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Boring out carb

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I've read about the possbility of boring out a carb for more flow. Who can do this?

It's my understanding that my Mikuni TM36-50 still may not be enough carb for my 440. Tho it runs great, I'm wondering just how much the throat can be enlarged and run reliably.

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I know people bore out the throttle bodies on cars, pretty sure they just use a dremel. I'm sure a carb on a bike isn't much different.

No idea on how much to go though.

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Try reading "little women" or showing the movie "Picnic at Hanging Rock" to your bike. That's enough to bore ANYTHING!

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..er yea, I'ld assume you're smart enough to know that you should'nt go after it with your Dremel.

Looking for an oval bore?

Flat sides look like they might be a little up there.

http://www.thecrankshopvt.com/item.asp?item=CARBBORING

..or talk to this fella about vortexing. I think it sounds like a better idea,

http://www.fueltechusa.com/price.htm

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Seriously, save the carb, and buy a larger bore carb if you think it's necesary. Supposedly, smaller bores give you better bottom end (more velocity) while larger carb bores help more on top end power. However, if you are looking for more top end, have you tried a Hotcam or other aftermarket lumpy cam and a large diameter head pipe? Do this other stuff first, then go with a bigger carb if the bike still wants more air.

If you must bore out the carb, then get it to a machine shop with a milling machine. They can set the carb up and bore it out using a boring head. DO NOT USE ANY HAND TOOLS, DREMELS ETC... unless you just want to see how fast you can trash a carb.

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Better yet, buy an XR650R. I used to have an XR400, I loved it... until I twisted the throttle on my XR650R...

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Thanks all, well, not all. lol

I wasn't about to touch it with a dremel. I like the low end torque it has now and I don't ride that fast, so I guess enlarging the carb is unwarranted.

I've ridden a 650R, too heavy and the power is insane.

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Sorry for the 650R jab, I couldn't resist.

Seriously, I put on an over sized header on my 650R not long ago. It made a noticeable difference. The bottom end was a bit softer, but the bike really made power all the way up to the rev limiter ~8200RPM. With the stock header, the bottom end is snappy, almost harsh, and the power falls off quick after ~6000RPM. I ended up going back to the stock header, because I missed the bottom/mid power, however, I did like the extra power on top.

Typically with big bore kits, such as your 440, or the 680 kit for my bike, you gain lots of low end power/torque, but nothing on top. A header may be a great deal for you, as it will allow the bike to make more power on top and thus balance out your power curve. Give a header a shot, the sensation of the bike continuing to pull well into high RPM's is exhilarating.

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