Another Yamaha SR250 (1981) cafe project

B

bartbrn

New Member
I know there's another SR250 thread here, but it hasn't had any activity for over a year, so I hope no one minds if I start another. I have a 1981 Yamaha SR250 "Exciter;" everything's there, everything works. I hope forum member "wrench85" doesn't mind me borrowing his SR250 photos (and if you do, please let me know and I'll delete them), but his 1980 SR250 is so similar to mine, and I have no pix of my SR250 put together, so here goes:

whatmybikelookslike.jpg


This was pretty much the shape mine was in when I got it (although I DO have the built-in beer-cooler carrier option), and I just now realized that these two images are not of the same bike, and I can't remember which one is "wrench 85's." Between the time I started this post, and gathered some images this morning, and now, when it's just after 6:00PM EDT, I had physical therapy and had to go to the hardware store and Dunkin' Donuts, things that always rattle my brain, and, at 64, my once-lousy memory is almost entirely kaput. NB: Just visited perthstreet and discovered that the top bike of the two pictures above belongs to a PSB forum member named "lunar_c" and posted in 2009. Hope he doesn't mind...

At any rate, my bike's gas tenk is well and truly dented, and the "Yamaha" tank lettering is long gone, (so one of the things I'll be asking about is what other Yamaha tanks fit the SR250, and what other, non-Yamaha tanks can be made to fit, with a minumum of metal fabrication), but otherwise, these two bikes above represent the state my SR250 was in before dismantling, except that my engine is considerably more spiffy than these two (not through any work of mine, I hasten to add!), my buckhorn bars are mercifully destroyed and there's currently a fairly short drag bar sitting in the clamps, and I have a complete extra SR250 engine in excellent shape, which I'll probably put up for sale here. I also have to say that, before dismantling, my SR250 ran exceptionally well, the electric starter worked a treat, and everything from frame to fork to rear shocks, and front and rear wheels and drum brakes -- both which will be kept drums -- are all in excellent condition.

I'm going to be asking a lot of questions, but here are some images I found on the net of the kind of thing I want to end up with. My thanks to "Custom Yamaha SR250 by Wesley," Moto Rivista of Spain, and Deus, all of whom do some beautiful and imaginative work. I was also thrilled to find in my searches that Yamaha made a 350cc engine (for some loony-looking balloon-tired -- and I mean BALLOON! -- off-road bike) on the same case, and that it apparently fits into the late '70s - early '80s SR250 frame with no modification -- please, anyone, correct me if I'm wrong on ANY of this stuff, because my actual SR250 knowledge is slim-to-none. When I went back to college in Savannah at the ripe old age of 40, I rode an '87 SRX250 (which solved Savannah's never-ending parking problems in a Historic District built for horses and buggies).

So here are my current inspirations, first the "Custom Yamaha SR250 by Wesley" -- whoever he is, bless his heart, because he made a VERY nice scoot out of his SR250 (BTW, those are the same drag bars I have):

Custom_Yamaha_SR250_by_Wesley.jpg


And then various creations, mostly by Deus, but the bottom bike is in Spain, from the Moto Rivista site:

Deus_Bikes.jpg


Hope I haven't bored everyone into a stupor; I'm really glad I found this forum!

Thanks

Bart Brown
 
i really like the tank on the second dues bike and the exaust system from the first with no rear fender,would look bitchin. Best of luck on you build
 
Hi Bartbrn,

Good to see another SR250 build, there are a few on here now. If you are interested you can check out mine in the tracker section. It's called Mexico. Good luck.
 
SteveG said:
Hi Bartbrn,

Good to see another SR250 build, there are a few on here now. If you are interested you can check out mine in the tracker section. It's called Mexico. Good luck.
Click to expand...

Checked out your "Mexico" build -- fantastic! I was encouraged to see many of your SR250 build inspirations are the same as mine!

http://www.dotheton.com/forum/index.php?topic=38765.msg429854#msg429854

I have a couple questions (though as I'm in the US and you're in the UK, the answers may not be specific to what I can get here, but at least I'll have some idea what to look for):

1. What brand/where did you get your new shocks:

http://www.dotheton.com/forum/index.php?action=dlattach;topic=38765.0;attach=57960;image

If anyone in the US knows of a source for these, please let me know...

