Yamaha SR250 - A clean standard build

Shawzie

New Member
JadusMotorcycleParts said:
Cheers! How far along are you with your build? Do you have a build thread? Yeah, I will keep you posted on the 16" front wheel thing. A better brake would be awesome actually. Pretty pricy though I think?

I was wondering if it is possible to just improve the current brake by giving it a little mechanical or hydraulic help... Like have you seen hydraulic clutch conversions? Couldn't the same principle be applied to a drum brake? So you get a better/stronger action from the lever? Or even one of these things: http://www.kickstartershop.de/en/Mechanical-clutch-booster
No I don't have a build thread going yet. I really should tho as I have been watching other builds on this site for years now without posting my own. I somehow doubt I'm the only one. I'm fairly far along at this point. Need to do a seat, fenders, tuning and that'll be pretty close to done.
I think we either live with the shitty front brake or swap it out for a better one. I doubt upgrading the stock one would be worth the money. Plus I like the look of a big drum with a small rim. I haven't looked into sizes or fit or anything yet though
 

Shawzie

New Member
Fyi, 32mm seat post clamps for bicycles fit the fork tubes. It made it really easy and clean to make headlight ears with. Cut some ally plate and hand finish with a file and it turns out pretty nice. Bicycle parts are easy to come by where I live.
 

JadusMotorcycleParts

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Shawzie said:
No I don't have a build thread going yet. I really should tho as I have been watching other builds on this site for years now without posting my own. I somehow doubt I'm the only one. I'm fairly far along at this point. Need to do a seat, fenders, tuning and that'll be pretty close to done.
I think we either live with the shitty front brake or swap it out for a better one. I doubt upgrading the stock one would be worth the money. Plus I like the look of a big drum with a small rim. I haven't looked into sizes or fit or anything yet though

Its true man, I have built a few bikes and not posted anything while at the same time have read a lot of other peoples threads and learned a lot. Its never to late to post your stuff! I got quite a few questions on that video of mine of the first SR I built so I promised myself (and them) that I would do a build thread the next time I worked on a bike. Did you ever read LunarC's build thread on Perth Street Bikes? Was a few years ago now but that was an awesome source of information and inspiration. Too bad he sold the bike to pay for his engagement ring or something! But a company bought it off him and finished it off into this: http://www.pipeburn.com/home/2011/09/17/garage-projects-yamaha-sr250-lunacy.html
 

JadusMotorcycleParts

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Yamaha SR250 - 16" front wheel conversion

I searched high and low for a rim the right size. I was hoping to buy a raw steel rim from Central Wheel and have them drill it to my hub specs. But they don't stock the 16" rims anymore in 2.15" size. I emailed a few other places and there are places that can do it, but want minimum orders of 50 and such. What I ended up doing is buying an old SR250 rear rim and stripping and powder coating it.

I also calculated the spoke lengths for this size rim but they were wrong :( Time for a reorder...
 

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Shawzie

New Member
Yes I have read that build thread. One of the better ones for sure. I was thinking of using a stock rear rim on the front. If you could share your info on the spokes that would be awesome. Very interested to see how yours goes. I'll figure out how to post pics and put a few up. I just got my garage under control and hope to get back at it
 

JadusMotorcycleParts

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Decided to turn my focus back to the seat. So I have modeled up something I think I like in 3D. I will then print it out roughly in 3D and see if it works on the bike. I am hoping to design the seat so that it fits with very little frame modifications and so I can make a production run of them - for other builders working on the SR250. I have seen many nice SRs ruined with a crappy home job seat (I am one of them - my first SR build). IMHO it is worth it to fork out a bit extra for the seat because it really does make a bike...

A quick note on seats... The first seat I made, I made ultra thin - I wanted it to be one of these brat-style slices of foam - as low profile as possible. After riding that thing for a couple of years I have decided I am over thin seats! Haha I actually have turned right off the look of them as well - hence this seat design will be a little thicker, maybe 80mm-ish.
 

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JadusMotorcycleParts

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Shawzie said:
Fyi, 32mm seat post clamps for bicycles fit the fork tubes. It made it really easy and clean to make headlight ears with. Cut some ally plate and hand finish with a file and it turns out pretty nice. Bicycle parts are easy to come by where I live.

Thanks for the tip! Never thought of that. It seems that 32mm forks are super uncommon in the motorbike world, but like you say 32mm shit must be common on bikes :)
 

JadusMotorcycleParts

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Shawzie said:
Yes I have read that build thread. One of the better ones for sure. I was thinking of using a stock rear rim on the front. If you could share your info on the spokes that would be awesome. Very interested to see how yours goes. I'll figure out how to post pics and put a few up. I just got my garage under control and hope to get back at it

Yeah man def, I'll let you know the dims/specs when I get the next order and confirm they are correct. No use sending you information that is wrong! Haha, this way I wear the cost of the development

Always good to get the garage under control!
 

Maritime

Over 10,000 Posts
cool build so far. LunarC was a member here and his build was posted here in parallel with the Perth builders site. He had some great ideas and attention to detail for sure.

