Yamaha SR250 - A clean standard build

I fear I have made a big mistake! haha, no, just over-committed myself again perhaps.

I decided it would be beneficial to buy a bone stock SR250 to do some testing on - for the cooling and performance parts. I thought it might speed up the process and provide a blank canvas for making some installation instructions and perhaps even some installation videos. Because these bikes are not very popular in Sweden, I decided to look in Denmark as well. I found a pretty cheap bike and decided to go through all the process of importing it to Sweden. Nightmare ensues... More to come.

Dude, awesome build. I'm gonna turn my 81' SR250 into a tracker, cant wait. How are those seats/frame loops coming along? I might be interested in buying one of each if you still wind up selling them. Right now I've got the whole rear end off my bike, gonna do a bit of touch up on the frame and paint the swingarm. I will eventually wind up having the frame and all the stuff powder coated but my budget is a bit tight right now.

Thanks man!

Well I have approved the samples and ordered the frame loops, they'll be arriving hopefully at the end of June. As for the seats, on Wednesday this week I received 200 foam components and 50 base components - the metal parts I already have. So most of the parts are here! I have ordered the special vinyl and thread and that should be here early next week. Then I'll be taking a few to a local artisan to cover them.

I will also be offering these seats for sale as a 'blank canvass'. That is, the foam, the base and the metal mounting components as an assembly. Then you could either try cover it yourself, take it to a local upholster and get whatever finish you like (thousands of stitch colour, type, vinyl or leather colour/type/finish), or even trim the foam part a bit yourself and achieve an even lower profile 'bratstyle' seat if you like

As I have said previously, I've taken on a lot more design consulting work recently to bring in some money, so things are progressing a little slower with this build than they were

I did however make some time to do a proper service on this ratty SR that I bought and got it running real smooth so that's a plus. I ran a compression check and got this... Translates to around 140psi right? Not bad I thought for a 30+ year old beater bike!

I am thinking to keep this thread on track, I will create another thread for the testing of the parts on this particular bike - then it will just be easier to reference one thread for stats and performance info on the SR250. Thoughts?

That's great man. I've got my new bars, and I love them even with the stock seat haha. Money is tight right now, so I believe I'm gonna keep the stock seat for now until I can buy either one from you, or an SR400/500 seat from Motolanna. I've got all my electric stuff tucked away under the seat, so that's looking good. All I need to order right now is a battery, air filter and crankcase breather. How is you bike running with that K&N filter? Did you have to rejet the bike?

Good job man.

I haven't run the bike yet actually. But general rule of thumb is if you change anything with the intake or exhaust, you'll need to rejet, or at least adjust the carb. You might be able to screw in the air screw till it bottoms out, them back it off 1/2 a turn or a full turn. If that still runs too lean on idle and 1/4 throttle, you want to go up on the pilot. You'll probably want to go up on the main too just to be safe, but do lots of testing and plug inspections. You might want to raise the needle a notch too for the midrange.

A word of caution on the Motolana seats... They look great and the quality is also really good, but easy to install? Far from it I believe. I had a mate install one and ended up having to bend it to get it to fit - not the coolest thing to do to a brand new seat!

Yeah I agree, I've read some builds where guys put them on SR250's, and there is a lot of work involved to get it to fit.

I'm debating whether I want to go small battery like an Anti Gravity, or keep my regular sized one. If it came just down to looks, Anti Gravity all the way. But I ride in the cold a lot, and I'm thinking it might be to much on a small battery.

What do you think about this filter? https://www.mikesxs.net/parts/yamaha-xs650-54mm-tapered-oval-pod-air-filter-2-1-8

"Premium quality 54mm. motorcycle Pod Air Filter - Tapered Oval style with Chrome end cap.
(2.75") deep x 74 mm. (2.91") wide x 85 mm. (3 3/8") high (at base).

Pod is an improved replica (Dyno & flow bench developed) of the most popular brand on the market.
Features molded in internal stack, no step rubber mount flange and Chrome end cap.
Filter is supplied dry but washable filtration material may be oiled for improved dust filtration.
The flange does not block the openings in the stock carbs as other standard pod filters do.
Yamaha, Suzuki, Kawasaki, Honda.
Fits: 1980-84 stock Mikuni BS34 CV Carbs + some Mikuni TM aftermarket carbs.
Fits: Flatslide PWK 32mm. XS Performance Carb Set for XS650
Note: Each kit requires 2 filters.
Compatible with XS400Pod fits to velocity stack on Dellorto PHF36 carbs and SR250's"

My motolanna install was a nightmare to get right. My take on my build is that I bout the tank around the seat that I bough. It worked out sure, but if I were interested in still working on my SR, I'd make a metal tail from a modded tank that is the same tank as I chose. A Suzuki GT380 tank. With a simple hoop and some upholstery etc.

