engine sputtering and dies below 10mph- won't idle

You can inspect the piston for contact damage by looking down the spark plug hole with a flash light. From what you are sharing, I do not suspect that you are having any issues with contact.
Excessive smoking can be caused by a rich air/fuel mixture or a heavy pre-mix to gas ratio.
32:1 is good for most pre-mixes. Some folks have outstanding results with using Opti II oil which is designed to mix at 100:1

If the business end of the spark plug is black you have a too rich fuel mixture.
If it is white, it is too lean. Chocolate to leather brown is an ideal color range. My spark plug is actually a grey-brown color due to the additives in the pre-mix oil I run.
 
You can inspect the piston for contact damage by looking down the spark plug hole with a flash light. From what you are sharing, I do not suspect that you are having any issues with contact.
Excessive smoking can be caused by a rich air/fuel mixture or a heavy pre-mix to gas ratio.
32:1 is good for most pre-mixes. Some folks have outstanding results with using Opti II oil which is designed to mix at 100:1

If the business end of the spark plug is black you have a too rich fuel mixture.
If it is white, it is too lean. Chocolate to leather brown is an ideal color range. My spark plug is actually a grey-brown color due to the additives in the pre-mix oil I run.

My fuel is actually 20:1 according to the spookytooth instructions.

When you check the spark plug each time do you clean it off for next time?

I actually have a new problem...

After the bike was running and idling well the other night I decided to cable-tie all the cables down and wire tape all the wires. I also had to open up the top of the carb to switch out the black rubber cap because I realized it came with a HD throttle I'm exchanging.

After that the bike was no longer idling, and when coming to a stop now it revvs full rpm without going anywhere. I noticed the ground wire had broken because I had it tightly smashed down in the engine mount. I connected another wire to it to lengthen it and taped it to the frame. Next ride same thing with revving when coming to a stop, and the kill switch wasn't working.

I also loosened the clutch cable a bit and then put it back to what I thought was the same tension.

My neighbor said that he thought it was a clutch problem (although he knows nothing about these bikes. He said that whenever you starve the engine or pinch the fuel line for example, an engine will rev up like that?

Could it be electrical? The clutch?

I'm going to take off the air filter and make sure the throttle needle is seating all the way, and the choke plug is seated all the way down too. Just to be clear... I think it was you or Al that said the remote choke actually is like an additional fuel way? So turning up the choke on the handle bar would actually be giving it more gas?

Any suggestion?

Thanks
 
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Electrical issues will not cause a high idle speed. There is no way a clutch can cause a high idle speed either.
A restriction in the fuel flow will cause an engine to rev higher due to the air/ fuel mixture getting too lean (too much air) just before the engine dies from lack of fuel. If this were the case you would not be able to ride the bike under engine power as the engine would not get enough fuel to run at higher engine speeds.
A tight bend in the throttle cable routing can though. It will not allow the inner wire to move freely inside the housing. Also, multiple bends in the routing can consume the overall working length of the inner wire also causing a high idle due to not letting the inner wire extend back out properly thusly holding the carburetor slide up too high. Usually there is enough adjustment in the cable end adjusters to compensate for this *if* the inner wire can still move freely.
The choke on your type of carburetor is an enrichment device. It opens up another port, sorta like an additional miniature carburetor, to allow a little more air and a whole lot more fuel into the intake charge.

Double check all of your wiring to be sure that there are no connections that have come undone or wires that got pinched through the insulation when you cable-tied everything.

It worked before, just carefully go backwards through all you have done until you find what has changed it's ability to operate. Assume nothing and check out every detail, even if you think the change had no affect. Something affected it!
 
aye. ze throttle cable be jamming... maybe :)

um...black rubber cap at top of carb? ehh?

make sure its sealing the cable entering into the top of the carb... make sure the top of carb is sealed full stop.

yeah. air sneaks in through there n gains access through the slide... leans out the mix, and is only noticeable on idle.... ratio of metered air to leaking air...

blocked choke jet thing... as geary says, an enrichment system. adds air and extra fuel. its why some bikes (motorcycles) idle high on choke. cus of the extra air.
but! if the jet administering the fuel for the choke is blocked... your adding air with little or no extra fuel, equals lean, equals revs really hi at idle...(with choke ON. no effect when its off. unless the choke plunger is leaking...)
 
Electrical issues will not cause a high idle speed. There is no way a clutch can cause a high idle speed either.
A restriction in the fuel flow will cause an engine to rev higher due to the air/ fuel mixture getting too lean (too much air) just before the engine dies from lack of fuel. If this were the case you would not be able to ride the bike under engine power as the engine would not get enough fuel to run at higher engine speeds.
A tight bend in the throttle cable routing can though. It will not allow the inner wire to move freely inside the housing. Also, multiple bends in the routing can consume the overall working length of the inner wire also causing a high idle due to not letting the inner wire extend back out properly thusly holding the carburetor slide up too high. Usually there is enough adjustment in the cable end adjusters to compensate for this *if* the inner wire can still move freely.
The choke on your type of carburetor is an enrichment device. It opens up another port, sorta like an additional miniature carburetor, to allow a little more air and a whole lot more fuel into the intake charge.

Double check all of your wiring to be sure that there are no connections that have come undone or wires that got pinched through the insulation when you cable-tied everything.

It worked before, just carefully go backwards through all you have done until you find what has changed it's ability to operate. Assume nothing and check out every detail, even if you think the change had no affect. Something affected it!

So I worked backwards and took some bends out of the throttle cable. I noticed that I wasn't hearing it 'hit' when I released the throttle. I adjusted loosened it to where I could here it hitting (bottoming out) again.

I did some reading and decided 20:1 was overkill and changed the fuel to 40:1.

I re-grounded to the engine and not the frame.

Noticed that there was a visual gap between the head and the 'body' of the engine. (where the head gasket is) Sorry for my ignorance when it comes to terminology. THey sent me an extra head gasket with my kit so I doubled up the gaskets and increased the torque from 13 to 17 with my less than accurate torque wrench.

Next ride goes well but doesn't quite idle. I figure it needs more fuel so I tighten the air/fuel screw and it idles. It's idling high so I unscrew the idle a few turns until it sound right. Run it again...perfect.

Then today I go out and run it and it's running pretty 'jerky'. I start to mess with the air/fuel and it smooths out the ride, but now it's not idling again. Turning in the air/fuel is getting it close but not quite. I figure I basically still have a low fuel/air ratio. Could be the float needs further adjusting but I decided to lower the needle clip one notch for the **** of it first. Run it again and it starts much smoother.

Seems I just can't get this carb tuned properly! I've read other threads where people had similar issues and just gave up on it completely and switched carbs.

Maybe the jerking today was due to the cold/rain/engine not warmed up yet, and I should have just left it alone?

I bent the tab up on the float quite a bit, so maybe it's a little too low now?

The carb didn't come with the threaded part that screws into the hole on top of the carb where the throttle cable goes in. It has one on the choke hole where the remote choke cable goes in, but not on the throttle hole. To remedy the extra slack in the cable I used that part from a caliper break where the cable goes in and you adjust the tension with the nut, but there are no threads in the throttle cable hole so it just basically sits in there and isn't tight. I'm wondering if air may be getting in through there and through the slide? If I take that piece out, I don't know if I can get enough slack out of the cable with the throttle adjustment alone. If I take it out, the end of the cable sits directly at the base of the hole. I hope that makes sense?
 
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