Not another bloody SR250?

ManxKat

Older but no wiser
'fraid so.

New to DTT but no stranger to hacking about perfectly serviceable bikes so here's the latest victim for surgery.

Plan is vague at the moment but as:

i) this will be a loaner for visiting friends,
ii) my normal work rate is that of an arthritic snail, and
iii) it doesn't need to be any faster than it is

changes should be (ha!) limited to:

i) sourcing a less ridiculous seat (hello Jadus!),
ii) lowering the tank (hello Jadus again),
iii) fitting a louder pipe,
iv) fitting less ridiculous bars (actually I've already done that one),
v) knocking up some side panels that fill the gap caused by i),
vi) lowering the front end,
vii) fitting a headlight unit which contains the speedo/ idiot light etc., and
viii) trawling Yamaha parts list to see if the twin pot front caliper and fork leg fitted to the very last SR250s (mine's apparently a 1993 model) can be retrofitted.

So far I've confirmed that it's 100% operational, and most of the original 20 horse powers are still present, so there are no mechanical changes planned for the engine - yet.

If anyone knows the answer to viii) above that would be handy otherwise I'll leave you in peace for now.
 

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I had heard that the entire front end from a XV250 Virago will fit with an All Balls bearing kit.
 
Thanks for the input. XV250s are rare beasts in my neck of the woods but it's certainly another option to consider - I'm planning on running a tape measure over an SR125 and a Honda CB250RS in the near future to see what forks/ brakes might fit with minimum fuss.
 
Was just looking at the pic of your bike, specially the shape of the frame and side panel and had a thought.....Royal Enfield Crusader Sport replica!
 

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There's definitely a similarity there but, for reasons best known to Yamaha, the SR's top frame rail is actually horizontal (or pretty close to it). The side panel is that shape because it has to match the curve in the seat so, once the seat gets replaced (Lordy, it is so uncomfortable), there'll be a gap to fill between the bottom of the seat and the top edge of the side panel. Plans are afoot to fabricate new side panels (or modify the stock items) to resolve this.
 
ManxKat said:
Plans are afoot to fabricate new side panels (or modify the stock items) to resolve this.
Before you fabricate either a seat or side panels, check out what Jadus has done in a similar build here. http://www.dotheton.com/forum/index.php?topic=66505.0
 
All Balls sells a huge variety of bearing kits for all sorts of other front end conversions:
http://www.allballsracing.com/index.php/forkconversion

You should be able to find a different front end that was plentiful in your area, had a compatible front wheel and disk brake.
 
According to allballs cross reference, the bearings top and bottom are the same. Should just bolt on. Xv250 front end that is.
 
Thanks for the leads chaps, the search extends ever outwards! I've been chatting to Jadus and a seat will be winging its way to me shortly, I hope.

A rainy day has meant some garage time with the SR and the first steps have been taken - but for some reason I can't get any photos to load at the moment. As soon as that minor technical issue is resolved I will bore you rigid with lowering the forks, lowering the front mudguard, lowering the ignition barrel and modifying the battery box (among other stuff). The photos are great, really.
 

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OK, I have no idea what's going on but at least the pictures above have loaded, sort of.

So, from top to bottom, we have the ghastly stock front end which then gets lowered by 30mm by simply dropping the forks through the yokes. As I've mentioned above, plans are for an alternative front end at some stage in the future but, whatever I do go for, it will involve this level of height reduction so I thought I might as well get used to the ride. Basic physics tells me that it might actually improve the feel of the bike as the stock settings give a very vague sensation, so anything that sharpens up the steering must be a plus (it'll probably lower the C of G by a mm or two as well - bonus!).

The next "quick fix" was to drop the front mudguard (again by 30mm) to reduce the vast, and ugly, gap between it and the tyre. Judging from the radius of the mudguard it looks like it was designed for a larger front wheel but a future appointment with Mr Angle Grinder will shorten it down so that isn't so obvious. Mr Angle Grinder was out of action yesterday so there's also some excess metal to be pruned where the original mounting holes were.

Next for lowering is (will be) the ignition barrel courtesy of these high tech bits of old stainless tube (carefully cut to 25mm) which have some oil line jammed inside them to centre the bolt. The reason for this outbreak of lowering is that, with the clock binnacle gone, the ignition barrel will stick out like the proverbial sore thumb so I wanted to drop it down as far as I could behind the headlight. A coat of satin black paint is scheduled to make them blend in better with their surroundings.

