Carburetor upgrade

[joshstep1]

I've been looking at a 30mm pumper carburetor for my Carbide. What does this thing do? Why is it better than the 24mm carburetor that it comes with?

[GX150]

More air and fuel can get into the engine on each stoke due to the larger size carburetor. Since it has a pump, it responds faster to throttle change than a vacuum slide on its own.

[joshstep1]

Wow.

[joshstep1]

It would be about $260 for the whole kit. Would it be worth it?

[BuggyMaster]

You also need to consider if you really need all that carb. In a lot of cases, people get the bigger carbs because they have modded their engines and the need for more fuel than the stock carb can provide is present. i.e. the stock carb can't deliver what they need.

[GX150]

28-30mm works well on the GY6. Even an intake, exhaust or cam change may increase the need the for additional flow, so don't think you have to do major top or bottom end work to benefit from a 15-20% larger carburetor.

I prefer mechanical slide carburetors, but the jetting is more sensitive to temperature and elevation changes. If you're willing to rejet based on conditions or you ride in similar conditions most of the time, this is not an issue.

[SYCARMS]

If you want more performance go with a cam,rejet, and a better exhaust. I have a 63mm bore 6mm stroke a killer cam that don't like to idle and run a 30mm. My son has a 62mm bore 2mm stroke and 4 valve head and he runs his stock carb 26mm. The cam will make a bigger difference then go with a 26mm instead of the 24mm. Cheaper too.

TOM

[joshstep1]

I've messed with the cam before... I don't have good experiences with that haha... what does the cam do?

[SYCARMS]

Opens the valves.

TOM

[ckau]

A couple of things you need to consider about that 30mm pumper. The carb will fit to the motor fine with a 30mm intake but will it fit in the swingarm frame? The 30m intake sits at a slightly higher angle than the stock so you may find a crossbar blocking the inlet. In a yerf and a dazon we had to omit the heat spacer and bolt the intake directly to the head to barely get enough clearance for a velocity tube and air filter. It's tight! The external pumper circut also hits the passenger side motor mount so the carb has to sit at a slight angle. The carb works great after you adjust the float level to account for the slight angle. The stock throttle cable has to be re routed at a different position too so you may find you will need a longer cable.
That carb flows 20% more air volume so if the stock exhaust can't flow accordingly then you won't feel any real benifit from the 30mm carb other than maybe a little better response when stepping on the gas. it's not good when you have too much air going in but it can't get out. you may find your loosing power at higher rpms. The 30mm realy gives a nice punch but figure on upgrading the exhaust as well.
$260.00 is preety steep for this carb. I am using three of these and they work great http://cgi.ebay.com/ebaymotors/30MM-...item588f7a43d1

[joshstep1]

Wow, that's a lot cheaper... and I already have an aftermarket exhaust. I have an FMF slip on. Look at my signature of the list of my upgrades. Would the fmf work?