lets talk carbs motor set ups... size where do they help

[woodsracer144]

ok... i am left thinking and i dont get it...

for low end how does a 35 or a 36 mm carb help you get more low end? wouldnt a larger carb allow more air allowing more gas as well and then in return allowing more power? i'm looking for a goos solid low end set up for the woods but im running a 38 PWK right now..

also how much does the high compression help you in a 2 stroke over a 4 stroke...

all the dynos' i've seen are on 4 strokes that were tested and the result was that you gained very very little at the most like 7Hp.

so is it the same with the 2 strokes?

[kouki]

When you are talking about a small displacement engine such as a 250cc 450cc etc, 7 hp is a pretty good gain. As for smaller carbs for low end and larger carbs for top. Well on top end in the high rpms your piston is moving faster, so the larger carb is less restrictive allowing more efficiency when pulling in a high volume of air, allowing more power in higher rpm. In lower rpm, with a larger carb you are not making full use of the volume that carb is flowing, and that is in effect restricting your performance.

[woodsracer144]

How much hp is gained on 2 stroke motor with race gas ?

[1promodfan]

Originally posted by woodsracer144
How much hp is gained on 2 stroke motor with race gas ?

I'm not sure of the HP gain, but by running a race gas dome, you'll have more compression. More compression will give your bike a little bit more low-end grunt. I'm thinking of changing domes just for that reason.

[woodsracer144]

what do you think of running E85 in a RACE motor meaning high comperssion and all that... theres people on here running it on there 400ex with 13-1 and 12-1 pistons... for those who dont know its like a 105 or a 115...

[wilkin250r]

Smaller carburetors have higher intake velocity. This is obvious, if you're running at 3500rpm, the air will have to flow FASTER through a 36mm than it will through a 38mm, but it's not really "restrictive" yet at such low rpms.

That higher airspeed is the key. It gives you better throttle response, more accurate fuel metering, and better atomization of fuel for a better, faster burn.

Think about it. If bigger carbs were always better, than wouldn't we all be running around with 80mm carbs on our quads? Smaller carbs are restrictive at high RPMS, so obviously larger carbs perform better because they flow more. But at low rpms, when you're not flowing enough air to cause any real restriction problems, smaller carbs perform better.

[woodsracer144]

so what size is a stock carb? whats the best 36 or 35? make like just a pwk?

[1promodfan]

Originally posted by woodsracer144
so what size is a stock carb? whats the best 36 or 35? make like just a pwk?

I could be wrong, but I think a stock carb. is a 34PJ. If I'm wrong someone feel free to correct me.

[mxduner]

Originally posted by 1promodfan
I could be wrong, but I think a stock carb. is a 34PJ. If I'm wrong someone feel free to correct me.

i believe you are correct

whats the best 36 or 35? make like just a pwk?

they make a 35 pwk a/s or you can go with a mikuni tmx 35,36 tmx, which is not a favorite to some cause of jets availabilty. I own more mik jets than kehins seems sleds have mainly run them for years.

[woodsracer144]

what are some of your carb settings and motor set ups and stuff