'77 XS750 Brat/Tacker/Cafe Thing: Project "Intervention"

ejether

Active Member
I fell in love with the Yamaha XS750 triple because I love odd platforms and banging my head agains the wall...
I found one locally for $250 with 31K on it and the usual "Runs but hasn't been started in years" but I didnt' care. I just wanted an XS750 with all the pieces and a title. Mission accomplished!

My inspiration for the project is Classified Motos XS750 brat bike: http://johnryland.posterous.com/and-now-for-the-studio-shots
http://johnryland.posterous.com/1978-yamaha-xs750-special
Ewing_1035_FIN.jpg


I don't want to copy exactly, but I think they did a stellar job on the platform.

I want a little more cafe style, but I like the tracker aspects with the large diameter from tire and low handlebars.

My starting point:
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Where I'm at now:
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What I've already done:
I cleaned and painted the carbs and I got it started. It was a smoky beast. A valve adjustment later and its less smokey but still seems like it needs new valve seats.

What I plan on doing:
R1 front end swap (got and 05 complete front end for 250!)
K&N pods
chop and repaint the frame
3:1 custom exhaust
slim down and relocate the electrics to open up the frame
I'd like to upgrade the ignition but I'm not yet sure what my options are.
drill the rotors
repaint (of course)
and an as yet to be determined cafe/brat tail....
I'm sure I'll come up with lots of idea, and suggestions are welcome

Right now, I'm trying to decide if a complete rebuild is in order.
I need to pull the top end anyway, so why not hone the cylinders, and if I am doing that... why not pull apart the cases
It does have 31K on it... BUT the compression is good: 150,148,150

What should I do there? Complete rebuild, or just top end?
 
Re: '77 XS750 Brat/Tacker/Cafe Thing: Projecte "Intervention"

Right now, I'm trying to decide if a complete rebuild is in order.
I need to pull the top end anyway, so why not hone the cylinders, and if I am doing that... why not pull apart the cases
It does have 31K on it... BUT the compression is good: 150,148,150

What should I do there? Complete rebuild, or just top end?

[/quote] Well, im pretty sure your going to have to, ive rebuilt 3 motors from xs 750 triples and did 2 engine swaps. they all had something wrong internally. They are very smooth riding bikes. I am onboard for this build my friend.
Im working on a dt250 cafe racer right now.
 
Re: '77 XS750 Brat/Tacker/Cafe Thing: Projecte "Intervention"

The folks on the Yamaha triples forum seem to think I should be able to get away replacing the valve seats and the piston rings, as long as nothing else appears wrong.
I'll see what I find when I start tearing it down, but I think I've got enough info to get the engine out of the frame for now and start working on the front end swap and the chop lines.

Thanks Guys, I'm looking forward to this one!
 
Re: '77 XS750 Brat/Tacker/Cafe Thing: Projecte "Intervention"

If you have the budget and time, rebuild the engine, if not, give it the top end refresh. I've got an XS850 engine in pieces right now. Do you know if the bike has the 2nd gear fix?

I'll be watching the build. Front end swaps really change the look of the triples. I stuck to the original front end, but if I did it again, I'd probably swap it out.

Chain drive swaps are not simple on the 750. It requires relocating the engine slightly, modifying the frame, etc. It's possible, but I wouldn't do it unless you're OK spending the time needed.
 
Re: '77 XS750 Brat/Tacker/Cafe Thing: Projecte "Intervention"

I don't know if the 2nd gear fix has been done yet. I will certainly make sure it gets done.
I've got the time, and given the time and a steady paycheck, I've got the budget.... decisions decisions......

I don't intend to do a chain swap. I like the shaft drive, especially in Oregon where the possibility of riding in the rain/wet/puddles is likely and I hate cleaning chains :)


Are there any checks in general that I can for the bearing when I have the top off of it?
 
Re: '77 XS750 Brat/Tacker/Cafe Thing: Projecte "Intervention"

Where in Oregon are you? I'm in Eugene and will be following this build. I'm going a similar way with my yamaha xj650, brat/cafe-ish
 
Re: '77 XS750 Brat/Tacker/Cafe Thing: Projecte "Intervention"

fuggers said:
Where in Oregon are you? I'm in Eugene and will be following this build. I'm going a similar way with my yamaha xj650, brat/cafe-ish

Portland!

