First of all whoever designed a carb that you have to remove it to turn the air screw should be shot! Jeting cahnges arn't real easy because it requires removing the plastics, tank, and other stuff, what a design! According to my dynojet instructions I should run a 170 main with no lid and a 146 with a lid. Can this really be true?? What a difference! It runs good with out the lid and a 170 but I have to put the lid back on (MUD!)Will I really have to go to a 146, leaner than stock(150)!!!!! Please help me out and tell me your mods and jetting. Also I have a Dynojet needle on the 3rd notch, like the book says. Thanks boys!!

 

First off, just FYI you did way more work than you had too. All I did was pop the rear plastics off and loosen the carb. You then twist the carb so that the bottom is more angled towards the left of the machine (clutch side). By doing this you have ample room to swap jets all day and night. As for the mixture screw you twist the carb to a more normal postion and what I used was a 1/4 flat head bit as a screwdriver. Never removed card, front plastics or tank. Took me no more than a half hour just to be on the safe side now I can do it in a couple of mins. As for the jetting you need to consider elevation and any other mods. The more fuel the more air and quicker evacuation (exhaust) you want. My bike with the 170 would break up and backfire even with the K&N (lid on) Drilled holes in the lid and it ran great. Add a Yosh pipe and silencer and it f'n flies. If you have no mods at all and want the lid on try maybe a 160. You need to just play with it that's all.

 

man you made a short job long. you think its hard on a 400ex the 300ex jeting is a pain its right under the gas tank

 

300ex is easy..just get a combo wrench..

a socket and a pair of needle nose vice grips.

you can change them in a few moments

 

i found it quite hard

 

I added a pro circuit pipe but my local dealer only had a 155 main, it seemed to run ok but i was not that much faster than stock. Did you change the needle postion in the carb. All i did was flip the carb upside down and it was easy to get in there and change the main. I think i should go with at least a 160, i mostly ride at sea level. Sometimes i take off the air box lid but gotta watch the mud.

 

OH yeah! My stock main was a 148 not a 150.

 

Doesn't dyno jet use a different number system than the stock jets?

 

I bought mine used but the previous owner said he never touched the carb. It had a 150 main in it, did anybody elses come with a 148?? I found if I unhook the fuel hose, vacumn line, intake hose, loosen the front clamp, Remove the two rear bolts in the front plastics, lift up on the tank and I can wiggle the carb out to change the jet. This is a little easier, the throttle cable limits the movement though. I found that the 146 work good with the lid on. I couldn't beleive it ran so well with a 146 when stock is 150 and I have a white brothers pipe, 440 kit and lots of other stuff. It works good though, and a 170 with no lid is great, just like the dynojet instructions said. Also does the air screw make any difference, it's hard to tell sometimes. Right now it's perfect with 170 and no lid, throttle response is instant and 5th gear wheelies are easily attainable. Now it's in the 20 degree range out here in PA, does the cold affect it??? Should I go richer or leaner for cold. How do I know when it's just right? I was told to keep going bigger on the main jet until it skips at high rpms and then back it off one size, 170 is the biggest I have but maybe I should try a 175 or 172. Are dynojet jet sizes the same as Keihin jet sizes or are the numbers different. Thanks

 

I agree, it's a pain especially when the intake boot clamp is overtightened from the factory, and so you strip the head of the screw trying to loosen it, and ultimatly can't get the fuel bowl off because you can't get it the carb off the boot. But, that's not necessarily a Honda problem, but I'd love to shove my screwdriver up the rear of the retard that put that clamp on.