Here is my situation. My bike (1990 CBR600F) already has a Vance and Hines SS2-R slip-on installed with the factory header. I recently purchased a never used Yosimura header from ebay. This is the same header used with the old Yoshi systems made back in the day for the Hurricanes. My plan is to bolt on this header while using my SS2-R slip-on and the chrome midpipe that came with it. In order to make this system work, I need to fab up a short piece of pipe because the new header exits underneath bike while the old header exited under the right hand side of the bike. The collecter on the new header hasa 2' OD which means I can use pre-bent pieces of exhaust pipe from any parts store. The only thing that concerns me are the crimp bends in the pipe itself. BUT here's something interesting. A mild built Chevy 350 will flow 2.25' pipe without any restriction. My 598 cc engine is only 36.5 cubic inches. It would take roughly 10 cylinders from my bike to equal that of a 350. SO regardless if I decide to use these crimp bent pieces, they should still flow adequatly for my relatively stock engine. To make this work I'm only going to need 2 30 degree pieces to make the system fit together. Just eyeballing those 30 degree pieces, the diameter doesn't look to uncheanged but like I said im only flowing 37 cubic inches. What are your thoughts for a situation like this?

 

Hey try to do this with your exhaust. I was also thinking the CB 600 hornet uses a mid pipe that turns up behind the engine. I wonder if it can be used on a F3 because the engines are reported to be the same. Something to think about.

[IMG]local://upfiles/6966/EBFA05F6C8494C54A2BC36010EADE3F4.jpg[/IMG]

 

No, my bike won't support an exhaust like that because of the fender locations. Besides I like my pipe right where it is.

 

thats a kool bike I like that exhaust

 

If I still had my stock swingarm I would do this mod and use either a 600rr canister or a set of ducati pipes in place of the fender. Then I would get a fender eliminator kit for my signals and plate. Plus if you are a heavy person make sure your shock is in condition and not soft. Please post some pictures when you are finished.

 

I dont think you will have a problem with the fab work but you should try to find mandrel bent elbows instead of crimp bends, exhaust flow is tricky.

And about the flow compared to the chevy yes you are correct about the diameter of the pipe but you have to understand that your engine revs alot higher than a 350 and the higher the rpm the higher the exhaust pressure. One of the main hp gains of an after market exhaust system for cars and bikes is the mandrel bend technology because itreducesflow restriction, the less back pressure the better because ifthe exhaust gasesflow out fast enough it actually creates an energy to help the next exhaust gases to flow out easier. Which in turn increases theamount of air enteringthe motor, which produces more power. Themore disruptions in flow (i.e. crimp bends inside the exhaust) the more back pressure equals less hp gain.

Don't worry so much about the flow just try to find some clean elbows and you should be gravy.

 

Well I finished it up and I think it looks great!! All though I wasn't able to find a mandrel bender, I still think it flows better than the old header. The exhaust is definitly louder and after taking it for a short ride, I must say it was an overall improvement. I also added a 6 degree ignition advancer as well. I have pics posted in the F1 section under the thread titled "new header questions".