twistekeys said:
Thanks for the advice... I honestly will work for 5 hours before I go riding for 1. I personally enjoy "motorcycles" more than riding. I refer to myself as a motorcycle enthusiast, as opposed to a motorcycle rider. I love admiring the engineering, materials, the design, the aerodynamics, etc. That they thought of at the time. It's beautiful. Riding it is a perk.
Well said man. I know I am digging up an old thread here but I really relate to you on this. I do enjoy riding, dont get me wrong, but I love being in the workshop even more. I also like reading up about technical stuff and keeping up to date with all the newest tech. I get a big kick out of it. I got into bikes from reading the biography of John Britten. Being a kiwi I was really interested in his story - he is an idol, a hero. After reading that book I got into engines in general first actually - started designing and machining my own compressed air engines. Bikes came after - as a natural progression of the simplest form of getting a fun use out of an engine ;D
Anyway, back on topic... Performance for the SR250. I looked into this a couple years ago and bought a whole lot of parts then shelved the project for lack of time and moving countries. There are two paths you can go - the cheaper, bolt on path and the expensive, very involved path. Depends what you're looking for.
The cheaper bolt on path would be some form of aftermarket header - but you would have to fabricate this, because there are not any (were not any) available on the market as an aftermarket part. There is a tonne of information out there to be able to calculate the best exhaust length and diameter for this engine - based on valve timing, bore/stroke and rpm zone. Simply changing the silencer is not gonna do much at all - its the double walled (26mm inner diameter) header that is restrictive. Then you can ditch the airbox, which in this case is restrictive. You wont be looking at crazy performance gains but it will help with flow. Even better would be a velocity stack, but that's not very practical on the street. As someone stated in a previous comment, the emgo pod filters are terrible quality, you'd be better to buy a proper k&n oiled filter or a good foam filter - think UNI filter or RAM AIR filters. These are good. Then you would have to spend a lot of time getting the jetting right otherwise its a wasted effort. There is also tonnes of information on how to do this right.
I could go on and on about the expensive route but I still wouldn't think it would be worth it for this bike. If you can get it to do 120-130k comfortable on the highway with the cheap mods (which I did) then I would call that a job well done.
For the project I shelved, I bought:
_ Warrior inlet and exhaust valves (1mm larger in diameter)
_ Webcamshaft cam regrind No 388
_ Warrior piston and sleeve
_ Warrior exhaust header to cut up and weld back together to fit the SR
_ Stronger clutch springs and fresh friction plates to cope with the (expected) power increase
_ 36mm flatslide Mikuni Carb
_ Custom copper head gasket
I would love to find the time and motivation to get it off the shelf again but that may be a ways away yet :
What did you end up doing btw?
