This is Duchess. A beautiful silver blue Micargi-Rover beach cruiser, with a silver Grubee SkyHawk 80. It's only a few hours old now, and has been around the block for about 3 miles so far. It belongs to my friend Corinne.
http://www.youtube.com/watch?v=dXysa1FNzEs
When I fired this beautiful bike up for the first time, a few hours ago, it started easily enough with full choke. After a little warm up, what I noticed was a total lack of power above about a 1/4 throttle. All it will do is bog if you give it any throttle. It can barely get up to 10 mph. After a little screw turning I was at least able to get it to idle pretty good, so I don't think it's leaking air.
That's the total extent of the tuning I've done so far. This carb has a aftermarket air cleaner, but the red plastic one is what came on it.
I've been reading about the typical problems people are having with the CNS carb for months, but this is the first time I've had one in hand. I won't toss it in the trash until it's running good lol.
Based on the comments I've read about this carb, I have to agree. Everyone pretty much nailed the description of the symptoms. What I want to know now is what to do next. Some people claim they've made it work, but the how seems a little vague.
Edit//After a few more weeks time, and tuning experience by myself, and fellow forum menbers tuning this carb, this is what we came up with.
How to tune the CNS V2 Carb.
_________________________________________________________________________________
Before even starting, it's highly recommended you toss your stock spark plug, and install a
NGK B6HS, or BP6HS. Both of these plugs are proven beyond a doubt to be dependable, and run well. Doesn't seem to matter whether you have a 50, or 80cc. About $2.50 each
1: Raise the float level.
Turn the Carb upside down. There's a seam in roughly the center of the plastic float. Adjust the float till the seam in the middle is parallel to the sealing surface of the float bowl.
2: Top end adjustment is as follows. Drill out the main jet. Check the color of the plug to help you decide tuning. Black is RICH, White is LEAN
Buy Machinist bits #64 #65 #66 #67 #68 #69 #70 (Stock jet size is #70)
Drill out the jet one dril size at a time starting with smallest, #69. Test and check for full throttle response and spark plug color. Below 1000ft altitude #65 and #64 seem pretty close. This can vary depending on the state of tune, but if you're reading this your engine probably isn't too exotic. If you drill too large of a hole, and want to go leaner, fill the jet with solder, and re-drill with a smaller drill bit.
3: Low and mid range, adjust the C-Clip on the carb needle.
(Top is lean and bottom is rich) Check your spark plug for direction.
For me, the correct position has always been obvious after a couple trys.
4: Idle adjustment.
The Idle mixture, and idle speed adjustment screws are on the right side of the CNS V2 Carb. The adjustment screw closest to the air filter is the idle mixture screw. The adjuster screw more toward the middle of the carb is the idle speed adjustment.
Basicly you just turn the idle speed adjuster screw in far enough to hold the slide up high enough to hold an idle. As you screw the adjuster in it's a good idea to open the throttle a little so the adjuster doesn't goudge the side of the slide. Now that it's idling, try turning the idle mixture screw both directions to find the fastest idle. Now go back to the idle speed adjuster, and adjust as needed.
Foot note: In some cases, but not all, removing the breather tube from the air filter may result in better performance.
http://www.youtube.com/watch?v=dXysa1FNzEs
When I fired this beautiful bike up for the first time, a few hours ago, it started easily enough with full choke. After a little warm up, what I noticed was a total lack of power above about a 1/4 throttle. All it will do is bog if you give it any throttle. It can barely get up to 10 mph. After a little screw turning I was at least able to get it to idle pretty good, so I don't think it's leaking air.
That's the total extent of the tuning I've done so far. This carb has a aftermarket air cleaner, but the red plastic one is what came on it.
I've been reading about the typical problems people are having with the CNS carb for months, but this is the first time I've had one in hand. I won't toss it in the trash until it's running good lol.
Based on the comments I've read about this carb, I have to agree. Everyone pretty much nailed the description of the symptoms. What I want to know now is what to do next. Some people claim they've made it work, but the how seems a little vague.
Edit//After a few more weeks time, and tuning experience by myself, and fellow forum menbers tuning this carb, this is what we came up with.
How to tune the CNS V2 Carb.
_________________________________________________________________________________
Before even starting, it's highly recommended you toss your stock spark plug, and install a
NGK B6HS, or BP6HS. Both of these plugs are proven beyond a doubt to be dependable, and run well. Doesn't seem to matter whether you have a 50, or 80cc. About $2.50 each
1: Raise the float level.
Turn the Carb upside down. There's a seam in roughly the center of the plastic float. Adjust the float till the seam in the middle is parallel to the sealing surface of the float bowl.
2: Top end adjustment is as follows. Drill out the main jet. Check the color of the plug to help you decide tuning. Black is RICH, White is LEAN
Buy Machinist bits #64 #65 #66 #67 #68 #69 #70 (Stock jet size is #70)
Drill out the jet one dril size at a time starting with smallest, #69. Test and check for full throttle response and spark plug color. Below 1000ft altitude #65 and #64 seem pretty close. This can vary depending on the state of tune, but if you're reading this your engine probably isn't too exotic. If you drill too large of a hole, and want to go leaner, fill the jet with solder, and re-drill with a smaller drill bit.
3: Low and mid range, adjust the C-Clip on the carb needle.
(Top is lean and bottom is rich) Check your spark plug for direction.
For me, the correct position has always been obvious after a couple trys.
4: Idle adjustment.
The Idle mixture, and idle speed adjustment screws are on the right side of the CNS V2 Carb. The adjustment screw closest to the air filter is the idle mixture screw. The adjuster screw more toward the middle of the carb is the idle speed adjustment.
Basicly you just turn the idle speed adjuster screw in far enough to hold the slide up high enough to hold an idle. As you screw the adjuster in it's a good idea to open the throttle a little so the adjuster doesn't goudge the side of the slide. Now that it's idling, try turning the idle mixture screw both directions to find the fastest idle. Now go back to the idle speed adjuster, and adjust as needed.
Foot note: In some cases, but not all, removing the breather tube from the air filter may result in better performance.
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