I think I might be running rich...

[BeaverRat]

Hello,
I recently got my motorbike running very nicely (except for the fact that I may be running rich). It idles like a champ after I sealed all the air leaks in the engine.

What I have noticed is that the bike maxes out at about 32-33 mph on flat ground, but once i reach the range of 28-33 mph it sounds a little gurgly and 4 strokey. I wouldn't say that it is bogging, or loosing power. It just seems as if the tune of the engine changes a bit when I get into the top RPM's, and it is not reaching it's full potential.

Here is what I am running:

-66cc engine (straight head)
-ThatsDax RT Carburetor (on the .70mm jet)
-Opti2 Oil mixed at 72:1

Do I need to decrease my jet size even more (to a .68mm or .66mm size?) The jet is the only adjustment I have for mixture on this carb... If I in fact do need to decrease the size of the jet, how would I go about doing this? I would much prefer to just buy a new smaller jet (where can I buy one?) than re-solder and re-drill the current one.

I guess my main question is: Where can I buy a .68mm or #71 size jet for the RT Carburetor?

Thanks

 

[Greg58]

remember the higher the drill number the smaller it is, if you are not running a high flow air filter you can help it with one. Have you done a plug read to see where the mixture needs to be? I am running a 48cc grubee and had to drill my jet to a #66 before mine performed like I wanted, this is on a cns2 with a SBP air filter, the stock size on mine was a #70 and it ran well with the stock air filter. If you can increase the air flow it will compensate for the jet size.

 

[droc089]

Duane sells them on thatsdax, there on the bottom of page one 1 in parts. But there's two sets M5 and M6. They both say for RT carb though