Yamaha SR250 - A clean standard build

JadusMotorcycleParts

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Just got the best mail ever! The rest of the photos from David ;D The workshop floor ended up being such a nice background and contrast to the cleanness of the bike.

I have also been speaking with Taylor from Bike Bound and it is looking like they will run a feature on it over there which is awesome! I formed a pretty good relationship with him through an article I wrote for them - dunno if anyone saw that? Here it is if you're curious, it was published back in March: http://www.bikebound.com/2017/03/30/best-yamaha-sr250-customs/
 

JadusMotorcycleParts

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But you lot get the scoop of coarse! So without further ado...
 

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ManxKat

Older but no wiser
A symphony of monochromatic loveliness! Now get it out there and get some miles on those tyres!
 

JadusMotorcycleParts

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zap2504 said:
EXIF Bike worthy!
Sadly not! Submitted, no response, followed up, no response Outcome = bike not up to standard! Or photos, or both. The standard seems to be forever shifting and the bar rising constantly. Which is a good thing I think! There is probably a lot of other factors too - timing, what is in right now, originality etc etc.

Anyway, thanks for the other compliments. Definitely a labour of love ;)
 

doc_rot

Oh the usual... I bowl, I drive around...
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Eh, they could be saving it for a rainy day. I have submitted work to websites before and it has literally taken over a year for some of them to use it when things got slow. While I personally really like your bike, websites like Bikeexif want a love/hate reaction from their viewers. Some of their most viewed posts are the ones that people hate because they can't stop talking about how much they hate it. If you want to make a splash do something totally outlandish and they will pick it up no matter how nonfunctional it is.
 

JadusMotorcycleParts

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Taxed, insured, road legal. Sigh of relief :D This is what it ended up looking like with all the legal junk on it ;D Not too bad I guess, but I will take the ugly plastic chain guard off again and probably design my own mirror mounts for a sleeker look. You can see the added license plate led bolts as well. I may as well leave them because they don't detract from the design too much. BUT, I will definitely remove the big, heavy exhaust silencer. Not only is it heavy and cumbersome, it messed up my jetting (of coarse) and quietened the exhaust note to a polite cough. Yuck.

You might also notice I flipped the mount for the horn up front - I needed the clearance for the forks to be able to compress without the fork brace hitting it. Duh.
 

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ManxKat

Older but no wiser
Good to hear the legal folks were satisfied!
Is there any way you could move the licence plate/ light assembly further up the rear mudguard or is it one of those legal requirements that it has to overhang the rear tyre?
Re the horn (assuming you're keeping it), I bent the bracket on my bike so that the horn sits flush under the bottom yoke - just gets it out of sight.
Still one sharp looking 250!
 

JadusMotorcycleParts

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Thanks lads!

After putting 1000km's on the bike I figured it would be a good time for a bit of a ride report, then I'll put this thread to sleep, call it complete and start the next project ;D

A couple things proved a little more hassle than I thought - one being the exhaust silencer and the other being the carb - which ended up being partly related, partly not.

Turns out (most logically actually) that the silence makes a big difference to the carb settings. No matter what I tried with the old Britt style silencer, I couldn't get it to perform or sound the way I wanted it to. It always sounded hollow, tinny and empty-ish. Especially because I had a reference point from the Jadus test mules (an awesome sound). Plus the carb just didn't like it. I tried two different sound/db killer inserts and even tried the perforated style with the packing, but the design of the silencer does not allow this very easily so it was a compromised solution. The bike would splutter from dot to 1/4 throttle then would go pretty ok after that. I also tried with a shorty hot dog silencer as well but that was a little too loud for me.

I ended up going with the tried and tested 17'' Emgo reverse cone silencer - the one I had used for all the dyno testing. It is not standard though, I gut out the spark arrestor plate (or what ever the perforated plate in the middle of the thing is) and re-pack it with some high quality packing material - really getting as much on as I can and as dense as I can - then tie it all on with thin wire. This set up just barely fits back in the cone but it makes the sound really deep and throaty and gutting the plate out of it means it is a very free flowing silencer. Once I installed this, the jetting settings were spot on and she pulled crisp and clean all the way to the top again.

Then a week or so after sorting that out I started having further carb problems - or what I suspected were carb problems - could have been spark/ignition but I doubted that. I swapped the carb for one tuned one I had from the other bike and the problem disappeared. When inspecting the original carb I noticed the needle was not sitting 100% in it's correct resting position (in the slide housing) and that had caused some very minute wear on it - right at the position I felt issues in the rpm range and just enough to mess things up. So I swapped it for a new OEM needle and this fixed the problem.

I also swapped the non-vacuum petcock back to a stock one. I hated the fact that you could run the risk of overfilling the carb at rest if the float needle didn't seat 100%. This happened once and that was enough for me to want to get rid of it.

The ride itself is pretty good. I ride it much more aggressively than I have with any other SR. I have been managing to scrape the pegs and have actually wear marks on the entire tread of the tyres - no chicken strips! ;D The new geometry, with ride height and head stem angle etc seems real stable - have had it up to 130k on the highway with no stability problems. I ride with a buddy of mine who has a DR650. He eats me at all the stops and straights, but I get it all back in the twisties if we are on some country roads 8)

The one thing that annoys me a lot though is how soft and unresponsive the front suspension is. I think the forks are long over due for a service. I will start there - clean them out, put in some new thicker weight oil and also add some preload spacers. If that is not satisfactory I can try the Minton mods or some emulators. Sometimes on the highway at certain speeds the forks can start bouncing/bobbing around. I think this is in part to the extra rotational mass of the fatter front rim and tyre that the stock forks are not designed to deal with - it must be some kind of frequency thing. But it could also just be that fact that they are old and tired as mentioned and need some more preload and thicker oil.

Also, anyone wondering about the brakes? I think they pull things up just fine! But then again the bike weights probably around 115kg and I'm around 70, so rolling mass is not enormous. I also have the disc brake set up from the SR250 Classic to compare to and although that is better, the drum is not as awful as people make it out to be.

Well thats it folks! Looking forward to some more riding when the Swedish summer decides to deliver... ::)
 

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zap2504

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JadusMotorcycleParts

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Thanks for the links Zap. Cool stuff. I had actually been thinking of a roller bearing conversion for the swing arm for the next project. But maybe even replacing the plastic bushes of the stock SR with bronze ones and welding in a grease nipple like I have seen people do on XS650's. I'll cross that bridge when I come to it but it's nice to know there are options and that other people have done it.
 

irk miller

You've been mostly-dead all day.
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No need for needle bearings in a swing arm. Bronze bushings are an upgrade in this situation and needle bearings are for high rotational/high rpm loads. You can also consider Oilite bushings.
 

zap2504

Member
irk miller said:
No need for needle bearings in a swing arm. Bronze bushings are an upgrade in this situation and needle bearings are for high rotational/high rpm loads. You can also consider Oilite bushings.
All true. But needle bearings are still better (if they cost the same). And (regardless if needle/bronze/Oilite) it would be real convenient to get if the proper sizes were readily available as a set.
 

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