Yamaha SR250 - A clean standard build

The rear was the hardest part of my build. I had to mate a pre purchased seat to the rear of the bike. I think it's easier to do the rear the way you want and make a seat to match. That path is best for scramblers and trackers, harder to follow on a cafe build though with lines being critical.
 
zap2504 said:
Right, but what I'm proposing is only a slight change to your original design - just slightly narrower at the tank (will not affect comfort as you will be sitting further back), and slightly wider at the shock mounts (just enough to match the frame). The padded tank overlap you have designed at the front will take care of the tank rear/seat front issue. The side panels may be a different story. Maybe more of a curved slope at the top/front edge so as to better match the frame coupled with either a higher bottom line or a stepped design so that the panel is the same overall height but has more of a visual "thinness".

Right, gotcha. Will give it a shot in my model and see what it looks like. Cheers.

Also kinda get what you mean with the side covers too. You are right, the area where the frame seems to 'bulge' out at the front is kinda hard to follow so some kind of step maybe...

Interesting to hear what cosworth is saying too - that the rear end of the SR is pretty much the hardest thing to get right because its so whacky from the beginning to fit that stupid king and queen style seat! I think if I build an SR for myself after this one, I will def just cut it up and weld in some nicer frame rails ;)

I would really like to design a seat that a home builder could install easily though - without a welder etc. Hence the sort of 'work-a-rounds'.
 
JadusMotorcycleParts said:
Right, gotcha. Will give it a shot in my model and see what it looks like. Cheers.

Also kinda get what you mean with the side covers too. You are right, the area where the frame seems to 'bulge' out at the front is kinda hard to follow so some kind of step maybe...

Interesting to hear what cosworth is saying too - that the rear end of the SR is pretty much the hardest thing to get right because its so whacky from the beginning to fit that stupid king and queen style seat! I think if I build an SR for myself after this one, I will def just cut it up and weld in some nicer frame rails ;)

I would really like to design a seat that a home builder could install easily though - without a welder etc. Hence the sort of 'work-a-rounds'.
Actually I'm proposing more of a curve at the front/top of the side panels and a horizontal step part-way down (or a narrower panel) so that the top/side edges of the panel meet the frame rails better and it has less visual weight. Kind of like the OEM panels from the RD350 or 550/650 Secas. Your present design reminds me more of the OEM Kawasaki KZ400 panels.

You designing parts that fit an un-modified bike that others can use - more power to you! This is what I think is the beauty of your project!
 
This one was still my favorite sr250 seat shape
yamaha-sr250-cafe-racer-3.jpg


little taller
 
zap2504 said:
Actually I'm proposing more of a curve at the front/top of the side panels and a horizontal step part-way down (or a narrower panel) so that the top/side edges of the panel meet the frame rails better and it has less visual weight. Kind of like the OEM panels from the RD350 or 550/650 Secas. Your present design reminds me more of the OEM Kawasaki KZ400 panels.

You designing parts that fit an un-modified bike that others can use - more power to you! This is what I think is the beauty of your project!

Thanks! And I really appreciate the input. I googled all of the model bikes you mention and you were spot on! Haha. I modelled up another couple of concepts, another one like you say the KZ400 panels are, but fitting the frame better and having a slightly better shape. The other one I played around with the other style of cover - with a nice form at the top and sort of a flat part at the bottom. It still needs a little work but it is interesting to see the visual impact of the different styles...
 

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I like your style, a 3D printer is a powerful tool in the right hands and ace for trying out design-ideas on your bikes, keep it up 8)
Though I'd say mind the lines of the tank, unless you plan to change it; your seat and sidecovers follow and compliment the angular lines of the engine and frame beautifully, but mind the tank and its rounded shape or it might look out of place in the end.
 
Thanks Ferous, yeah it has been invaluable to have the 3D printer. I have used it for a lot of other projects too but it has been most helpful for this one. It really speeds up the development process and helps make decisions faster and safer - before they are made in metal :)

I recommend watching that documentary 'Print the Legend' about the 3D printing boom. Was really good entertainment.

I see what you mean about the tank. Ideally, I would make a tank for it too, which I have done in the past but my skills are just not quite at that level yet. I think it would look cool with more of a dirt track style tank - the angular style rather than the teardrop style. One of my all time favourite tanks/tank shapes is the Kenny Roberts TZ750 tank. It has been on many other bikes too of course but it looks best on that bike I think. I think it would also look half decent on the SR ;)
 

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On Friday I finally found a local contact that could make the above top yoke riser clip ons for me. A prototype at least anyway. I found some really good Swedish workshops to work with that could make a production run for a decent price, but their hourly charge rate for prototypes was insane. So this guy (who builds race cars for a living!) Will help me with the first set instead for a decent price. His workshop was so sweet - all types of welders, big lathes, milling machines, tube bending etc etc. Some day right?

