250cc YDS 7 Cafe Project

el_simo

Zi goggles, Zey do Nothing !!
Hi guys,

I recently bought a 1972 250cc Yamaha YDS7 for €250. Its a non-runner but is in pretty good shape. No keys etc. None of the parts are secured as the previous owner shipped it from the UK. The bike is missing a few minor parts but I'm sure they wont be too much trouble to replace. The tank is pretty rusted inside as you can see in the picture. I was hoping one of you guys may be able to give me some advice regarding this?

I graduated last year in industrial design so I'm hoping to try out a few ideas and get some practical, hands-on experience. I'm looking forward to designing, building and finally riding my very own cutom cafe! My dad, who is nearly finished restoring a 1974 Honda C 50 is ademant I restore the bike to it's original condition but the appeal of a cafe is too great. He'll be helping me out with the mechanical end of things.

I'll be posting up some concepts soon enough. For the meantime I'll be focusing my attention on the engine.

Anyways, Im looking forward to showing you guys my progress.

Si

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Looks fine here, as you can see it's basically the RD250.

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Nothing was secured, most things are just held in place with various different nuts and bolts.

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The block looks fine, may need to be blasted though I'd say.

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Lots of blue tape holding the headlight etc. together. I dont think the clocks are originals.

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The tank got a respray.

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As you can see the rust inside the tank is a bit of a problem. I was hoping to get some advice re:cleaning/blasting this here.

 
Wow!
I hear your dad too!
Simple ace bars, rearsets and expansions, nothing unreversable would navigate a safe middle ground?
:)
 
I agree with your dad, but Erskine came up with a great compromise. DS7's are getting rarer and that one is about 95% original. I'd be looking for the bits to make it stock and sock them away for the day you want to try something different, and in the meantime change the appearance. Looking forward to seeing your ideas.

Are you thinking classic racing Yamaha or something completely different? Obviously as a designer you aren't thinking chopped off fenders and checkers but are planning something original but true to the light, race looking heritage. Yes?
 
If you're looking for a bike to experiment on why not pick up something common?
The YDS is rapidly becoming a valuable antique, it's a design classic.
I suppose it depends on how you are viewing it , either as a cheap bike to play with,
or, as a complete and utter freaking Bargain!
On UK Ebay I reckon it could get 4 times that, as it is.
 
This is gonna be a good one, I'll be checkin' in.
I have a 360 for my first time.current project.
Looking to get a 2-Stroke scoot goin', right after this one.
 
Erskine said:
If you're looking for a bike to experiment on why not pick up something common?
The YDS is rapidly becoming a valuable antique, it's a design classic.
I suppose it depends on how you are viewing it , either as a cheap bike to play with,
or, as a complete and utter freaking Bargain!
On UK Ebay I reckon it could get 4 times that, as it is.

Thanks guys,

Sorry I havent posted in a while. Your comments do gimme some perspective ! Ive decided to run two concurrent projects. The restoration of the original whilst adding non-invasive cafe parts ! Ill mothball any stock/original parts I dont need for future keeping. My one problem is I wont be able to take my new angle grinder to the frame ! Oh well !
 
Updated pics,

Bike now fully stripped. I dont know what the previous owner had been doing to the bike but there was wheat in the carbs, sand in the barrels and a load of rusty looking water in the crank case ! Ill be looking to get the bearings replaced on the crank shaft as a priority. While Im waiting for possibly the only guy in Dublin with the skills to do that Ive sent the casings off for blasting....

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Bit of work to do here...

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Screw heads were in bits ! Some work getting these off

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Nice tidy little engine

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Nervy with the mallet !

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Gunk everywhere, the bearings dont sound too good atall !

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Thats as stripped as it gets I reckon

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Everything arranged and boxed. Onto the next phase, spending money :-[ !
 
Nice basis, but the next step is planning not spending. Have you worked through your ideas for the way you want it to look and have you fabricated those parts before you start to paint and cut things?

There should be a few people around that can rebuild that crank starting with the legendary Stan Stevens across the water in Kent. Find local racers who race or build old TZ/LC/RD racers. Cranks are all more or less the same. There are differences, but in terms of locating someone who can build them and source parts, the differences don't matter. Check out places like http://pjme.co.uk/acatalog/Yamaha_RD350__Engine_Parts_Botom_End.html for crank bearings and con rod kits and seals etc.

If you have CAD skills or other graphics software available that's a great place to start. Scan in a pic of the bike form each side and go to work on your design. Cut and paste parts from other bikes until a look appears that makes sense. Try to keep proportions in mind. It's a physically small, low bike and it doesn't make a lot of power so try to avoid super wide tyres etc.