Cheers
 

JadusMotorcycleParts

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Glued the printed seat pieces together but don't like it... Will make some small adjustments then print another before I start making the base and shaping the foam.

Also got me some YSS shocks from wrenchmonkees to get the frame/tank line right/level. Went up to 335mm i think? Plus the rear wheel all laced up. That was a pretty straight forward affair - take lots of photos of spoke lace pattern, disassemble, measure spokes, order a custom set in stainless from central wheel, powder coat the rim and hub, then lace it all up and have a tyre fitted! This time a 130/90 Metzler ;D
 

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JadusMotorcycleParts

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Lots of stuff arrived yesterday so got a bit done today. New front wheel spokes were mostly correct this time (will make a document to update with the correct dims) so I laced that up. Also Got some really cool stuff back from my machinist friend. The parts are aluminum and anodized in black. Includes the 2-piece fork brace plus gaiter adapters, the tank lowering kit, a center mount bracket for the speedo and and a top yoke tidy kit.
 

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stroker crazy

crazy as a fox
Nice parts!

It's a pity I live on the other side of the planet, otherwise I would ask for an introduction to your friend.

Crazy
 

cosworth

Coast to Coast
ok, i'm just gonna throw this out there but if you make some decent 3d printed bits, you have customers.
 

HollywoodMX

Coast to Coast
JadusMotorcycleParts said:
Glued the printed seat pieces together but don't like it... Will make some small adjustments then print another before I start making the base and shaping the foam.

Also got me some YSS shocks from wrenchmonkees to get the frame/tank line right/level. Went up to 335mm i think? Plus the rear wheel all laced up. That was a pretty straight forward affair - take lots of photos of spoke lace pattern, disassemble, measure spokes, order a custom set in stainless from central wheel, powder coat the rim and hub, then lace it all up and have a tyre fitted! This time a 130/90 Metzler ;D

So the 3d seat is just a moch up for the new foam seat that will eventually be??

Are there structural specs for the plastic in the printer? Just worried about the fork brace cracking..
 

JadusMotorcycleParts

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HollywoodMX said:
So the 3d seat is just a moch up for the new foam seat that will eventually be??

Are there structural specs for the plastic in the printer? Just worried about the fork brace cracking..

Yes exactly, just a mock up. If I was only planning on making one seat, I would just buy some foam and shape it - will still probably do that for this bike actually. However, I am planning on making many seats, so I want it to be right. Thats why I bother to print the full seat in 3D for fitting purposes and to see how the proportions work with the bike.

As for the other plastic prototyped parts, these are also just prototypes. I build the 3D file, print it out in plastic for a test fit, then make any modifications before I send the final 3D file to my buddy who is a cnc programmer. I help him with some modelling/design stuff and he machines shit for me. Pretty sweet relationship. I have contacts with a couple of local firms too that could do batch production runs of the parts ;D
 

JadusMotorcycleParts

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Yamaha SR250 - Shaving the front forks

Shaving the forks... without a lathe. The ghetto method: Hack off the aluminium fork mount bosses with your weapon of choice (mine was a hacksaw), grind smooth(ish) with a grinder - pref a flapper disc (be careful here not to take off too much - you cannot add material later, file back roughly with a metal file, using an old automotive panelbeating trick, paint the area you are wanting to smooth, then file lightly again - this will highlight your low spots and your high spots and give you a better idea where to file. It really helps if you have an automotive file - one with big chunky waves almost - i picked up mine for a couple of bucks from a second hand store. It keeps things pretty even. Repeat this painting and filing process as many times as you like until you feel you have shit pretty smooth. Then just sand with wetndry sand paper - i didnt go too hardout here because i wont be polishing them anyways - not a fan of shiny shit. I will probs just beadblast then paint, but maybe not even paint? Will have to see what they turn out like.
 

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JadusMotorcycleParts

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Test fit the speedo center mount bracket and top yoke tidy kit. Looks sweet! Gotta make a couple of adjustments to the 3D files and 2D drawings if I was to make a bulk order, but these were pretty close for prototypes.

Also, just finished my other bike project - a mashtard Honda XL600V. This was a scrappy as hell build with many rushed hand made parts and first attempts at many different things - welding sheet metal, welding stainless tuning downdraft carbs etc etc. Turned out a bit like a mad max bike haha ratty as fuck. I am hoping to redo everything to a much higher standard next winter. Heres hoping right?
 

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JadusMotorcycleParts

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Yamaha SR250 - 16 inch front wheel

Yus! Got the 120/90 metzler front tyre (actually a rear running in reverse) fitted yesterday and it looks dope. All chunky like.

Then I tested the fitment of the fork brace properly and fitted up a 3D printed fender. Not convinced on the size, shape or position of the fender but it is in the right direction. The fork brace came out great though - the gaiter adapters work well and the gaiters I found are the perfect size - diameter wise top and bottom and lengthwise too (hate that 'smooshed gaiters that were too long' look).
 

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