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Mickey Dunlap
05-17-2015, 12:32 PM
Well I was getting ready to pull my motor to install the 350cc big bore kit so I could degree the new cams in to make sure everything is good and get it back up to the dyno, but then I seen how small the pipe was inside the first inch of the pipe. It necks down to a 1 inch pipe inside, it looks big enough on the out side but it's a double wall pipe. I would have liked to used 1 3/8th O.D. pipe that the aftermarket pipes would be, but I only have 1 1/2 O.D. so I built it with that the first part, then jump it up to 1 5/8th into a little bigger back to a Muzzys muffler I had sitting around. We ran 1 1/2 pipes on the 200x for years so I think it will be OK.

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Jmoozy27
05-17-2015, 01:26 PM
That muzzy looks nice, it should make a nice thump... Did you do anything special with the intake?
userj8670
05-17-2015, 04:48 PM
That looks sweet Mickey!
big specht
05-17-2015, 05:03 PM
Now that would be a dyno test to do. Before and after on just the pipe
Mickey Dunlap
05-17-2015, 08:36 PM
That muzzy looks nice, it should make a nice thump... Did you do anything special with the intake?

Doing port & flow work, but I'm building a customer a 2mm bigger intake valve and a 1mm bigger ex. valve. When I see what that flows I'll eith put a 300ex or a 400ex carb on it.
Mickey Dunlap
05-17-2015, 08:37 PM
Now that would be a dyno test to do. Before and after on just the pipe

No time to just do that.
oscarmayer
05-17-2015, 10:32 PM
Looks good. Now to tye in the other cylinder and you should be good to go.
For my Baja we ended up using a performance XR400 header assembly. Bolts on perfectly and larger than the stocker for sure.


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atcmatt
05-18-2015, 08:36 PM
Are these 350 big bore kits available to public and what is the damage?

Thanks
oscarmayer
05-18-2015, 08:52 PM
yes
http://www.3wheelerworld.com/showthread.php/174325-Honda-ATC-350x-500cc-BIG-BORE-kit-s-are-now-in-stock

this thread
Mickey Dunlap
05-19-2015, 01:25 PM
Are these 350 big bore kits available to public and what is the damage?

Thanks

Yes, the big bore with piston, sleeve and gaskets is $375. We have two different cams, then you need valve springs, clutch springs and should run my oil cooler too. Everything would be about $750 exchange on the cam.
oscarmayer
05-19-2015, 03:06 PM
oh crap sorry micky, i just realised this was for a bigred/sx not the 350x kit. sorry sir.