And good luck I'll be interested to see what you come up with.
 
Cheers Teazer,

That site has gone below my radar so far it looks great ! Ive been on Yambits & PGMYamaha. Both seem decent too . Yeah plan today now is to finish my line drawings, these Ill scan in and use illustrator or equivilant to sketch up some concepts and colour schemes. Ive already an idea in my head but as always in design Im gonna give some other options a go too n mix it up. I dont think Im going to be massively chopping it etc. I like good, clean, no-nonsense design. If it doesnt have to be there then take it out, if it does, can it be cleaner and more simple looking. Alot of pressure now saying I did design in college ha ! Sure well see what happens !
 
Just a quick update. Ive got the casings sandblasted in a local powdercoaters. I think it was a bit of a harsh job but its the first time I got a job like this done so Im not too sure. I gave it a go sanding the casings with 280 grit to give it more of a brushed ali look. You'll see the look I'm after on the sproket hub below...

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Hub Sproket

So after trying and trying with sandpaper I gave up. Im going to talk to the powdercoater this week and discuss my options. Essentially, I want all my visible cast ali parts to have that brushed look. Ill give each of these a coating of clear satin lacquer. Heres a comparison of the desired look and what I actually have...

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Hub Sproket & Crank Casing

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Complete Blasted Casings

If it comes to it Ill ask the powdercoater to finish all the relevant parts in the same style as the inside of the casings, I think this finish is sweet. It looks clean and neat.

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Hope this is visible.

I gave my crankshaft to a mechanic in Dublin to give me his opinion. He wanted €160 for labour alone. Lucky for me, my da found a rebuilt crank on ebay. Strenghtened conrods and new bearings & seals. Won the bid for €180 I was chuffed! While I was waiting for all of this I set to work on my forks and hubs. As you can see my sproket hub is nearly there. Because this is hidden mainly behind the sproket its my practice piece, any mistakes wont be immediately visible. Once I have a technique, Ill start on the rest.

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Before & After

I took off the rear brake shoes. Original Yamaha parts and barely any wear!

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Shoes Off

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No Wear

Next was the forks. These were shot when I got it. They came apart relatively easily, I left the seals in for another days work. Im preparing for alot of cursing come that job! The lovely chrome dust covers were a bit worse for wear due to rust. Anyone know how common these are? At the moment I only saw a pair on ebay for €60 and am nearly at my budget for this month.

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Forks Apart

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Poor Dust Covers

Right lastly Ive noticed some pitting in the cylinders and recess where the crank bearings sit. I dont know how how all this got in here and not really sure if it will affect my rebuild or not. Thoughts cheers?

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Pitting in crankshaft recess

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More pitting

Right sorry bout that I said it would be a quick update. Abuse deserved!

Teazer, I do have a plan, Ill be posting up some sketches im working on soon. Just rendering them at the moment. Cheers for the continued advice man.
 
Cool DS7 project. Do yourself a favor...use the later RD250/350 7 friction plate clutch (you really only need the center hub, but it's easier to find a complete assembly used). Yamaha updated the clutch in late '73-early '74 . Even a good running 250 will make a 6-disc clutch slip, especially w/ porting and or pipes.
 
202wagon said:
Cool DS7 project. Do yourself a favor...use the later RD250/350 7 friction plate clutch (you really only need the center hub, but it's easier to find a complete assembly used). Yamaha updated the clutch in late '73-early '74 . Even a good running 250 will make a 6-disc clutch slip, especially w/ porting and or pipes.

Cool thanks man. Yeah my pops and I were discussing replacing the plates so while we were at it may as well upgrade eh? Something like this: http://www.pgmyamaha.com/mk029.html ? This is my first time doing a project like this so Im learnin as Im going. Thanks for the advice.

Si
 
That pitting isn't an issue - you can ignore it. What you do have to do is to make sure all the threads are cleaned out and the faces are completely flat. If you can find an RD350 top end it will make for a nice upgrade.

Build the forks without those chrome covers - just get new seals and dust covers from MikesXS.com or your local supplier.

RD400 Trans is another possible upgrade if you can one cheaply - 6 nicely spaced gears.
 
Excuse my ignorance Teazer but is it really that easy ? Slap on a 350 top end or throw in a 400 transmission? Id like a nice power boost alright but Im getting the cylinders rebored and new pistons at the moment +0.25. It may be an option down the line alright thanks for the suggestion ! Serious Noob here haha !

Waiting on my gaskets and seals now cant wait to get this engine rebuilt. Seems like ya cant do one thing on the bike without getting something else done too ! Money, money, money :( !
 