The "silencer" was a find at a flea market last week. Marked up as a Matchless part it was sound if not too pretty so surely it was worth £1? On closer inspection at home the fittings turned out to be Metric and it fits the SR's down pipe perfectly. As an added bonus, it had taken a whack at some point which angled the body of the silencer upwards, just right to match the angle of the stock pipe - so all the mounting points line up. Result.

Next shot is of penny pinching at its best (well, my best anyway). I wanted to get rid of the tool box under the side panel so out comes the battery box, a saw is duly applied and a flaw in my logic appears. The resulting part has the structural rigidity of wet cardboard which is not ideal when its job is to hold the battery in place. Pausing only to round up a pair of old door stops and a brass striker plate, rigidity was restored and the battery has less room to bounce around.

Final shot is a vague mock up of the headlight giving an idea of where the new digital speedo will live. Plan is to set the idiot lights into the headlight shell just above the speedo. I'm not that fussed about idiot lights (I managed to survive without them for years) but this bike will be a loaner and some of my visitors like knowing what's going on (or they could just use their eyes .....).
 
Update time.

A big box of stuff arrived from Jake at Jadus so, making the most of a rainy day, I decamped to the garage and got stuck in.

Top photo is the starting point or how the bike looked around 9am.

First up was the tank lowering kit. You will need an angle grinder for this as there's no way you'd get the stock mounting points off with just a saw. The stickers (in the photo) gave a spot on template for drilling the new locating holes. My only problem was that the new mounts spaced the tank rubbers out just enough to make refitting the tank too much like hard work so a minute's hacking with a knife got a nice smooth fit.

Next up was the big job, the seat. Again, you'll need an angle grinder to dispose of the excess bracketry and I only concentrated on the obvious mounting points. Really cleaning up an SR250 frame is a major undertaking, there is dreadful welding and odd mounts all over the place. I may get around to a proper clean up in the future but, as this is an everyday hack at the moment, I can't afford to have it off the road for extended periods. I did add my own twist to the fitting process by drilling a couple of access holes in the rear mudguard (in the photo). You might want to consider this if you use the Jadus seat with the stock mudguard as it allows you to get at the seat's mounting screws without having to drop the mudguard.

The final part was the rear frame loop. What should have been a straight push in fit was compromised by great globs of weld on the outside the frame where the mounting bolts are supposed to fit and a very prominent seam on the inside of the frame tubes - both of which needed some time with a grinder to allow the loop to slide into place.

Oh, and although it wasn't part of the Jadus bits I took the opportunity to tuck the rear light up closer to the seat while the back end was apart.

Total time spent? About four hours, which I think is time well spent for such a dramatic change to how the bike looks. I do now need to sort the side panels out so if anyone reading this happens to have a set for the Classic model (or knows where a set can be found) please do let me know. Thanks
 

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Hey man! Just found this thread! The bike is looking great 8)

You are right about the welds on the SR frame - bloody joke really.

I am planning on making some instructions for the rear frame loop installation because its not always easy or straight forward. Glad you got yours in though.

Looking at your bike I have found new motivation to get some side covers out. It amazes me how good your bike looks with just a few parts swaps! Sadly the side cover project will not be in a time frame that would benefit you :(
 
Time for another update.

Belated thanks for the comments Jake.

As this is a daily hack, stuff gets changed only when it doesn't take long to do (or I hope it won't take long to do). I'd been accumulating 535 Virago parts for a front end swap over Summer so last weekend saw me stride manfully off to the garage telling my other half: "I may be some time". Hence, I was a little surprised to find that, just 45 minutes later, I had dismantled the old front end, bolted the new one in place and had a rolling bike again, although the electrics still needed doing (more on that later). From which you can probably guess that a 535 Virago front end is straight swap for an SR250 front end.

By that, I do mean a straight swap. The steering stem is the same diameter and length, the lock stops are in the same place, the forks are the same length - even the SR250 risers bolt straight into place. Just remember that there are two different 535 front ends, one has a single piston front brake and the other has a twin piston version. The brakes, fork legs and mudguards are not interchangeable between these models. If you felt inclined to utilise the 535's clocks then the swap would be even easier but I didn't and that's where things got a little trying.

I wanted to keep things simple so had rounded up some aftermarket headlight brackets, an ignition switch and some idiot lights. I've always liked the way late '60's Triumphs had the ignition switch mounted on the left hand headlight bracket so that was replicated and the idiot lights wired into the stock harness - probably another hour for all that.

Time to check everything works so switch on the ignition, neutral light comes up, check the indicators, idiot light comes up but smoke's now billowing out of the ignition wiring. Arse. Turn everything off, disconnect the battery and take a deep breath. Once my heart beat was back to normal some prodding and poking revealed that the wires leading to the ignition switch were, not to put too fine a point on it, crap. I've seen sturdier wires on a stereo system. So, rewiring was called for and something capable of handing a bike's volts/ amps was rigged up. This time the smoke stayed in the wires (old British bike joke) - success!