My current setup detracts from the overall look of the bike imho. I would not go motolanna except for an XV920 build.

cosworth said:

My motolanna install was a nightmare to get right. My take on my build is that I bout the tank around the seat that I bough. It worked out sure, but if I were interested in still working on my SR, I'd make a metal tail from a modded tank that is the same tank as I chose. A Suzuki GT380 tank. With a simple hoop and some upholstery etc.

My current setup detracts from the overall look of the bike imho. I would not go motolanna except for an XV920 build.

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Yeah thats what I have heard/seen from others as well. I have seen many build threads or build blogs with the seat being the bane of the build for most.

In contrast, these are almost a direct bolt on fit ;D

With this 'blank canvas' option the possibilities are endless Will be adding these to the webshop over the weekend.

Extreme_250 said:

Yeah I agree, I've read some builds where guys put them on SR250's, and there is a lot of work involved to get it to fit.

I'm debating whether I want to go small battery like an Anti Gravity, or keep my regular sized one. If it came just down to looks, Anti Gravity all the way. But I ride in the cold a lot, and I'm thinking it might be to much on a small battery.

What do you think about this filter? https://www.mikesxs.net/parts/yamaha-xs650-54mm-tapered-oval-pod-air-filter-2-1-8

Click to expand...

I've had anti gravity batteries in a couple of bikes and they're awesome. Let it discharge too much by mistake though and its toast. Would be the same with other lithium ion ones too.

That filter will be fine man. Not as good for filtration as a foam one but if you like the look of it, go for it

Price for one of those? and what are the dimensions looks like a modifiable pan ABS can be remolded some and welded to I'm thinking XL350 application and my HoZuki of course 2 fer deals?

I have the smallest 4 cell on my 250. I made a little pan under the seat. Cranks over just fine. My first antigravity failed and bulged but because I live in Canada, a warranty return cost more than buying a new one.

They prorate the warranty for how old the battery is. After six months it shouldn't bulge and fail. New one is a year old and happy.

This is now my antigravity sits.

Those seats look fantastic!

Tune-A-Fish said:

Price for one of those? and what are the dimensions looks like a modifiable pan ABS can be remolded some and welded to I'm thinking XL350 application and my HoZuki of course 2 fer deals?

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Just added to the webshop!

http://www.jadusmotorcycleparts.com/#!product-page/c826/1d9c3a07-3629-cb09-77a8-e33182504137

Rather than rambling off some dimensions I figure you may as well see the drawing I have for it. Dont think anyone on the intraweb could do anything with it anyway - ie rip it off. The dimensions are in gold indicating a conflict in the file but they are as they are on the parts

Because of the weird/unique bend in the SR frame I am not sure just how suitable it would be for other frames... You will know that much better than me!

cosworth said:

This is now my antigravity sits.

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Now that is discrete! I was thin king of developing another part for the SR250 and that would be an electrics tray for under the seat. Even though it is not to my personal taste, I understand the appeal of an open triangle and I have had a few people email me asking about some kind of battery box/electrics tray.

Btw, how many 'cranks' i guess do you get out of that size battery before it runs low? If you're having starting problems while carburetor/jetting testing for example? I have the next size up anti gravity on my 600cc transalp and its grunty as hell! But that one is tiny!

If I let the carb get dirty or let it sit with ethanol gas in it, it starts a bit fussy. I have run the battery down before messing with a hard start issue. Hence the kick start.

I'd say it would run for a good two minutes on the starter.

I had a minor charging issue and swapped out rectifier/regulator once. It immediately improved the cranking. It wasn't charging all that well.

cosworth said:

If I let the carb get dirty or let it sit with ethanol gas in it, it starts a bit fussy. I have run the battery down before messing with a hard start issue. Hence the kick start.

I'd say it would run for a good two minutes on the starter.

I had a minor charging issue and swapped out rectifier/regulator once. It immediately improved the cranking. It wasn't charging all that well.

Click to expand...

Cheers for the info. If I design a tray kit I will use that battery as the basis for dimensions. The nice thing with these bikes is you can always bump start them pretty easy too!

Anyone have any experience with the Ballistic battery equivalent of the AntiGravity in this size? Would be good to know for sizing/packaging requirements as well

New separate testing thread up! ;D

http://www.dotheton.com/forum/index.php?topic=70174.0