mph issue

GoldenMotor.com

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,837
252
63
up north now
Sure, it's possible, but I really don't think it's a restricted fuel flow issue, because these carbs don't need that much gas flow; & if the flow was restricted at WOT, wouldn't it just keep getting leaner & leaner until the engine just shut down or burned up?
I'm just guessing wildly and theorizing.... I would think it runs good, then as it leans and sloes down the flow "catches up". I have seen how much fuel some of the petcock DON'T flow, and it's enough to starv the engine in some cases.
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,837
252
63
up north now
This thread IS all over the place! So......A few things then I am stepping out of this one....

Always make sure your engine is properly tuned BEFORE you start adding go-fasters. It doesn't do any good to add "performance carbs" ect. if the engine isn't set up and running right to begin with.

I think there is a confusion on this thread (and others) about what the subtle but HUGE DIFFERENCES between "surge" "bog" and a blubbering rich "four cycling" condition are.

Those kinds of things need to be sorted before any long distance diagnosis can occur.

Finally,
Black, oily=too rich move the C clip UP a notch.
White or gray plug=too lean Move the C clip DOWN a notch.
The "notch" being the different needle clip settings, the needle clip being on the slide needle.

If you are unfamiliar with those items and their location, you should go back a few steps, and read up on these and gain some basic knowledge BEFORE you start "fixing" you engine problems.
 
Last edited:

momentummotorgroup

New Member
Apr 10, 2009
198
0
0
grand rapids, michigan
i'd say if you want more speed AFTER you get the thing tuned right you should go for a smaller rear sprocket. Every tooth under 44 lost is 1 mph gained according to the folks at Kings Sales and Service (found midway down right side column)... whereas your time to get to top speed increases from lower torque as well as loss of strength on hils, you will get a higher top speed, I have a 36 tooth sprocket from them on one of my 49cc Grubee builds and it is pretty nice.