'79 XS750 Yamaha Cafe Project

appiebroomer

Active Member
DTT BOTM WINNER
My current project so far. 18" front wheel from a XS400. 41mm VFR750 front forks. Alloy clip ons. RD350 headlight. Rear sub frame redesigned to raise seat height and lay shocks down at a 45 degree angle. Stock XS750 gas tank lengthened about 4" to give it that IOM extra capacity look. Stock XS750 seat pan shortened about 8". Using the stock XS750 seat tail piece.

20141013_162950[1] by albaljeu, on Flickr
 
Looking for one of these exhaust systems. A Kerker 3 into 2. Any body have one ?
 

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Got er done for now. I wanted to get it ready to ride in the Distinguished Gentleman's Ride. These triples have a real sweet motor, and have a very unique exhaust note. The 78 and 79 XS750's have a redline of 9 grand compared to 7500 for the 76 and 77's. Sure am enjoying this bike. Still need to give it a proper paint job, that will happen this winter.
 

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Whoa! Holy cow. That's the world's shortest build thread.


A LOT of work put in the bike there! How do I know, because it looks a helluva lot like mine except it's DONE! Congrats to you.

You have mentioned 18" front xs400 wheel with the FZR front end. Ducati wave rotors? Dual front disc brakes.

I'm running into difficulty with the rotor offset on my conversion. The center boss on the xs400 wheel for the rotor isn't deep enough to fit a spacer and the ducati disc without the disc left floating only on the mounting bolts to get the needed offset. Your wheel is also drilled both sides which I don't think all the XS400's were.
My problem is I used a busa front end and the sizes of bearings for the new front axle were not as heavy duty. Had to have the center bore machined on the wheel and of course new axle spacers machined.

Adapted sportbike rear sets with rear master. Foot position is almost exactly where I put mine at except I used a XS750 frame and had to weld my own mounts.

Nice reverse cone exhaust. I haven't gotten to that yet. Do you have a pic of the headers?

I swear that looks like a zx-10r rear Nissin caliper. I used the same thing! [EDIT- looking at my caliper and yours closely, it's different. Definitely NOT stock, though is it?] Looks like a custom rear carrier on a smaller diameter wave rotor? I spent my son's future tuition money getting my carrier adapter machined. But I used a zx-10r rear disc which is a tiny bit smaller than yours making the carrier design just a bit more involved. I like yours better as it looks like it would have been much cheaper to machine and gets the job done. Made your own caliper stay as well I see.

Looks like you kept the stock rear axle, right? Did you sleeve the caliper bracket or use on off the earlier gen zx-10r?

Those look like genuine Ohlins rear shocks! Me, too! What model did you get? Spring rate? Length? I went with the Vmax one if I recall correctly. Your's of course is at a different angle.

That subframe mod looked odd at first, but altogether, looks perfect! and better than mine. Stock, even with a rear that is raised a little on the rear shocks, it has a sloped back look like a chopper. A new rear subframe flattens the line nicely without resorting to running the shaft drive at a weird and destructive angle.

I didn't mod the subframe but did do some extensive frame bracing.

What tires did you end up using on the 18" rims? I went with the conti attacks. Can't wait to try them out.

Any engine mods?

Nice to see someone else as crazy as myself modding their triple. Better to see yours done. I'm going on two years with mine. Awaiting engine reassembly. Then looking to make a sportbiketracktime trackday next year.

contifront.jpg


rear%20carrier2.jpg
 
Nice clausing lathe in your flicker album.

I'm in the market and just checked out a Shledon lathe that is unfortunately a little too beat up. Had to pass.
There's my dream lathe nearby that I'm gonna check out. Hardinge HLV and a TC. If only I could afford it and figure some way to get it into my basement!

Right now, I'm using a tiny little 3 in 1 machine that has seen better days but good enough to machine aluminum spacers with.
 
A few more details. I'll post more pics if interested.

XS750 gas tank lengthened 3 1/2".
Stock seat tail section with integrated LED taillight, brake light and license plate light.
Stock seat pan shortened and narrowed, custom seat cover sewn on my 1958 model Singer sewing machine.
KOSO DB-02R digital speedo and tach unit molded into the OEM XS750 headlight bucket .
VFR750 41mm front forks and triples. XS400 18" front wheel.
Front fender is off a Honda CM250.
Avon AM26 Roadrider tires.
VFR750 Front brake calipers.
Honda SF400 front rotors.
3 into one header with an Emgo universal megaphone muffler.
Custom made fiberglass side cover/number plate.
Rear sub frame was redesigned to raise the seat height and create a more open look under the seat and rear wheel
and to accommodate the rear shocks angled at 45 degrees.
Rear shocks are fully adjustable for rebound and compression.
Rear brake utilizes a Yamaha R6 rotor, caliper, caliper bracket, master cylinder, modified XS750 caliper stay.
The number plate graphics are a tribute to my favourite Moto GP rider...9 time world champion Valentino Rossi.
 

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You mentioned the 45 deg angle on the shocks. Was that primarily for looks or is there a mechanical advantage to 45 deg?

I have to say it looks like it came from the factory like that. Which is a compliment, BTW.

Had to look up the Honda cb400sf. The bolt circle, center hole diameter are all different from the xs400/xs750 wheel. There must have been some serious work to get them to fit.

Same with the rear.

How 'bout Rossi. Showing the kids the fast way around after everyone wrote him off. I'm a huge fan, too! (though still think Lorenzo has the speed to win, it's Rossi's to lose)
 
jcw said:
You mentioned the 45 deg angle on the shocks. Was that primarily for looks or is there a mechanical advantage to 45 deg?

I have to say it looks like it came from the factory like that. Which is a compliment, BTW.

Had to look up the Honda cb400sf. The bolt circle, center hole diameter are all different from the xs400/xs750 wheel. There must have been some serious work to get them to fit.

Same with the rear.

How 'bout Rossi. Showing the kids the fast way around after everyone wrote him off. I'm a huge fan, too! (though still think Lorenzo has the speed to win, it's Rossi's to lose)

The 45 degree angle on the shocks was a design feature just for looks plus you get more wheel travel with the same shocks, and to allow for a higher seat height without having to use super long shocks and creating bad swing arm geometry.
The Honda 400SF rotors were the closest I could find with the proper offset, just had to bore out the center hole and enlarge and move the holes in the bolt circle just slightly. I wanted to use the VFR front end and calipers and the 18" XS wheel.

Lorenzo has the speed but not the consistency, I hope this fight goes right to the last lap of the championship.
 
Just read Lorenzo hurt his shoulder in a minibike accident

http://www.crash.net/motogp/news/223785/1/shoulder-injury-scare-for-jorge-lorenzo.html

He's playing it down but who knows...


Just put an offer in on the Hardinge lathe.
 
Sure like this KOSO speedo/tach unit. It will record 1/4 mi times, 0-60 times, top speed, top RPMs, has 2 temp gauges (oil and coolant) it also has telltales for signal lights, oil pressure, neutral, high and low beam. I molded mine into the headlight bucket. A reminder of my first bike a 1967 X6 Suzuki 250.
http://kosonorthamerica.com/product/db-02r-digital-lcd-meter-streetrace-version-4/
 

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LED strips for tail light brake light and license plate light
 

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