also where are you located? I'm from fairless hills pa

[YFZracer61]

Don't want to steal your thread, but I have a similiar question.

I ride s 250r hybrid with a YZ motor. I want to put in a YFZ bottom end for the E-start. All that would be required, is new front mounts, and to offset my rear sprocket correct? The mounts are no problem for me to make. and I can just move my rear sprocket over by 3/4"? Is this all I need to change?

[Husker525]

What is this? 'Chop, Cut, Rebuild'???? LOL, Actually, I think it is very cool that all of you have such out of the box thinking when it comes to fabrication. Anything can be fabricated, with enough time and materials. I started out with a hybrid 3 wheeler, and I was hooked from then on in fabrication.

[crooks]

Don't want to steal your thread, but I have a similiar question.

I ride s 250r hybrid with a YZ motor. I want to put in a YFZ bottom end for the E-start. All that would be required, is new front mounts, and to offset my rear sprocket correct? The mounts are no problem for me to make. and I can just move my rear sprocket over by 3/4"? Is this all I need to change?

Why would you want to do that? Are you having a hard time kicking your quad over?

[mechanic Sparkey]

yfzracer, i dont think i follow that idea, also im not too sure if the 426 cylinder will just bolt right up, also are the main bearings the same and whatknot. you must check with a dealer or online part lookup and make sure the part numbers are all the same. in addition to that you shouldnt need a new crank or anything just the side case with the onewayclutch and all the gears right?

[YFZracer61]

nevermind the intermixing parts, ive got that taken care of. i meant physically putting the 450 motor in there. Making different front mounts, and just offsetting the rear sprocket right?

[crooks]

Why would you go to a yfz motor?

Only people that have your frame are going to be able to tell you exactly what you need to do to fit that motor in it.

[crooks]

My long time friend's father owns his own machine shop so he is doing all my work the best I could do for you is get all the specs I have written down tomorrow. And when I get everything back takepixtures. I'm spacing my rear sprocket 1/2" to the right to make it line up. I have all the specs for making a shaft spacer upfront that would even allow you to still change sprockets on the fly but I don't know anyone with access to a spline machine so I'm sol there and that's why I'm not going my prefferred route. So tell me what you would rather and I'll do it best from there also where are you located? I'm from fairless hills pa

Instead of having to cut the splines yourself why not just get a blank sprocket then space it out and weld a standard one with the splines cut out to it. I believe this is how mine was made.

[YFZracer61]

Why would you go to a yfz motor?

Only people that have your frame are going to be able to tell you exactly what you need to do to fit that motor in it.

for the electric start. im 135 and kickstarting a 450 sucks. I can do it, but id rather have the electric with a kicker backup.

and I have a spare ported head, and a big bore yfz piston and cylinder to go on my new bottom end.


thread hijack over. ill ask on the hybrid forums.

[crooks]

Do you wind the kicker up to TDC then kick? Or do you pull the kicker out and start kicking as hard as you can? My friend is 140 pounds and has 1000cc harley and xr650 both kick only. With a tuned carb it shouldnt be bad I can start mine sitting down.

This post has been edited by crooks: Jul 13 2009, 07:01 PM

[YFZracer61]

TDC. I stand on it, and jump downwards. I can start it, I would just prefer the electric. and i dont race mx or anything, so 10 pounds doesnt mean much to me.

[blackhilljack680]

im looking to go with the rear sprocket spacer but it really dont matter what ever can get it i live in millersburg ohio my email is yamaharider680@aol.com if u wanna email spec to me thanks for all ur help