Dont be mislead by Main jet sizes, just becuase the carb is bigger, doesn't mean it has to have a larger main jet. If the carb flows at a much better rate, it will use a smaller MAin jet. The better flow is alot more efficient, So the added velocity can get alot more fuel out of a smaller opening.




bigger.

 

uhhh... whatever you say, dude.

 

Guess I got a little carried away with my mm's.

 

EXAMPLE:

The Stock DS650 has a 42mm Vaccuum slide carb, at close to sea level elevation the optimium main jet for this carb around 185(mikuni)
NOW, when switching to a HSR45mm carb(flat side) the optimium main jet size for the same bike at the same elevation is 155(mikuni).

The HSR45mm flows at a much high velocity than the stocker, therfore it doesn't require a large main jet. make since??





Bigger.

 

the vinson has a two part carb, the slide, and the vacume, that opens via air pressure flowing through the carb is what i belive, i have played with the jetting alot, and got it where i want it i am on the 3rd clip on my adjustable needle, and 138, and 2. 3/4 turns on the air screw, i belive that the eiger should run a little leaner with the bigger carb, being that cvk36 can flow alot more fuel than the eigers 32mm, so it makes sence to use a 136 or something, but if you said it was lean, and the stock is 144, then try a kehnin 146-150. remember that dynojet #s are different from kehnin #s, i have a conversion chart, i gotta find it and i will post it.

v581

 

Thanks V581.

I never got a chance to pull my float bowl and check my stock jet. I know the Dyna-Jet numbers are significantly different than the Keihin #'s, so unless that conversion chart of yours turns up....

It always makes me laugh how some of the ATV people that don't have much experience with tuning trucks/cars have such crazy misconceptions about adjusting carbs, or timing, or even basic concepts like lean/rich running conditions.

I guess even if I didn't ride quads ever again I'd still come here for the entertainment value.

 

true, i understand, belive it or not i learned alot of my tuning skills from my race r/c cars i had over 1500$ in one, and then thought that they were to expensive, and wanted to try a different hobby, hmm quading doesnt seem cheaper....... oh well now i do both, just need to get me a z and start racing quads, i agree with people who dont understand lean and rich, and then do alot of babbleing, there are alot of people like that here [img]i/expressions/face-icon-small-smile.gif[/img]

 

Yeah, I talked to an acquaintence this weekend about the Z400. He owns a YFZ450, and rode his friend's Z, and didn't much like it. He said it was kinda gutless (comparitively) and was too short.
Too bad the YFZ is so damn expensive.

 

Pulled the jet out of my new carb (36mm), and it IS a 128!! So, I swapped in my 134, and it seems to make a slight difference. Starts even better than it did with the 128, which is an improvement over the stock carb. It's hard to imagine it starting up faster than with the stock carb, but it seems like it starts in less than a single revolution now. Never need the choke, (it gets into the lower 50's here at night, and before I would need about 1/3 choke for it to idle for the first minute or so), and it runs like a raped ape.
Still doesn't go 60mph. I think it's restricted by the exhaust, as the revs are REALLY high at 55 or so. I'm thinking a new exhaust is gonna push me over 60, but above that is questionable, as I'm not sure if the CDI will support that kind of engine speed. Even when I rapp it out in 2nd gear it doesn't sound like the RPMs are higher than at top speed on level asphault. And, realistically, WTF would I want to go faster than 55-60?!? Am I going to be riding this thing on the highway? I think not. Even at the dunes, 60 is fast on a util. One dropoff or hole and I'd be toast.

 

Aksafari, great post!!!!!!!!!!!!!

I've been out riding the last couple weeks so I've missed some things.

Get the 26" mudlites!!!!!!!!!! I LOVE em!!