Yamaha SR250 - A clean standard build

[JadusMotorcycleParts]

Back to the drawing board for the brace.  Its one thing to see a sketch of it, then its another thing to print it out in 3D and 'feel' its size and proportions.  And this one was waaay to big and chunky I thought!

[JadusMotorcycleParts]

Another attempt at the fork brace - this time much thinner and more in proportion.  Plus another attempt at some above yoke clip-ons.  This time in more of a riser bar style.  I like these a lot more.

[JadusMotorcycleParts]

Designed and printed (in pieces) an exhaust headers.  I like the style of header with sharper lines and tighter curves rather than the vincent style swooping bends.  So I tried to match the angles of the frame/engine so it looked right.  Has anyone ever used an exhaust header calculator?  I tried a few but ended up liking this one the best:  http://www.mezporting.com/exhaust_length.html

I also bought and tried reading Philip H. Smiths 'Scientific Design of Exhaust and Intake Systems' but it was just too heavy for me.  Most of the principles I understood but I got caught up in all the thousands of possible variables.

[JadusMotorcycleParts]

Seeing how the design fits everything in.  Not too sure about the ignition location...

[JadusMotorcycleParts]

Thought it was about time I figured out what I will do about the seat - for me the key to success for the SR250.  The real make or break.  No better way than to sketch up some ideas and print them out and test them!  Only had time to test the fit for the base of the seat and the mechanical attachment mechanism.  I decided I don't like the new trend of 'lush' plaid, pleated or diamond pattern seats...  I will go for something cleaner - a bit like Roland Sands seat designs for the modern Triumph Bonnevilles maybe 

[Shawzie]

Good start.  I've been working on an sr250 for quite some time also. I've really wanted to do a 16 front wheel conversion. Maybe even put on a 2ls front brake from a 400. I hope to see you do it!

[JadusMotorcycleParts]

Cheers!  How far along are you with your build?  Do you have a build thread?  Yeah, I will keep you posted on the 16" front wheel thing.  A better brake would be awesome actually.  Pretty pricy though I think?

I was wondering if it is possible to just improve the current brake by giving it a little mechanical or hydraulic help...  Like have you seen hydraulic clutch conversions?  Couldn't the same principle be applied to a drum brake?  So you get a better/stronger action from the lever?  Or even one of these things:  http://www.kickstartershop.de/en/Mechanical-clutch-booster

[stroker crazy]

The black bars look waaaaay better than the first attempt.

Very useful exhaust calculations can be found at http://www.dotheton.com/forum/index.php?topic=39814.60
Scroll down to Reply#67

Crazy

[cosworth]

Have a look at my build in my sig. I'm a big fan of the SR250. If I had 6 in my yard I could build them all different and have a blast doing it. Tracker, brat, bobber, cafe, scrambler, and board tracker.

A very versatile base.

[JadusMotorcycleParts]

Thanks for the links guys.  I really like your build cosworth! Nice job.