New to forum, need advice

I am new to the forum and need some advice. First a little bit about myself, in the late 60s and 70s I was a motorcycle mechanic, factory trained Yamaha, Kawasaki, Suzuki, Triumph, KTM, CanAm, Husky, BMW, just to name a few. I raced flat track for many years, did some road racing, and still do my best to tear up the back roads with a Kwak ZX10R. I still have a 75 Penton(KTM) Mint 400, a KTM 500 (2 stroke), A ZX12 and the 10. So much about me .

I have a Cycle Factory flat track frame with Kosman wheels, Ceriani road race forks, Champion Glass, that I want to make into a street bike and maintain the classic flat tracker look. I am and was a Kenny Roberts fan. So I was thinking to put a Yamaha motor into that frame and the perfect motor would be the 450wr. Electric start, wide ratio gearbox, something to loft wheelies at the flick of the wrist and paint in the traditional Yamaha yellow and black.

So here is the question, can I get a 450wr motor anywhere, preferably used up and needs rebuilding or am I going to have to get a crate motor? And does anyone know of any sources of motors aside from going to a Yamaha shop and getting hosed down?

Thank in advance,

Some times E-bay has them as kart motors.Be hard to check it out unless it was close to you though but for the right price I guess it would work.

Beyond the crate motor option, I'd have to say eBay as well. I can't recall seeing any for sale here. It might be a good idea to peruse the classifieds just to get an idea how often they pop up and what they go for...SC

+1 on classifieds. Watch here and a certain supermotojunkie forum (SMJ). I won't link due to respect for this board. When guys really wad their bike up, they will sometimes part them out. The road guys seem to do it more often than dirt because of cagers on the road. I have seen a couple of mills go for a decent price.

Google "parting out WR4XX" 00,26,50

Good luck.

Well I found a donor bike a 2007 WR and the bike is now built and came out very well. I decided to restore the paint and it is close to perfect, the motor fit perfectly and the bike looks like a flat tracker and the street stuff is almost invisable. But I was very disappointed in the performance so I read through the forum and found a thread about improving it. I pulled out the spark arrestor and got rid of that tiny little pipe. Good difference. I have not looked at the throttle stop yet but I think the former owner already got that fixed.

I was wondering if there is a grey wire mod for the 07. There seem to be conflicting views on if there is. Does anyone know for sure if there is a timing advance mod?

Yes, there is a Grey wire on a 07.

There is also a air box snorkel to yank out, along with air box cut outs. Make SURE the PO did the throttle stop. You will need to re jet as well.

If you really want it to scream, get a good pipe, and cams, either YZ exhust, or Hot Cams, but if you go the YZ cam route, you may have e-start issues.

You can find endless threads on here to wake the motor up to what it should be.

Oh, did you yank the AIS yet? Of course if you have this on the street, a lot will depend on your local law for the pipe selection, AIS, etc.

The air box is completely gone and there is a K&N on the end of the carb, this engine is in a Cycle Factory flat track frame. I looked at it today and the throttle is done it opens the slide all the way, the AIS is gone and there is a plate covering the hole. If I am going to have e-start problems I will forgo the cams.

I found several threads on how to wake the thing up but the grey wire on an 07 was still up in the air. I want to keep it quiet as possible but a good pipe may be in order.

I had heard that on the 426WRs one could advance the intake cam one tooth and it would be like a YZ. Nothing like that on this?

The 03 and up 450's have a auto decomp cam, which is why you can have e-start issues with the YZ cam's, and I'm pretty sure you can't time it any different either, like you could with the 426's, but there are folks on here that would know more about that on here then me.

The Hot Cam's however, will not give you E-Start issues, as they have the correct decomp pin. I have Hot Cam's in my 04 and e-start work's great.

I have NEVER heard of a 07 WR in the US NOT having a Grey Wire

Does anyone have the definitive answer about what the gray wire does? It sounds like it is a rev limiter enable. Some seem to think it changes the advance curve. Is it one or the other or both?

Does anyone have the definitive answer about what the gray wire does? It sounds like it is a rev limiter enable. Some seem to think it changes the advance curve. Is it one or the other or both?

It's both.

The gray wire sets the CDI to YZ style timing. Just unplug the gray wire and try it, if you aren't happy with it then plug it back into the connector. Just be sure to tape over or heat shrink the end so it doesn't ground out on you. You may also want to disconnect/remove the neutral start wiring as this wil have the CDI in a neutral rev limiting mode which some believe also retards the timing of the ignition. It's all stuff that is easy to plug back in if you don't like it. WR Dave

Ted - After three years of teasing, no pics:bonk: What's up with that?

Pics please!

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