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my98mugen

68s

12 posts in this topic

quick question.

i reallize when you uncork a brp you go from a 65s to a 68s. but what is better, a 68s or a regular 68. i realize that the regular 68 has the larger holes, isint that better for better mixture? it seems like everyone is putting in the 68s.??????????????????????????????????????????????????????????????

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There is no single best to suite everyone. You'll have to try them both to find out which one is best for you based on the specifics of your bike, your riding conditions, your riding environment, etc, but generally the 68's or 70s is the pilot jet that many find that works best for them in the SoCal deserts on a stock uncorked bike.

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also, uncorked is 68s and 175 main. so what about when i put on a full exhust system...... what do i rejet to?????????????????????????????????????????

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The air jet in the intake side of the carburetor suplies the air to the emulsion holes in the pilot jet. The air jet is not changable on the stock carburetor and is setup for the smaller emulsion holes that are in the "s" pilots. Going with a non "s" will atomize the fuel with more air leaning out the mixture just off the bottom. This will also make the air jet cut off valve have a more noticable transission but, plugging the AJCV is an easy fix. I did not try it back when I had a stock carburetor but, going to a 70 non "s" would be a better idea then going to a non "s" 68.

http://www.borynack.com/Bruce/XR650R/xr650r_caruretor.htm

http://xr650r.borynack.com/

178 main and 70s pilot for a free flowing exhuast.

http://www.borynack.com/Bruce/XR650R/HorsePowerMods.htm

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thanks, that brings me to my next unanswered question. what excactly dose pluging the AJCV do???????????????????????????????????????????????????????????????????

ive read your page about the AJCV and what it does, but waht is the advantage of pluging it????????????????????????????????????????????????

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It gets rid of the slow return to idle, Helps on decel on down hills due to no hanging idle, Have you opened up the side cover yet......... :)

Better yet go with a Edelbrock carb..... :D

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When I uncorked mine the I went to two Honda dealers and neither had a 68s. When I gave them the part number from the uncorking articles they said it just showed as a 68 on their computer. We dug through their box 'o jets and only found the regular 68. So, that's what I put in.

Sounds like I need to track down a 68s....is there a different part number?

Xr's only sells the Mikuni pumper. How does it compare to the Edelbrock?

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i bought my 68s from a honda dealer. it was packaged separately from honda and not with the other bulk jets.............it was about 12 bucks..... gl.

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The Mikuni TM40 is more adjustable then the Edelbrock making it way smoother. It's is a better carburetor once tuned and that is what makes it a pian in the rear for some. The Edelbrock tunes real easy. Nothing is easier. The edelbrock will handle great elevation changes and if it does get to ritch you can lean it right on the ride. I have ran the Mikuni TM40, Mikuni HSR42, Edelbrock 36mm X 42mm (stock edelbrock for the XR650R) and a bored out Edelbrock 40mm X42mm. The TM40 is the smoothest, most linear giving awesome responce and tuned right more power then a stock Edelbrock but, a bored out Edelbrock allows for a bigger power gain after 3400rpm on my 680cc bike. I do not like the jetting setup that the TM40 kits for the XR650R come with.

When odering a pilot jet for your XR650R have them look it up on the fitch. They will see the 65s and the 68s option right there and the part number they need to use. 68s pilot jet 99105-MBN-0680, 70s pilot jet 99105-MBN-0700 .

http://www.borynack.com/Bruce/XR650R/dynocharts.htm

http://www.borynack.com/Bruce/XR650R/HorsePowerMods.htm

http://xr650r.borynack.com/xr65rstuff.htm

http://xr650r.borynack.com/

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It's amazing how little most of the dealers actually know about the XR650R. I have repeatedly informed my dealer of the latest information. They listen to me and get what I want. Half the time I know what the next secret bike is before they do just by reading the magazines and keeping up with the gossip on this list.

My dealer no longer stocks the XR650R on his showroom floor cause he can't sell them. I have bought two from him and will buy a third if the rumor of an electric start model never materializes.

All these jet sizes are on their diagrams in their computers. I purchased both the 68s and 70s from my dealer no problem.

A pumper carb is the way to go but if money is tight just be patient and keep working with the stock carb until you get it right. It is a decent carb once set up.

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I don't know man, I still have the stock pilot jet in there, bike is uncorked, and does have the B3E needle, 180 main jet, and airbox drilled. No problems with how it runs, enormous power, but it is a little hard to start sometimes.

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