Working out of a small two care garage with 4 motos in it. Not much space when its raining out.... constantly!
 
Re: '77 XS750 Brat/Tacker/Cafe Thing: Projecte "Intervention"

I decided to purchase an NOS assembled valve head with the cams and valves in place all ready. Apparently has 25 miles on it from 1977.
It cost about as much as the tool to cut valve seats so I.

Since this is my first attempt at a rebuild, can anyone fill me in on an inexpensive way to get the machining done on a project like this.
Seems like getting it done is expensive every time, and buying the tools is expensive once.

Thoughts?
 
Re: '77 XS750 Brat/Tacker/Cafe Thing: Projecte "Intervention"

Made a little progress on the disassembly tonight.
Pipe, rear pegs, tail section, carbs all off.
Started to remove the wiring loom and rear wheel but its late and I decided to call it a night instead of breaking something.
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I've got too many irons in the fire, but I'm still chipping away at it.

Got the rear wheel off, the spline and gear look in really good shape!
Removed that ugly ass battery box (right in the bin) and got the rear half of the wiring harness off.
Caliper ready to be removed with the rear master cylinder and ready to be rebuilt.

Other stuff I working on (why I'm not making more progress):
Naked conversion of my GF's 2000 Triumph Sprint

7048170395_fccc9a8d61_z_d.jpg


Repaint of said bike. It went down with her on it a few weeks ago.
It broke the headlight, shifter and crank cover on the left side.
She broke her left collar bone. Both are on the mend now.

I'm busy :D
 
I'm looking around for rear sets and I'm thinking the Loaded Gun Customs sets on Dime City look pretty great.
Has anyone use a set of these on the xs750 and if so how did you mount them?

I don't see an easy way to mate up the rear brake lever. Is there something I'm missing in the linkage kit maybe?
 
R1 Front end mocked up.
Just need to get bearings for it.

I tried allballsracing but they said they didn't have a conversion kit for it. Anyone know what size I'll need?

6946657122_0ed5142e32_d.jpg
 
It's going slowly. I've been distracted with my GFs bike but I got tires, and the bearings for the fork swap on order. Once this bearings arrive, and I get the tires mounted, I'll start lining thing up for frame mods and look for rear set placement and seat shape.

I'm making progress, slow but sure! Thanks for checking it!
 
Damn!
It's been way too long since I've had a chance to work on my project. But I finally got the motor out of the frame! Not easy when you are working all alone. I have no idea how I'll get a motor back in it, but I'll cross that bridge later.

I've been banging away on the bearing races but they won't budge. Anyone out there with some experience getting XS750 steering bearings out that can give me any pointers?
 
I replaced all the bearings on my bike. I used brass drifts and a slide hammer with blind bearing attachments to get all of them out. The slide hammer is essential.
 
Finally, a litte bit of progress. Well at least some photos.
Since I got the engine out, its easy to move the frame around and mock up some lines so I slapped the forks on, no bearings in yet, and threw the weeks and tank on it. This is what I've got so far:

7406175378_9daba15771_z_d.jpg

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Both tire are the same width, 120, but the front, on the wider and smaller R1 rim dwarfs the rear, skinny looking tire. I may have to try a Kenda 130/80 18 to get the look I am after.

7406177586_36b32de3ca_z_d.jpg

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You can really see it here.
Also, the shinko tire is taller than the normal road tire that would be on the R1 and there isn't enough clearance on the fender so I'll either have to grind off the mounts on the forks or work up some slick hidden bracket to lift the fender up a little bit. I'd only need 1/4" really

I'm planning on using the original yamaha tail section in the cafe seat.
What do you think:


Long
7406179848_b9743c583f_z_d.jpg


or

Short
7406181666_2a50a902f1_z_d.jpg


I'm also planning on a smaller batter, and relocated electrics to keep the fram as open as I can. There will probably be 1" - 3/4" of an inch visible of a box holding the electrics under the seat. Otherwise, I'd like to keep the center of the frame pretty much open.

Thats all for now. I'll need to do some grinding and cutting before I get to far down the seat layout, just to make sure I have a good idea of how I can attache a the seat.
 
Looks Good....I'd say keep it a lil longer, short and stubby is cool too. It depends on how tall you are I guess
 
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