need jetting help on my 350x

[3leggeddog]

well with the harescramble next weekend i wanna make sure the 350 is gonna fry,i pulled a plug yesterday and it was white.so i pull the carb and pull out the main jet.it has 14ord stamped on it.wtf is that?i call my local shop,the guy loves 3 wheelers,and he has never heard of a jet with these numbers.is this an aftermarket jet kit?what size is it equal to?

where do you guys think this should be at.i got a dg chromepower exhaust,uni filter,airbox lid on?would a 142 be good?what about the pilot?,and clip position.

thanks guys.

hehe,i just looked at the jet,i bet it's a 140rd,still what is the rd?

[SpeedBump]

Sunday is almost here! It is gonna be cold too. If the plug is light/white you are lean and I would almost certainly bump up the main some. It sounds like a standard 140 Keihin size. Not sure what the RD would be, but the 140 is about right. My 300EX ran a 138. I think I bought a 145 and tossed it in the 350X when I did the conversion. As for the needle, I would richen it up too. It is a PITA, but you are gonna be pounding on it for a long race, so it would be better to be a bit rich. I don't have any jets that small anymore...I think 160 is as small as I got. I would say toss in a 150. Not sure on stock size, but with your Cobra, sounds like it needs a bit more jet anyway, even without the temp changes.

[TravEX]

I've got a 142 I can ship you tomorrow.

[NOS_350X]

i would go with a 145 main, 42 pilot, and move the needle clip up one notch from the middle.

[max]

i have a brand new carb rebuild kit for it. it has a couple of jet. i can bring it with me if you want.

[Blown 331]

i would go with a 145 main, 42 pilot, and move the needle clip up one notch from the middle.

I got the same basic set up on my 350X. I have a 138 in it now and I have a 150 sitting around. How much of a differnce in jetting does it make when you take the air box lid off? I know on a 450 you go from a 118 to 185, I assume it's nothing that drastic but do you have a rough idea at all so I know what jets to buy?

[hoser]

I got the same basic set up on my 350X. I have a 138 in it now and I have a 150 sitting around. How much of a differnce in jetting does it make when you take the air box lid off? I know on a 450 you go from a 118 to 185, I assume it's nothing that drastic but do you have a rough idea at all so I know what jets to buy?

Is that normal for that bike, that is a huge jump going from a 118 to a 185 sounds like the carb has lost its carb signal (ability to pull the fuel out of the carb) to compensate you had to go big bet the gas just dribbles out the jet this usually leads to fuel puddling and a lost of power some where along the way, how ever the cool sound you get from the intake noise usually mentally fools the owner into 'feeling' they now have more power.

It would be cool to put the bike on a chassis dyno and switch from a 118 to a 185.

The intake tract is engineered just like the exhaust system...

On a side note I have seen guys smoke their engine by removing the factory intake system and installing just a clamp on filter, they jet the engine until the plug says its fat (almost black) then the first time they load the engine up to the max usually a long steep up hill run it leans over poofkaboom, the loss of or weakening of the carb signal has shown it ugly side but only under certain conditions, the owner usually never figures it out and just keeps feeding it parts and going bigger on the main jet.

[Blown 331]

Is that normal for that bike, that is a huge jump going from a 118 to a 185 sounds like the carb has lost its carb signal (ability to pull the fuel out of the carb) to compensate you had to go big bet the gas just dribbles out the jet this usually leads to fuel puddling and a lost of power some where along the way, how ever the cool sound you get from the intake noise usually mentally fools the owner into 'feeling' they now have more power.

It would be cool to put the bike on a chassis dyno and switch from a 118 to a 185.

The intake tract is engineered just like the exhaust system...

On a side note I have seen guys smoke their engine by removing the factory intake system and installing just a clamp on filter, they jet the engine until the plug says its fat (almost black) then the first time they load the engine up to the max usually a long steep up hill run it leans over poofkaboom, the loss of or weakening of the carb signal has shown it ugly side but only under certain conditions, the owner usually never figures it out and just keeps feeding it parts and going bigger on the main jet.

That is normal for that bike. That is even what the HRC kit consists of, it's just really choked from the factory. They have a 42mm carb and the air snorkle is the size of a quarter.

[3leggeddog]

i put in a 142,it was the closest i had.next jet is a 158.i will do a plug check this fri and see whats up.