Performance Carb Upgrade

ok i bought the dertollo carb and i particular noticed at low end the idling was much stable and running perfect take of and starting has improved and also their is no "fuel starving" at top speeds i noticed exatclty a 7 km increase in speed:) worth buying
 
I bought the 14mm dellorto SHA replica and absolutely hate it. It ran very rich out of the box. I bought a set of jets but they were all bigger than the stock jet (that was my bad I should have paid closer attention). So, I soldered and drilled the smallest jet. No matter what I did, I could not get the thing tuned across the entire RPM range. It was either lean in the high end or rich in the low end. I finally gave up and switched back to the stock carb which is still a little lean at WOT but much better than the dellorto knock off.

Spooky Tooth finally got the CNS carb in stock so, I ordered that thing immediately. I should have it by Tuesday or Wednesday. I'll post my results as soon as I get the new carb installed.
 
Hi bigdan

Your experience with the Dellorto SHA replica is exactly the same as my experience: ran far too rich even with a smaller than standard jet, being a No .072

The carburation was never smooth through the rev range; only being relatively good at low rpms but everywhere else it was overly rich.
In the end i gave up on the thing and went back to a standard NT carburettor on a Rock Solid Engines, billet intake tube.
This combination works reasonably well but it's still a little on the rich side from 4,000 rpm.

Programmable laptop interfaced digital fuel injection is the only way to go and the only person selling a perfected system will be Rock Solid Engines.
Release date is to be January 2010.

Fabian
 
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Spooky Tooth finally got the CNS carb in stock so, I ordered that thing immediately. I should have it by Tuesday or Wednesday. I'll post my results as soon as I get the new carb installed.

Hello bigdan, I'll be watching with interest to see how the CNS carb goes.
Rock Solid Engines have a Mikuni for these engines, so if the CNS carb doesn't seem too good I might lash out and buy one - see if it's better.

Has anyone else bought the Mikuni?

... Steve
 
ive bought the CNS style one from zbox when they had them but there not so great either, they give you a bit more bottom end but the top end is lost.
 
Anyone try the racing carb from pirate cycles?

Do you know what make it is? They only describe it as 'The Racing Carburetor'.
A pic:-
yhst-10337746512064_2083_460997


This put me off, (the red is mine):-
Note: This kit requires additional clearance in between the air intake manifold and the bicycle frame due to it's length. Not much is known about these carburetors and no additional specifications are available at this time from the manufacturers
This is a aftermarket Racing Carburetor for the Chinese two stroke bicycle engine. This carb will require some tuning to reach optimal performance.

Won't fit most bikes without mods and might be hard/impossible to get jets and spares. Still, I wonder how they perform. (I'll try almost anything to make my engine run more like a Japanese one.)

... Steve
 
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That i'm not sure of either.
I think the extra length is required cause of the air cleaner.
If you can fit a dellorto i think it would fit.
I'll give Justin a call and see if i can find out.

All these carbs need tuned.
And truthfully i get my 48cc going 45mph 36t singlespeed with the stock carb.

Idles terrible cause i got to run it rich but once i'm movin watch out.

Thats really what we need ... a more tunable Carb.
So we can really dial in the mix.
 
Ahhh.
I seem to hear that about all of em.
A few have good luck.

Thats why i wonder about the new stock grubee SPEED Carb.
Possibly better???
 
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