whats the point of a bigger carb?

PimpinSpree · Post by **PimpinSpree** » Fri Jul 11, 2008 11:31 pm

whats the difference between getting a bigger carb and just putting a bigger main jet in a stock carb?

burnt_toast · Post by **burnt_toast** » Fri Jul 11, 2008 11:47 pm

Better flow and adequate supply of A/F to a big bore engine.. bigger carb not needed on stock block

PimpinSpree · Post by **PimpinSpree** » Sat Jul 12, 2008 12:04 am

so if i do i big bore do i def need a bigger carb?

what about a spree carb with a bigger jet on an se50 elite motor

Kenny_McCormic · Post by **Kenny_McCormic** » Sat Jul 12, 2008 12:20 am

Spree carb on SE50 will be underpowered at best.

GN Racer · Post by **GN Racer** » Sat Jul 12, 2008 1:41 am

PimpinSpree wrote:so if i do i big bore do i def need a bigger carb?

Not necessarily, but you will need a larger jet for sure.

PimpinSpree wrote:what about a spree carb with a bigger jet on an se50 elite motor

Open up the carb a bit with a grinder (after disassembly). Not too much though. You can open it up to the stock SE50 size, or larger. I used to run an opened up Spree carb on my '87 Elite engined Aero with a 62cc Proma kit. I think the jet size I used was a 90 or 95

I later upgraded to a 18mm Mikuni w/Kitaco manifold, but I don't remember if there was an improvement in performance. It's still on there so I know that it didn't hurt performance.

PimpinSpree · Post by **PimpinSpree** » Sat Jul 12, 2008 2:07 am

what do you mean open it up? I've never heard of doing this, so i can only guess. Like grind off some aluminum where the butterfly opens up?

GN Racer · Post by **GN Racer** » Sat Jul 12, 2008 2:40 am

Yes, grind, file, Dremel to flow more air. Not too much though, and definitely not on a stock bike with no mods. Also FYI, there's no butterfly, there's a slide.

Although it's pretty easy, I would not recommend doing this if you've never done it before. The carb has to be completely disassembled, and you have to be careful not to overdo anything.

If you do run the Spree carb, don't forget to swap out the slide as well. It will be different. Also, don't worry about the bystarter; Just leave it unplugged. You will not notice a difference. Don't forget to re-jet! Always better to be rich than lean!..

When modifying your bike, do ONE modification at a time whenever possible. That way you can determine if it made a difference or not. It also makes tuning much simpler...