YZF750/1000R - The Fly

canyoncarver

'hacking is learning'
I've owned my share of different bikes over the years and although I've ridden a few supersports, I've never owned one. For the last 15 years, I've been very happy with the ZRX as my comfortable hooligan daily and sport touring machine. I also have my Shovelhead Harley chopper and for fun I'm building a cafe style KZ750 twin but I was still missing one.

Early last year I ended up with an interesting 1994 YZF750R project. It came as a disassembled project from the PO but it has a title and instead of the 750 motor, it came with a later model 1000cc Thunderace motor and a rack of FCR41 carbs. The 1000 motor is only about 20mm taller than the 750 at the heads so with very little work the Ace motor bolts into the 750 chassis and this one is already modified for it. Very cool. (yes, a 750 motor still fits my chassis...nice option to have). The PO didn't have much info on mileage or history on this particular Ace motor and the chassis needed misc parts and plenty of sorting so I stuck it in my shed and thought about it awhile. A Yamaha Genesis EXUP 20 valved inline 4 supersport classic.

Timing is everything. After lurking Craigslist long enough, a wrecked 97' YZF750R parts bike showed up and I pounced on it. The frame on the neck is cracked and the forks are likely whacked but the bike went down with only 4129 miles on the speedo and lived in a shed since that day. Other than forks, plastics and tank, it is basically complete and in good shape. I bought the right service manuals and it's time to move forward. For the curious, I'm just under 800$ including both bikes and the manuals.YZF_books.jpg
 
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canyoncarver

'hacking is learning'
I'm starting to go through the chassis and make notes on needs vs wants.
For instance, the 97' will have a better rear shock so I'll need to swap that out.

Really happy I now have two full electrical harnesses to pick from, the original is in pretty good shape, doesn't seem to be molested.20170306_202119.jpg
 
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canyoncarver

'hacking is learning'
These have a super simple bolt on subframe, no need to modify anything.yzf_subframe.jpg
 
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canyoncarver

'hacking is learning'
clem said:
Should be awesome. Do you see any large obstacles in front of you with this one?

Glad to have you and Jussy onboard! BTW, I'm the only large obstacle getting in the way....
 

canyoncarver

'hacking is learning'
Two more, you guys are quick, welcome aboard. So...I'm thinking I should try and fire up the 750 parts bike just to see what I get before I tear into it. I'll need to do a quick clean on the carbs and a bypass of the ignition switch but otherwise it looks like it's all there. I'd like to know if the low mile 750 motor is good to go just in case..
 

canyoncarver

'hacking is learning'
JSJamboree said:
Im in for this, im sure it'll be a long build but Im excited to see it come together.

Right on!. Your builds are excellent, glad to have plenty of experienced heads with me on this.
 

teazer

Active Member
DTT BOTM WINNER
That's a killer deal you got there and piles of spares. 41s a are just a touch on the large side for a 1000 and huge on a 750, so that means big bore kit is needed and hot cams and.... oops. There I go again. And I told my therapist I had that under control. Ah well.

Stock carbs are 38mm CV (I think) which is about the same as a 34 slide carb.
 

hillsy

Active Member
From memory the Thunderace had the same frame as the 750 (they slightly modified it at the rear), so the engine swap is fairly easy.


If those tanks have fuel in them and they have been sitting then the fuel pumps are probably stuffed (they sit in the bottom of the tanks). You can easily adapt an external low pressure pump though.


Nice score - my brother in law still has his 750 after many years and he still loves it 8)
 

canyoncarver

'hacking is learning'
teazer said:
That's a killer deal you got there and piles of spares. 41s a are just a touch on the large side for a 1000 and huge on a 750, so that means big bore kit is needed and hot cams and.... oops. There I go again. And I told my therapist I had that under control. Ah well.
Stock carbs are 38mm CV (I think) which is about the same as a 34 slide carb.

That's what I was thinking, big. I don't know if anyone's been inside the 1000 motor but reasonably certain the 750 hasn't been modified. Also why I should try and start the parts bike motor first. The FCR's are a little crusty but will clean up really well. No airbox or stacks for them either.
 

canyoncarver

'hacking is learning'
hillsy said:
From memory the Thunderace had the same frame as the 750 (they slightly modified it at the rear), so the engine swap is fairly easy.
If those tanks have fuel in them and they have been sitting then the fuel pumps are probably stuffed (they sit in the bottom of the tanks). You can easily adapt an external low pressure pump though.
Nice score - my brother in law still has his 750 after many years and he still loves it 8)

Thanks Hillsy.



Yes, both tanks I have are crap inside and missing the pump and lower covers. I think the black tank (relatively undamaged) should clean up. I was starting to read about the fuel pump options too. I'll need to figure that out.
 
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