cns carb v.3 tuning

ok if somebody carried a good quality tuneable carb that will fit my 48cc skyhawk,ships to canada and does take some form of credit card payment,who should i contact?
 
Thatsdax.com should be able to help, He is one of the sponsors on the sides of this forum.
 
Well i figured out how to get my cns v3 running correctly. On a bunch of 48cc grubees i did for a customer, what i did was solder the main jet and drilled it to a #70-#71, i pulled the plug covering the idle mixture screw and started at two turns out, also what makes a big difference is removing the magnet from under the left engine cover and cutting a new slot to get it timed right. I have a non grubees motor that just runs perfect so i copied the timing it had and presto!
 
Oh yeah the stock cns v3 seems to come with a #65-#64 size jet which is way too rich for the 66&48cc engines that's why i soldered and drilled em.
 
I had some friends that used to go to the mountains and ride motorcycles. They would all carry a few strands of real fine copper wire. They put a strand of that wire in the jet and then wrap the other end around the jet so it wouldn't go all the way through.

Then when they came back to the lower altitude just pull the wire out. Not sure if you could do that with a cns carb or not since I've never seen one, but thought I would throw it out here....
 
i'd be curious about re-timing also.

motoxjosh-zoom sells the same carb im running,so it would be the same thing.
i sent dax a mesasage,waiting for a reply.i want one of his carbs.

i did try the copper strand in the jet,maybe the strands werent thick enough as i really didnt notice a difference.
 
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Nah...

Copper strand in the jet ain't gonna cut it...
Sry.
Fax is fax.

Better to set it up lean for the low flats and it will come around on the climb.
Just don't burn it up down low!
rc


Actually, it would not be too difficult to loosen the carb clamp, rotate the body, drop the bowl and exchange the main jet... for the thin run...

Basic facts are you're gonna lose 10% hp per 1,000ft asl anyway.
That's why aircraft run superchargers.
Starting with <2hp, there ain't much going on from the gate! :-)

Best
rc
 
rustycase said:
Nah...

Copper strand in the jet ain't gonna cut it...
Sry.
Fax is fax.

Better to set it up lean for the low flats and it will come around on the climb.
Just don't burn it up down low!
rc


Actually, it would not be too difficult to loosen the carb clamp, rotate the body, drop the bowl and exchange the main jet... for the thin run...

Basic facts are you're gonna lose 10% hp per 1,000ft asl anyway.
That's why aircraft run superchargers.
Starting with <2hp, there ain't much going on from the gate! :


Best
rc
Click to expand...



So you have tried the strands of wire? And my airplane does not have a supercharger....:D.trlrl.
 
Good thread, I should try my bike's first start up pn Saturday. My carb is the cns v3 and has the same "sealed" cap. Drilled a small hole then screwed in the tip of a corse screw and it pulled right off.dance1 Thanks.



Now, how should I turn the adjustment screw before I turn it on?
 
No, ilikeabikea, I have NOT tried sticking a wire in a cns main jet.

but I DID solder the jet closed, then drilled it out using a 0.0292" drill bit, which is no. 69 fine wire size... tiny little thing !

I don't even know where I could GET wire much smaller than that which wouldn't just kinda break off and get digested in the engine!

But I'd like to know how it works out for you when you get the chance to give it a try!

Good luck to you!
rc
 
I just did a 66cc last night with a v3 and had tosolder and drill the jet to a #76! I bet as the engine breaks in it will have to be enlarged. the engine pulls hard though, feels like a dirt bike! This engine is one of those lucky ones that has everything set up right from thefactory! The crazy thing is a 48cc i did a few weeks ago ran best with a jet size of #71, i think the timing may have been a little off though....
 
rustycase said:
No, ilikeabikea, I have NOT tried sticking a wire in a cns main jet.

but I DID solder the jet closed, then drilled it out using a 0.0292" drill bit, which is no. 69 fine wire size... tiny little thing !

I don't even know where I could GET wire much smaller than that which wouldn't just kinda break off and get digested in the engine!

But I'd like to know how it works out for you when you get the chance to give it a try!

Good luck to you!
rc
Click to expand...

Just to let everyone know, thin copper wires inserted into carb jets is a very common practice,especially in motorcycle racing.....
 
Has there been any more progress in this area?

I'm working with my own v3 carb at the moment. I have gone to a .68mm jet and it seems good on the top end.

Has anyone confirmed whether the v2 needle or NT needle will work and allow us to lean the mid throttle mixture?

I'm a little confused about the idle mixture screw. I have it all uncovered. I just don't know if I'm using it correctly. What's the word on how to adjust this one?

BTW, my engine is as listed in my signature. I am running without a head gasket, so my compression ratio is quite high. My engine seems to run best with the three prong plug that came with the kit. My mix is right around 24:1. I'm still breaking it in.

Lastly, does anyone have a picture of their throttle slide correctly set up? I would like to see if my idle speed screw is set close to correct.

One more thing :) When we talk about a float adjustment. What piece do we bend? What direction does what? And got any pics?
 
PAracer said:
I'm a little confused about the idle mixture screw. I have it all uncovered. I just don't know if I'm using it correctly. What's the word on how to adjust this one?

One more thing :) When we talk about a float adjustment. What piece do we bend? What direction does what? And got any pics?
Click to expand...

On the idle and mix screws... The idle screw just holds the slide open a little bit, so it is essentially doing the same thing as holding the throttle a little. No voodoo here in the adjustment, just set the idle speed screw to where your engine idles best. I set my idle really low cause my motor never stalls, if you have stalling issues you might tick the idle up a bit. (its a good idea to hold the throttle open a bit when turning the idle screw so you don't scar the slide, as the slide is sitting right on that screw when the throttle is released) As for the second screw, the air/mix adjustment (the one that was covered over), what I do is screw it all the way in and then back it out about 1 turn, then while the motor is idling adjust the mix screw to where your motor idles at the highest speed. Make small turns when doing this and give the motor a second to respond to the change.

On the float, don't have a picture, but in the middle of the metal part that supports the floats there is a little tab of metal, that tab pushes up on the needle valve. Picture the float in the carb, the needle valve is up ABOVE the tab, so if you bend the tab up the needle will close earlier and thus set a lower fuel level in the bowl. If you bend the tab down the float will close the needle later and allow more fuel into the bowl...
 
Thanks Nightcruiser!

i'm pretty good with the speed screw.
It's the mix screw that makes me a touch nervous. So it kinda works like the needle in the main jet. The more I back out the screw, the richer the mix. or is it an air bleed...

Am I correct in assuming that more fuel in the bowl makes the mixture richer across the board? Does it have other effects? Does it compensate for a slightly tilted carb?

sorry for all the questions. Thank you for all the answers.
 
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