Got my crank casings back from powdercoaters. As Ive originally said I wanted them the same finish as the hubs (brushed ali). As you can see below they came back a little bit different. The job looked rushed and little bubbles were all over some parts. I brought them straight back and showed the head guy. He was pretty decent saying if he had have known he wouldnt have let them leave the shop. Hes going to do them again for me personally. I brought my mother's baking tray with me to show him the exact finish I wanted. Im afraid if it doesnt come out as Id hoped Ill be coating hubs and tubes to same colour. So while Im waiting Ive kept at the fork tubes. I ad hoc repaired the fork tube I damaged with metal epoxy. I gave it a number of coats into the crack and hammered it back into shape on a bar. Heres my panic help thread:

http://www.dotheton.com/forum/index.php?topic=28194.msg303909#msg303909

So Ive just been spending my time getting all my ali parts up to a nice brushed finish. In the mean time my crankshaft came. Its pretty sweet. Strenghtened con rods TZ bearings. New seals and gaskets also came.

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Powdercoated engine parts

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Some of the rushed job and bubbles

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Different to what I wanted

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Sanding the forks. Started with 80 grit then onto 240 grit. Didnt need to go any further.


Interestingly the powder guy told me that those bubbles occur with metal when its baked for powdercoating. As it was rushed the gas was not allowed to fully escape before it was finished.

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New crank shaft

Si
 
Top end:
350 RD will slide straight on. I can't remember all the stud lengths on all the different motors, but I think that combo works OK. Worst case scenartio, you need 8 slightly longer rods to go with the taller cylinder.

Transmission:
DS7 5 speed can be replaced with a complete RD350 2 speed or RD400. I'd replace teh primary drive gears at the same time, but not strictly necessary.

You could also use a TZ350 trans in there using stock RD400 selector cam and forks, but I would not recommend that on the street.

Crankcases from DS7/R5 to RD250/350 to all TZs from 72 to 80 are basically the same. There are detail differences, but all except the 400 interchange.

You could machine those cases to take TZ rubber mounts if you felt so inclined, but RD400 had larger bosses to take the insulators, so those can't be retrofitted to yours.

Basically any model trans or ignition can be made to work.

A few years ago I had several TZ motors and more than one had street bike cases and there were some odd hybrids in that pile - not all were good ideas though.
 
Much of a power increase id say !? Ill have a look around Teazer, if I come across some Ill be asking you loads of questions no doubt ha.

Thanks mate
 
The rebuild began today ! Ive been waiting ages for my new pistons to arrive n then have the cylinders re-bored. While I was waiting I got my crank casings, heads n fork legs re-powdered. Much improved than the first time ! Still prefer the raw look but I think i can work with this. Gonna get the hubs done in the same finish now.

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So started the clean out of the casings, didnt take too long, not much blast material left over.

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So it was great starting the build, began with the gearbox. All went well until I had the gear selector drum in, n it would turn, loosening it off it sounded like a bag of spanners dragging across the ground ! Fuckin roller bearing inside the casing is ruined. Took a while to knock it out, now ive to go hunt one of them down !

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Heres a question too for you guys. Got talking to some bike builder here bout this and that. In talking I mentioned to him I was getting my engine powdercoated. The guy told me cause its air cooled I should completely avoid coating the heads as the fins wont cool enough. Now I told him he was talking shite but he was adament about this. What you guys think ? I got my top ends coated already, ill be getting the heads done in flat charcoal as soon as I can.

Well hopefully I get this bearing sorted n I can kick on with this thing a bit more, the breaks are killing me, love being in that garage tinkering away with the radio blasting out tunes !
 

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Right so, I got a break to work on the bike over the Christmas. I had to wait for the powdercoater guy to finish the casings yet again (I wasnt happy with the first finish!). So I got the heads back from him...

Disaster, lots of sanding to get that off. Dont worry, the part you see is a spare, I didnt do the others in the same way, did them on a block.

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Gearbox back together, the Haynes Manual made a mistake on the placement on the selector forks so I tried n tested till it felt right.

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Rebuilt shaft in n casings were then put together.

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More pics of the casings and clutch rebuild will follow...
 
Spent most of the weekend tinkering with the oil pump, disaster !! Manual doesnt describe quite how fiddly stripping this thing is !! Also that f*&!king cog ! Took it off and spent the next hour looking for 3mm length pins under my couch ! Those that have stripped one might understand ! Ill know for next time !

Anyways, new seals, gaskets and screws onto my now clean oil pump ! :D
 

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