2. What brand/where did you get your new seat:

http://www.dotheton.com/forum/index.php?action=dlattach;topic=38765.0;attach=57957;image

If anyone in the US knows of a source for these, please let me know...

4. The Ballistic EVO2 4 Cell 8Ah Battery Ballistic EVO2 4 cell battery you got -- was it the 100-109 or the 100-010? I'm also looking at the Antigravity Nanophosphate Lithium 4-Cell battery:

http://antigravitybatteries.com/?page_id=994

At 4.25″ x 1.25″ x 3.75″, it would be great if the Antigravity worked installed flat (and as the battery is entirely sealed and there are no liquids involved, I see no reason it shouldn't work that way -- I have an inquiry in to Antigravity, and I'll post their answer here). Laid "face down" (dead like Elvis), the battery would only be 1.25" high, so it could be mounted under the carb without compromising air-filter element space.

Speaking of air filters, what do most of you use, an oil-soaked foam element, or a dry paper element (or something else)?

Speaking of carburetors, as the stock Solex/Mikuni carb is of "constant velocity" design, like the side-draft SUs seen on so many Brit cars, has anyone done any messing around with stub stacks (aka velocity stacks, ram pipes)? Short -- around 1" to 1-1/2" deep -- well-radiused stub stacks (which will fit inside several K&N filter models, BTW) have proved to smooth airflow considerably on the SUs, generally to the betterment of torque.

Your image of the SR250 frame & fork, engine, wheels, shocks, and bars very succinctly displays what most appeals to me about the one-lunger bikes of that era: no "trying to look like a Ducati" or any other imitative nonsense, the SR250 in its fairly naked state, as seen here, is as simple and purposeful as it gets: If you had throttle, brake, and clutch controls, and a tin can fuel of fuel with a hose to the not-mounted-in-this-pic carb (and a tough-as-leather arse!), you could ride this thing, as-is, into the sunset:

http://www.dotheton.com/forum/index.php?action=dlattach;topic=38765.0;attach=57336;image

Thanks for YOUR inspiration
 
bartbrn said:
I know there's another SR250 thread here, but it hasn't had any activity for over a year, so I hope no one minds if I start another.
Click to expand...

Haha If there was only allowed to be 1 build of each model happening at once, well there would be no fourm :eek: ? Just because you start with the same platform (an sr250 in your case) doesn't mean your building the same bike ;) ! Your individualism will take care of that nicely

good luck with your build, and enjoy the journey :)
 
Hi Bartbrn,

1. The shocks are forsa and you can buy them here: http://www.ebay.co.uk/itm/180791300928?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 be aware that these are longer than the standard shocks. Shamus (who is doing a build in the specials section) also has these shocks and he is based in Toronto, so he may be able to point you in the right direction: http://www.dotheton.com/forum/index.php?topic=37624.30

2. The seat I got here: http://www.ebay.co.uk/itm/350575899041?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649. This seat is not a straight fit, and I have had to mod the frame (cut bits off) to get it to fit.

3. The battery is a 100 - 010 and I got that from the US here: http://www.ebay.co.uk/itm/310404615434?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

4. As for filters, I had planned to go with a pod (cone) and a crankcase breather. I may decide to fit a stack, but I haven't got to that stage yet. I do like the look of a stack and it may fit the bike better than a pod. I will also have to look at sourcing new jets as the bike will probably run lean.

Hope that helps. Have fun. SteveG.
 
How did this ever turn up? I'm interested to see where you went with it...
 
Hi, I'm also interested to see how you are going with it as I am currently in the process of rebuilding a SR250. I'm new to this site and am not sure if I am to start a new thread or just post on this one, but here are some picks of what I'm up to....
 

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sorry about the cheesy grin in the photo above. But it had been a while since I stripped it and felt good to get it back rolling and sit on it.
 
I think Steve's turned out so nice that we're all suffering from some confidence issues and slowing down on the builds...

