NT Speed Carb vs Racing Carb

Sharif

New Member
Joined
May 28, 2019
Messages
17
This would be my first upgrade to my bone stock 2 stroke engine after the spring loaded chain tension I will be buying.

Wanted to know what's the difference between/which is better?

They both look different and the speed carb is known to be good or atleast I heard from an awesome guy locally.

The items in question
Speed Carb
https://www.motorizedbicycle.ca/nt-speed-carburetor-gen-2.html

Generic Racing carb I am seeing everywhere
 


Tyler6357

Active Member
Joined
Sep 28, 2011
Messages
620
I prefer the generic racing carb you have listed. Those are great carbs for these little engines but make sure you get some jets, you will probably need to jet down.
 

Lukesky36

Active Member
Joined
Oct 3, 2018
Messages
401
Nt carbs work great if you get the right one yes there is different ones you can get that look almost the same i have 2 that have different slide and needle sizes
 

Lukesky36

Active Member
Joined
Oct 3, 2018
Messages
401
I ran around 5 nt carburetors some are the same some are different its kind of the genuine nt carbs vs reproduction . some reproductions are trash and some are actually really good.
 

Tyler6357

Active Member
Joined
Sep 28, 2011
Messages
620
What do you mean by jetting down?
I mean, putting a smaller jet in the carb. Those carbs come with a #70 jet, however, most of the time it's too rich causing 4 stroking, usually jetting down to a smaller size jet will make it run at the correct air/fuel ratio. Often times when you get the carb you get THESE 5 extra jets however The stock size jet (#70) is usually too rich and the #75 and #80 are far too rich. If you really want to dial it in get a set like these----> https://bicyclemotorworks.com/product/jet-pack-combo/ You will need to test each jet until you find the right one for your engine. It's best to start high and work your way down until you find the right one that makes it run good.

----> https://bicyclemotorworks.com/product/fine-tuning-jets-high-60s/
----> https://bicyclemotorworks.com/product/fine-tuning-jets-low-60s/
 

gary55

Well-Known Member
Joined
Nov 27, 2012
Messages
3,273
Some of the speed carbs have a slightly larger slide, and stronger spring. Different NT types have different needle lenghts and notch counts. I prefer the real NT or the speed with 5 notches over some of the knock offs with 4. The Speed/NT's are more prone to floats sticking. The racing/ Dellorto clone carbs sometimes come as a 14/14, sometimes as 15/15, and tend to run a little richer than the NT's. They are all good carbs.
 

Sharif

New Member
Joined
May 28, 2019
Messages
17
I mean, putting a smaller jet in the carb. Those carbs come with a #70 jet, however, most of the time it's too rich causing 4 stroking, usually jetting down to a smaller size jet will make it run at the correct air/fuel ratio. Often times when you get the carb you get THESE 5 extra jets however The stock size jet (#70) is usually too rich and the #75 and #80 are far too rich. If you really want to dial it in get a set like these----> https://bicyclemotorworks.com/product/jet-pack-combo/ You will need to test each jet until you find the right one for your engine. It's best to start high and work your way down until you find the right one that makes it run good.

----> https://bicyclemotorworks.com/product/fine-tuning-jets-high-60s/
----> https://bicyclemotorworks.com/product/fine-tuning-jets-low-60s/
Seems like I am better off getting my hands on one of these kits before getting a new carb
 
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