I also printed out a second attempt at the side covers with some of zaps input. At least the idea of making less of a visual impact and not having them hang so low. I really like the look of these ones. As long as everything behind them is painted black, the should look pretty close to some carefully considered 'stock' ones. But they are much tighter to the frame than any stock ones I have seen.

Plus a last small modification to the exhaust for a better fitment and line to match the tank/seat line before taking orders :)
 

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JadusMotorcycleParts said:
I see what you mean about the tank. Ideally, I would make a tank for it too, which I have done in the past but my skills are just not quite at that level yet. I think it would look cool with more of a dirt track style tank - the angular style rather than the teardrop style. One of my all time favourite tanks/tank shapes is the Kenny Roberts TZ750 tank. It has been on many other bikes too of course but it looks best on that bike I think. I think it would also look half decent on the SR ;)
That's the beauty of your proposed tank mount adapter thingy - you could adapt a variety of tanks as long as the tunnel clearance was good.

RE: your header - I believe your previous one was longer, going past the peg and further underneath the brake pedal. I think longer is better (maybe even a little longer than that so that it completely clears the frame junction) - less interference with clamps if you want a silencer, and it is easier to make it shorter than longer if someone wanted it ;D.
 
Were in Sweden are you located? I'm currently living in Nybro but I'm going to move back to Lund in a year after I'm done with my bachelor in product design. Would be nice to know what workshops you been in contact with for future projects. Is it solidworks you are working in?


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JadusMotorcycleParts said:
On Friday I finally found a local contact that could make the above top yoke riser clip ons for me. A prototype at least anyway. I found some really good Swedish workshops to work with that could make a production run for a decent price, but their hourly charge rate for prototypes was insane. So this guy (who builds race cars for a living!) Will help me with the first set instead for a decent price. His workshop was so sweet - all types of welders, big lathes, milling machines, tube bending etc etc. Some day right?

I also printed out a second attempt at the side covers with some of zaps input. At least the idea of making less of a visual impact and not having them hang so low. I really like the look of these ones. As long as everything behind them is painted black, the should look pretty close to some carefully considered 'stock' ones. But they are much tighter to the frame than any stock ones I have seen.

Plus a last small modification to the exhaust for a better fitment and line to match the tank/seat line before taking orders :)


Side covers are getting there. For the exhaust, it would probably look better tucked in much tighter in front of the motor and below it. You could also sweep it back at a sharper angle to look more racey. Somewhat like an old school swept nack pipe but keeping it below the motor. Or go with a classic TT look under the centerline of the motor.
 
zap2504 said:
That's the beauty of your proposed tank mount adapter thingy - you could adapt a variety of tanks as long as the tunnel clearance was good.

RE: your header - I believe your previous one was longer, going past the peg and further underneath the brake pedal. I think longer is better (maybe even a little longer than that so that it completely clears the frame junction) - less interference with clamps if you want a silencer, and it is easier to make it shorter than longer if someone wanted it ;D.

Yeah, was hoping that kit would make it a bit easier for people to get different lines with the tank on their bikes, plus trying other tanks.

Re the exhaust, yeah, I wanna make sure the clamp position to the header and silencer is not gonna hit the brake pedal or frame.
 
Eleganten said:
Were in Sweden are you located? I'm currently living in Nybro but I'm going to move back to Lund in a year after I'm done with my bachelor in product design. Would be nice to know what workshops you been in contact with for future projects. Is it solidworks you are working in?


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Im living in Malmö and my workshop is in Arlöv. Yeah man, get in touch when you come down. Yep, solidworks :)
 
Though I recognized the background in the picture. Is it your own workshop or do you rent a space? I had a hard time to fined someplace to harbor my bike when I lived in Lund. Nowadays I can keep it in the school workshop


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I rent a big space - its actually a converted laundry basement. Yeah, I had a really hard time finding a space too - especially in Malmö. Thats why I ended up in Arlöv haha. Nice you have a place now. Is your bike functional? It would be cool to meet up for a ride sometime :)
 
teazer said:
Side covers are getting there. For the exhaust, it would probably look better tucked in much tighter in front of the motor and below it. You could also sweep it back at a sharper angle to look more racey. Somewhat like an old school swept nack pipe but keeping it below the motor. Or go with a classic TT look under the centerline of the motor.

Thanks Teazer. I considered quite a few exhaust designs, but I decided I liked the pipe following the frame downtube line and having 2 simple bends - nice, clean and simple. I do like other designs - attached, but for this build it should be simple. This pipe is a low slung pipe and in the future I plan on designing and selling a high slung pipe like was sold with the XT250 (rambo bike ;D) and the XT500s of course.

I def agree with you about keeping the pipe closer to the motor - after this prototype I have modified it so it is a whole 30mm tighter to the bottom of the motor and it looks a lot better :)
 

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Heres some ideas of where i took influence from... I really like the angles of these pipes over the stock ones (first image). In the other 2 images you can see the pipe is much more angular, simpler and matches the frame downtube.
 

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