new cms carbs ( of a 2011 66cc grubee)

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KANNONBALL13

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I have a new 66cc grubee and a CNS carb. The problem is the air/fuel screw is flat. I has no notch. I cannot use a screw driver to turn it. Am I missing something?
 
KANNONBALL13 said:
I have a new 66cc grubee and a CNS carb. The problem is the air/fuel screw is flat. I has no notch. I cannot use a screw driver to turn it. Am I missing something?
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Yes a NT carburetor. Not really sure but is it a plug due to EPA. Are you not sure that it isn't something that you can dig out exposing a slot?
 
If you don't have the cash to buy a replacement carb right away then I suggest you don't drill and pry it off. If you have a Dremil tool kit then that is your answer. Just cut a slit into the cap so it can be backed out with a flat-head screwdriver. Those caps are adjusted all the way in from the factory and need to be backed out manually for proper A/F ratio. Either way I have never been a fan of any CNS model and recommend you get a Dellorto or a RT clone.
 
Several people have posted that the cap covering the air mix screw comes off easy enough, and the air mix screw is underneath it. The cover is there to prevent you from accessing the screw, its not the screw itself....
 
I removed the cap by drilling a small hole in it......just going through it and then prying it off with an all or something pointy and sharp. There are no threads on the brass cover cap so if you cut a slot in it for a screwdriver, all you will be doing is turning the cap that has a shoulder on it. Once you get it off, turn the screw in against the seat and then back it out 1 1/4 turns. That will be a good starting point depending on elevation and temperature. I didn't have to make any additional slots in the brass metering pin for it to work either. Good luck but if you still get any bogging, you might have to increase the main jet....depends on which air cleaner you have on it as these things are real touchy with the fuel to air ratio. Thats what most people aren't understanding. I had one that bogged with the big air filter and as soon as I put the old style CNS air cleaner on it, the thing worked like a charm so I increased the jetting for the K&N style air cleaner and got even better results. But, like a few people have said in the post, if you don't have the time to tinker then the NT might be a better bet for you. Just won't get the throttle response that the CNS has.
 
I noticed the same thing about my CNS V2 Fonzie. It is sensitive to air flow, or more specifically the dampening provided by the air filter. If you change the air filter (or let it get clogged up) the mix will change and require some adjustment. Once you have the carb tuned to the filter you should be good to go unless you change the filter type or let it get all clogged up. But I guess that's true for just about any carb if you change around the filter...
 
Ok, here is my new issue and this is what I think is happening...
I was ridding and noticed a sudden spike in speed. It lasted about 30 sec. and then died. I was out of gas. so i filled up and the bike stared to loose power and speed. I turned the fuel off and after about 45 sec it spiked. I did this all the way home, just to get home.
I tried adjusting the air/fuel, and the trottle, but it seemed to run better with the air/fuel closed. I think I might be running to rich (rich in fuel low in air) I has ordered new smaller jets a few days ago, I think I will try them.

By the way, I tried taking the end off the muffler, and it sounded rad, but it was to loud.
 
KANNONBALL13 said:
I was ridding and noticed a sudden spike in speed. It lasted about 30 sec. and then died. I was out of gas. so i filled up and the bike stared to loose power and speed. I turned the fuel off and after about 45 sec it spiked.
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This is a good sign that you need to adjust the float so there is less fuel in the bowl. (The float needs to close the needle valve when it is lower in the bowl)
 
i would check fuel filters,and make sure bowl is clean.
the fuel tank may have a little dirt/water in it,running it outta gas can cause dirt issues.
 
I think you may be right on adjustin the tab on the float. ( bending it away from the float to shut off earlier) thanks for the reply.
I will look at sediment in the tank as well. I want to firts adjust the float tab,
then ride it, then adjust the needle, then ride, then jet it with a 70mm. and so on.
 
KANNONBALL13 said:
I think you may be right on adjustin the tab on the float. ( bending it away from the float to shut off earlier) thanks for the reply.
I will look at sediment in the tank as well. I want to firts adjust the float tab,
then ride it, then adjust the needle, then ride, then jet it with a 70mm. and so on.
Click to expand...

You got it, that is exactly what I would do. The fact that the motor comes to life shortly after the fuel is cut off is a dead giveaway that you need to do a float adjustment. Bending the tab up toward the needle is proper for this condition, just make sure you dont bent too much, it only takes a small change in the tab to make a big change in how the float sits.
It took me a couple tries to get the right setting on the float. Best thing to do is examine the position of the float as-is in both the up and down position, then compare that to how it sits after the adjustment. Don't make too radical of adjustment, you probably just need to change its position a little bit to get the fuel level where you want it....
 
While it is true that too high of a float level can cause a rich condition, it is most likely due to the jetting and not the float level. If the float is too high, fuel usually starts leaking from the carb. I suppose there may be a window where float is high enough to cause a rich condition without causing fuel to overflow, but it is most likely due to your jetting. When you are turning the fuel off, you are allowing the motor to get the proper amount of air/fuel mixture it needs for a second, then it runs out of fuel and you have to start the process over again.
 
its a good idea to make only one change at a time,then if it improves performance,you will know you are going in the right direction.
i have a bad habit,clean carb,adjust float,diddle twith the jet and idle setting.
what cured it?
 
I think i am on mark now! I adjusted the float and rejetted to .70mm, and it is running nice. Now I just need to get a 40 tooth, and find something else to break and fix!
BTW
I used a K&N filter cleaner on the air filter that got soaked in gas and it is superb now, I just want to find one that is "better". I was worried that after grad school I would not have anything to stimulate my mind, we I think I found something to hold me over until my PhD! Cheers to all you Blokes that helped me out! I will pass it on!
 
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