A test ride revealed the forks had a great feel to them (probably helped by being designed for a heavier bike than the SR) and the front brake actually stopped forward progress. I don't care what anyone says, the stock SR's single sided, single leading shoe front brake has no place on a bike capable of 80 mph (on a good day)!

Next on the "to do" list will be the silencer (I still haven't got around to fitting it) and then a thorough shake down over Winter before a complete strip in Spring for paint/ polishing/ new side panels and maybe a speedo. What could possibly go wrong?
 

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So, were you good last year? Did Santa deliver?

Apparently I must have been exceptionally good because the long suffering SR got a Christmas boost in the shape of a pair of prototype side panels and valve covers from Jake at Jadus.

As Jake has mentioned elsewhere, the finish isn't exactly glass smooth on the side panels (being 3D printed) but that's easily fixed with some sanding, primer and time. What will take more time to sort out will be the angle the bike sits at - the side panels fitted perfectly are exactly in line with frame rail and leading edge of the seat but, as you can see from the pictures, they don't sit anywhere near horizontal. Not sure now whether to drop the forks even more (the steering is already borderline skittish with the 19 inch front tyre) and/ or raise the back end (seat height is not exactly an issue!).
 

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Making some real progress now but, with every two steps forward, there’s one going the other way. So, if you’re planning on increasing the rear ride height on your SR250 (or just fancy a snigger at my expense), read on.
The shocks you can see are 340mm eye to eye and, coupled with a drop of 30mm to the front forks, I think they’ve got the bike sitting just about right. However:

i) First problem is that the swingarm now fouls the exhaust “box”. OK, that’s not a huge problem as most SR owners will be looking to rid themselves of that restrictive, ugly, heavy POS anyway. I decided to keep the stock downpipe (but welded up the inner and outer pipes where I’d cut off the silencer to stop the inner rattling around and destroying itself) and bolted that up to a cheapo silencer (which looks a bit like the stock item) and an angled joint (aftermarket part for modern Bonnevilles apparently). Job done? Not quite.

ii) Without the silencer, the centrestand will be flapping about (and with the increase in shock length, both wheels would be touching the ground when you tried to use it anyway) so that’s another candidate for the scrap pile. We’re not done yet though.

iii) Attempts to use the rear brake lever will result in a very stiff action and a nasty grinding noise. That’s because the rear of the lever is fouling the swingarm and will need some delicate reprofiling to get things back to operational. While you’re grovelling about under the bike you’ll probably also notice the swingarm is bashing the brake lever’s return spring mounting. As I didn’t have access to welding gear, I went old school and shaped/ bent a suitable bolt, drilled/ tapped a hole in the bottom of the rear footrest loop and bolted it all up. So far, it’s stayed put but a dab of weld might be needed if it does start moving.

Other (non-visible) progress was to throw out my earlier efforts at fixing the battery box and use some scrap stainless sheet to make a more solid version which, more importantly, completely hides the battery and sundry electrics behind the new side panel. Oh, and I've started hacking a spare top yoke about to lose the stock Virago "wings".

Next step? It’s definitely going to need a proper speedo for the “stock” look I’m after and I’m hoping to be able to mock up some full length headlight brackets (i.e. that run from the top to bottom yokes) to give it the proper ‘70’s Yamaha image. Then ride it for a while to check it all works, then rip it all apart for a final polish/ paint/ clean. Then get it all filthy dirty again.
 

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I put a set of Progressive Suspension shocks on mine that were originally for a '83 XS650 Special for both longer travel and greater load; around 13" (330mm) and the rear tire just barely lifts off with the center stand. I will triple-check but did not notice any swingarm interference. Did not change the front suspension at all yet (might go to stiffer springs) as I did not want to change the rake. I'll probably create my own side panels to fit the tracker-style seat I'm going with.

RE: headlight mounts - I know you're thinking of a "full length" mount between the triples, but your new geometry may still make that headlight location look kind of high. Can you move the current clamp-on mounts lower against the triple? Or even below the triple (but not interfering with the fork), or a mount fastened to the center of the lower triple? Might make the headlight even with the tank.
 
Dammit! You're absolutely right, the headlight sits way too high. I'll try dropping the mounts but I have a nasty feeling that I might need to investigate a bottom mounted headlight so that it will sit against the bottom yoke - which of course means also finding new homes for the indicators and ignition switch. What was I saying about steps going the wrong way.....
 
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