X2/SXR800 Exhaust Question

[Moto218]

Trying to get a few things figured out on my build, Im throwing a sxr motor in my x2. the motor came with the stock pipe, the 650 i took out has a coffman on it, should i run the coffman on the 800 or the stock sxr pipe?? Note running the motor with twin SBN44's
Thanks!

 

[jetx]

I would run it with the coffman

 

[Vumad]

You will get better performance from the 800 pipe and something like a rn superjet waterbox, but it doesnt bolt in. Its a nightmare. If you want to ride it ever, use the coffman.

 

[Moto218]

You will get better performance from the 800 pipe and something like a rn superjet waterbox, but it doesnt bolt in. Its a nightmare. If you want to ride it ever, use the coffman.

So the stock sxr pipe would just end up being restricted at the water box unless I run an SJ water box. I eventually want to run a wet pipe

 

[Vumad]

So the stock sxr pipe would just end up being restricted at the water box unless I run an SJ water box. I eventually want to run a wet pipe

I don't think there's going to be any difference between the stock pipe and the Coffman and I don't think there's going to be any issues with the stock waterbox with those pipes. I think the sj waterbox is a good upgrade when you do the ffp sxr wet pipe,

but again, it doesn't fit right without changing the tank and cutting the hull. That is why we run 650 manifolds, to fix the head pipe angle, which messes up the chamber angle, and the chamber doesn't clear the tank, and I think it's terrible to dent chambers. I didn't run a stock tank with the sj waterbox but I think it would work. I think it's better to cut the hull to clear the head pipe because the 650 manifold issues I'm dealing with sucks.

It's all options to consider. Personally I'd run the coffman and enjoy it.

 

[Vumad]

Hulls are cheap. I'd find a second hull, clearance for the head pipe, run a right sides rear exhaust, put in hull inserts for whatever tank you want so the pipe fits, use a junk motor even a 650 is fine to bolt the fpp pipe in to test clearances, do the other mods you want, then move everything over to the new hull when it's all done. The cut as you go results in never riding. I know that better than anyone.

 

[Moto218]

Alright yeah I've been tossing up the idea of having another hull for awhile I might as well do that. I'll run the coffman for now, I mocked up the sxr pipe and I had about a half inch gap to the hull. I'm guessing with the vibration of the motor it's gona hit. Thanks for all your help!
Hopefully lake test it next week then I get to figure tuning the SBN44's.. that will be fun

 

[Vumad]

Alright yeah I've been tossing up the idea of having another hull for awhile I might as well do that. I'll run the coffman for now, I mocked up the sxr pipe and I had about a half inch gap to the hull. I'm guessing with the vibration of the motor it's gona hit. Thanks for all your help!
Hopefully lake test it next week then I get to figure tuning the SBN44's.. that will be fun

Post pics of the mock up. Ive personally had a kawi 750 limited chamber and a sj limited chamber. Both fit denting the tank and 650 manifold. Im running my own waterbox but the sj box gave the best performance of anything.

 

[StandupWI]

Alright yeah I've been tossing up the idea of having another hull for awhile I might as well do that. I'll run the coffman for now, I mocked up the sxr pipe and I had about a half inch gap to the hull. I'm guessing with the vibration of the motor it's gona hit. Thanks for all your help!
Hopefully lake test it next week then I get to figure tuning the SBN44's.. that will be fun

I have two buddies that have ran the stock SX-R exhaust on their 800 transplants, both have worked really well. If memory serves me correctly they melted the tank ever so slightly for clearance.

 

[bored&stroked]

Never heard of a coffmans exhaust not being better then a stocker. A westcoast or PJS sure, but coffmans and factory are the only two regarded as worthy pipe upgrades. Besides a SXR probably wont fit, didn't fit my 650sx.

 

[Moto218]

Yeah I think the manifold bored out with the coffman will be the best, the sxr stock exhaust does fit. I have it on right now but I did have to melt the tank. I just need to find a diverter manifold now