DesmoBro- still goin with that funky rear fender?
 
not sure if I'm going with it ....it's still stuffed in there tho HAHA....I keep seeing 250 dirt bike swing arms on CL so now i have Mono shock on my mind
 
Damn Desmo I would like to see that. I have been away from the forums for a bit, but yeah still not finished... I have a 305cc conversion planned for mine. I really should update my thread.
 
bud. said:
How did this ever turn up? I'm interested to see where you went with it...
Click to expand...

Well, like most of my 53,278 projects, this one is lagging quite a bit, due to the square-puzzle-syndrome: you know those plastic puzzles with the movable-by-only-one-space-at-a-time squares? I have to:

1. Move all the junk out of my workroom, especially my 30+ complete guitars, 25 project guitar bodies, necks, and hardware, and 47 metric tons of books and just plain crap, so I can completely paint the room and ceiling, then:

2. Move all my work tables and power and hand tools out of the garage (my wife is agitating for her side of the two-car+ garage, so she has a place to park, as winter is coming on quickly) and to my work room, which I can't do until the work room is painted (see #1).

3. Clear out MY side of the garage so I can get at the chrome roll-around wire shelving I used in the hobby shop we owned (killed by the Bush economy, 2007), because that shelving is going into either my bedroom, replacing the narrower, but shorter black wire shelving in there, or the chrome roll-around shelving is also going into the work room.

4. Before I can do that, I have to clear the chrome roll-around wire shelving of all the debris and detritus from the hobby shop, and probably temporarily store all that stuff in the bonus room over the garage,

5. From which I have to ditch ANOTHER 40-year accumulation of books, magazines, slot car track, an Amiga 1000 computer from 1987, and various other uselessness.

6. Then I have to gather up a half-dozen cafe seats, and a like number of fuel tanks, handlebars, flyscreens and fairings, and then the bike itself and its complete spare engine, forks, shocks, battery, wheels (16" and 18" aluminum-rim wire wheels, with mechanical aluminum drums), and find a place to stage all THAT stuff while I tear the 1981 SR250 down to the frame and start from the ground up.

I will keep you all posted, and thanks for all your suggestions.

Peace

Bart Brown
 
This may sound like a dumb question, but consider the source. My SR-250 has a 34mm Mikuni CV carbureter, perhaps Mikuni model BS34. I'm going to get rid of the whole airbox assembly (unless someone thinks it's a good thing to keep -- I'd like to replace the regular lead-acid battery, and replace and relocate a LiIon battery to the space taken up by the airbox). Given that situation, would it make any sense to equip the 34mm Mikuni with a velocity stack, and enclose the velocity stack within a K&N-style filter, or is that just a waste of time and effort?

Thanks!

Bart
 
you could do that, They do make metal screens that you can put over the stacks to run them "open" and not worry about Rocks and small animals etc...
 
I don't know much about stacks at all, but it seems that slipping too full of a filter around it would defeat the purpose... and is probably your most expensive option too. I'm running uni foam on mine and love it. Instead of putting the filter straight to the carb, I connected it via the old tubing that used to go to the air box. That let it fit the frame a little better, and I'd like to think that it might streamline the flow a little too.

There are definitely up sides to keeping the stock air box too... but plenty of pod or filter options to play with too.
 
Thanks for the replies! Anyone have experience with the Li-ion motorcycle batteries like the LiFePO4? I'm keeping the SR-250 electric starter, and I'm wondering if anyone knows what size Li-ion battery would be appropriate for a 250cc one-lunger...

Thanks!

Bart

PS: I have MORE than all the parts I'll use on this project, including a good, spare Yamaha SR-250 engine, front forks, and a bunch of smaller stuff, plus several café seats & pans, front fairings, fuel tanks (metal, plastic, and fiberglass), and I'm not even sure what-all, as it's all buried in the garage.
 
I use a ballistic LiFePO4 6 cell, and it seems to do well pulling over that single. I've heard from a couple guys that are running 4 cells that they wish they had gone for a 6 cell instead. I actually asked someone at ballistic too, and they thought the 6 cell would be a good fit for a 250 single.

the stock sr250 reg/rec is said to be pretty solid, even after many years, but it's always good to check it out before strapping the new batt in there. Mine was doing great, but I'm going to do the kohler reg/rec mod anyways. LI is just too expensive to risk blowing
 
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