Carb swap

stv1jzgte · #1 09-05-2009, 02:56 AM

A little background to my story, My Gas man bike was second hand when i got it with 50cc engine. After a few months of riding i pulled the jug off and went at it with a dremel while i was at it i (laughing in hindsight) removed the step in the venturi of the carb opening it up considerably.
Well the bike went like the preverbial raped ape and it seemed that the engine porting incressed the max rpm's alot. this lasted about another 3months when the little end bearing failed and came back up
through the transfer ports scoring the bore and piston.
Enter the 50cc slant head engine only (plug threads blew out after 3 weeks, so not a slant head anymore) and no i have not opened it up yet.
In short the bike would not run cleanly with the same carb and was overly rich and i settled on a no#71 .6604mm or of you guy's .26" and she flyes. e clip set to std pos and im at sea level!

So today i Scored a brand new second hand nt carb std. set the float the same and put it on... way to rich, so i put my .6604mm jet in heaps better but still to rich at wot.
Do i try a .635mm or just stick with my venturiless .6604 carb setup?

stv

xlite · #2 09-05-2009, 09:24 AM

My advice, stick with the richer jet til break-in then get a smaller one or do the solder/drill trick to smooth things out at WOT.

So far .028" does a good job for me.

stv1jzgte · #3 09-05-2009, 10:22 AM

Quote:

Originally Posted by xlite

My advice, stick with the richer jet til break-in then get a smaller one or do the solder/drill trick to smooth things out at WOT.

So far .028" does a good job for me.

Yeh sorry i should have elaberated more as the motors 3 months old.
.28 is the stock size and to rich for my motor and i have done the soldering as im using .26
The only difference is the venturi, i think i will stick with it instead of the std carb.

xlite · #4 09-05-2009, 11:44 PM

Quote:

Originally Posted by stv1jzgte

Yeh sorry i should have elaberated more as the motors 3 months old.
.28 is the stock size and to rich for my motor and i have done the soldering as im using .26
The only difference is the venturi, i think i will stick with it instead of the std carb.

I assume you mean .028" and .026". Over quarter inch hole might cause some problems

.

2 of Mine were considerably bigger than .028" and ran smoother when brought down to that. The other 2 started there and although they seemed to bog less with .026" there was no power increase so put the original back in.

stv1jzgte · #5 09-06-2009, 12:54 AM

Quote:

Originally Posted by xlite

I assume you mean .028" and .026". Over quarter inch hole might cause some problems

.

2 of Mine were considerably bigger than .028" and ran smoother when brought down to that. The other 2 started there and although they seemed to bog less with .026" there was no power increase so put the original back in.

Yep you got me 0.26 or as i said .6604 of a millimetre.

xlite · #6 09-07-2009, 09:26 AM

Quote:

Originally Posted by stv1jzgte

Yep you got me 0.26 or as i said .6604 of a millimetre.

Still off by one decimal point.

stv1jzgte · #7 09-07-2009, 10:23 AM

Haha i think its your ****ty imperial system thats confusing me. its just you guy's left!

impression · #8 11-06-2009, 06:36 AM

Quote:

Originally Posted by stv1jzgte

Haha i think its your ****ty imperial system thats confusing me. its just you guy's left!

yep, imperial sucks.

Aus/Brit/Germ/jap/fren/chn all using metric...