i have my motor mounts all welded up swingarm shaveddown and all i need now is to fit the exuast/weld it. i have seen a couple of theads about the build but does anyone know from experience how to cut it or do i need a different pipe ? please help me i am stuck like a duck.....
96 cr250 in a blaster frame; making the exaust fit ???
- Thread starter hondablast
- Start date
If it were me and I went the 250 route, I would try to make a trx250r pipe fit. Other than that, cutting and welding is what needs to be done
You have encountered the hardest part of an engine swap 
fitting a pipe :-/
My idea if I ever did this type of hybrid would be to make a paper mache' copy, and practice with that. Paper mache' is newspaper soaked in a mix of flour/water paste, wraped around pipe, allowed to dry, split it and pull it off.
Highly suggest that if you have to add a bend that you make a "pie cut", cut halfway on outside of bend and cut a wedge or "pie" shaped piece from inside, adding the "pie" wedge to the outside. Avoid the temptation of cutting a wedge out and chucking it as this type of bend will upset the flow
Adding or subtracting length will move speed of powerband. One inch will move it about 1000 rpm.
Hope this helps.
Everyone love pics I:I (hint)
fitting a pipe :-/My idea if I ever did this type of hybrid would be to make a paper mache' copy, and practice with that. Paper mache' is newspaper soaked in a mix of flour/water paste, wraped around pipe, allowed to dry, split it and pull it off.
Highly suggest that if you have to add a bend that you make a "pie cut", cut halfway on outside of bend and cut a wedge or "pie" shaped piece from inside, adding the "pie" wedge to the outside. Avoid the temptation of cutting a wedge out and chucking it as this type of bend will upset the flow
Adding or subtracting length will move speed of powerband. One inch will move it about 1000 rpm.
Hope this helps.
Everyone love pics I:I (hint)
The idea of placing the pie slice in the opposite side is to help keep the volumetric dimensions similar.
Removing a slice will destroy the kinetic properties and can upset the working of the pipe drastically.
Removing a slice will destroy the kinetic properties and can upset the working of the pipe drastically.
thanks in advance guys** still looking for someone who has acually done this themselvs, i love the paper mache idea is all goes wrong i may just halfto do this
Guess I "forgot" that important bit of information. The paper pipe is only for fitment practice. I can see where a TRX 250 pipe might be a good option as it's two piece with a simple U-bend, tho don't know if it goes to far forward before the bend to work well on a Blaster.
I would do anything before cutting the frame tho.
A stub pipe/flange off the motor might be a good option for fitment, as well as making it two piece pipe.
Go to mod and swap sub-forum and do google search for cr 250 for more ideas.
also search member Best, he swaped a KTM 300 and made his pipe two piece.
Thinking about the frame, consider gusseting it now, rather than after it breaks. Two tubes in front of motor @ bottom main tubes and lower tubes right behind rear lower a-arm mounts. (search frame gusset). Also be sure to add mount off cyl head.
I would do anything before cutting the frame tho.
A stub pipe/flange off the motor might be a good option for fitment, as well as making it two piece pipe.
Go to mod and swap sub-forum and do google search for cr 250 for more ideas.
also search member Best, he swaped a KTM 300 and made his pipe two piece.
Thinking about the frame, consider gusseting it now, rather than after it breaks. Two tubes in front of motor @ bottom main tubes and lower tubes right behind rear lower a-arm mounts. (search frame gusset). Also be sure to add mount off cyl head.
Some picts that might help. I added wedges to lower the powerband a bit.Like the guy said, 1" = 1000rpm lower, about the most you'd ever want to drop the powerband.
Steve
Steve
Several wedge type bends within the area that you can get by with just one would be better. Time spent here will not disappoint. Don't hack it, whatever you do.
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