Carby NT Carb Tuning Basics

Only you can answer that. Do plug chops at mid and full throttle to determine what you need to do, (as described earlier in this thread). This thread is getting really messy and repetitious. I won't respond here any more.
 
god i miss my rocksolid hp2 50cc coated piston an dellorto (clone) carb ...
i have a bike just need a front 53mm mount ..
......
brad sydney



yerr i love dellorto ...



most informative as per usal ....
let u know when i get mount ..:bowdown:

.
 
POS! :rolleyes:

ok, yes, it does the job until i find a mikuni 18 2nd hand... (all the good old moto wreckers have vanished!) or see if a diaphgram carb can run with gravity feed and no pulse... or make a pulse feed. and when i make my mind up what to do :)

but, ive had a tinker and got out the old chisel :)

mods i did.

machined the throat! its now a nice taper from the inlet to the face of the slide. increased venturi effect rather than the standard parrallel throat.

made a new jet! lathes are handy and so are multiple parts :) and 0.05mm increment drills....

so, for my application, zbox 48, ive found !!!!!!! 0.6 to 0.65 ideal !!!!!!, down from...0.78? iunno. bigger than 75 smaller than 80... big difference :D especially on fuel consumption...

bashed the choke flap bolt/nut so it doesnt come loose... yes, could remove and plug the hole...im lazy when i gotta be elsewhere!

um....

had to do more than bend the tangs on the float needle. found they hit the brass inlet barb! the needles groove was too wide, so...trim the brass barb!

thats it. :cool:
 
Howdy, HeadSmess. I machined the same taper into the inlet of my carb.
0.6 to 0.65 sounds about right for a 48cc. My (ZBox) 66cc loves an 0.72mm. The stock jets in the ZBox carbs are 0.79mm - huge.
 
id like to try tapering the other side as well slightly but its a little tricky on my lathe to setup...

good to know someone agrees with my findings though :)
 
I got tired of messin with that crappy carb. I fabricated my own intake manifold, mounted a chainsaw carb. Runs PERFECT! As if it was fuel injected! Bike could run upside down if I wanted. If ya need pics folks, just ask
 
interesting and definitely a good idea...mmmm, adjustable hi/lo needles :)

but....how did you get the pulse for the diaphgram pump in the carb?

im assuming you did use it, else it wont run upside down...

im not even sure if they will run at all without the pulse. ive never tried, anyways.

nice to know if they can though :) makes life slightly easier...
 
I replaced my old carburetor with my new carburetor.., because the old one was cracked.

HERES MY NEW PROBLEM. PLEASE READ.

Now, everythings hooked up and all, but, now the throttle doesn't really respond like its supposed to..read on.

I mean, I can pull in the clutch, then release it, and it will start! WITHOUT EVEN touching the throttle?


It seems like the throttle can move something in the carberator to adjust my speed.., but it gets stuck..

So I was stuck at the highest acceleration and couldn't stop unless I pedaled backwards or hit the clutch again. Was kind of scary.

PLEASE HELP. is the needle getting stuck or the throttle not set up right to the carburetor?
 
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