Got it running! Need help tuning

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geoldr

New Member
Jun 19, 2011
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California
Hey guys so today I finally got my bike running. Rode around the block a few times, and have some questions. I think my clutch isn't adjusted right. I drive a manual car, and my bike does the same thing as when theres not enough gas in first gear. The bike bucks, and giving throttle, doesn't do much. Sometimes it rides fine, but when I coast, it sometimes starts bucking. Also, I think it's too rich, because it sounds kinda boggy, and in neutral (cltch in) the bike will sometimes die. So what are my steps to diagnose and adjust and tune? I have a high performance plug wire, and the nh6bp (I think is what it's called) spark plug.
 

GearNut

Active Member
Aug 19, 2009
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San Diego, Kaliforgnia
Adjusting the clutch is easy:
http://motorbicycling.com/f4/clutch-cable-clutch-adjusting-procedures-22726.html

The carb I cannot comment on as I have no idea which one came with your particular kit.

The common carbs are NT, Speed, CNS, CNSv2.

NT and Speed are nearly identical, but the Speed had a larger throat.
The CNS and CNSv2 are very different. CNSv2 also has a cable operated choke mechanism. It's the only one that has that feature.

If you can identify yours, we can work out the tuning.
 

GearNut

Active Member
Aug 19, 2009
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San Diego, Kaliforgnia
If you are trying to run the engine at low RPM's then yes. Any bicycle speed slower than say 10 MPH and you have to squeeze in the clutch lever. Just like your car, it's not an automatic.
As for bucking at speed, Look for loose wiring between the engine and CDI or a loose spark plug wire first.
 

DuctTapedGoat

Active Member
Dec 20, 2010
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Nampa Idaho
When I had a bucking bike it ended up being the chain and sprocket, my alignment was off. So, I threw on my better sprocket (older style, not dished) and ouila - without a hitch, the bucking stopped at low speeds.
 

geoldr

New Member
Jun 19, 2011
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California
Ill examine the bucking issue tomorrow, I think it really might have just been I was going to slow. I was too excited that I got it to work that I didn't think about the speed. It might be the chain, theres a weird "clunking" sort of sound when its running. I don't even know how to explain it. not sure if its normal or not

What worries me more is that the bike sometimes dies while idling. Could this be that its running too rich?
 

GearNut

Active Member
Aug 19, 2009
5,104
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San Diego, Kaliforgnia
It could be too rich, but I highly doubt it unless the carburetor's float is set too high.

Every brand new carburetor needs to be tuned up and tinkered with.
I bet you just need to turn the idle speed screw in a little.
If you want to start from scratch, turn it all the way in until it bottoms out lighty.
Now turn it back out 3 1/2 turns. Fine tune the idle speed from that starting point. Turning it out is slower, in is faster.
 

DuctTapedGoat

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Dec 20, 2010
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It sounds like a clunk and shakes the bike violently in one big burst every couple seconds?

If that's it, then it's chain and sprocket issues.
 

geoldr

New Member
Jun 19, 2011
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California
It sounds like a clunk and shakes the bike violently in one big burst every couple seconds?

If that's it, then it's chain and sprocket issues.
Ill have to take a look at it tomorrow morning, but all i can tell you is that when riding the bike normally, with the clutch in, there is no sounds. but once the motor starts going, i start hearing some kind of clunk. maybe ill take a video of it tomorrow. If anything I figure it would be the chain and sprocket, I just don't know what else to do with it. Ive aligned it, and ive taken out as many links as possible in the chain, its not super tight, but its not lose. When looking at the chain tension pully, I can tell one side of it is much greasier then the other side. My sprocket teeth are facing outwards to avoid the chain hitting the tire.
 

DuctTapedGoat

Active Member
Dec 20, 2010
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Nampa Idaho
It also could be the teeth needing to be grinded back a bit. I'm just not a fan of those sprockets, I had two that did that, and didn't like it one bit. Another thing it did to me was that at only low speeds, once I got going it would stop.

If you can tomorrow, have someone take a close up vid of the chain and sprocket with you riding it.
 

geoldr

New Member
Jun 19, 2011
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California
After adjusting the clutch the noise went away, so that's good. After taking this video we realized how lose our chain looks. The problem is though, we can't tighten it anymore. If we tighten it just a little bit more, it wont fit on the bike. Do we need another tensioner pulley, or did we just do something wrong? Also, is it normal for that much smoke to come out of the muffler? The engine is brand new, and still doesnt even have 10 minutes of riding time on it, were worried to ride it because of that chain.

http://www.youtube.com/watch?v=4-jz8xmSEfM

Also!! This morning the bike wouldn't start. I had to replace the spark plug. I had the NGK NP6HS, and replaced with another and it works. Why would it just die in the middle of the night? I am really confused by that.
 
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geoldr

New Member
Jun 19, 2011
260
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0
California
So I can't shorten the chain anymore, because it won't fit on the bike. This is the only length of the chain that will fit. I can adjust the pulley, I am just not sure which way to adjust it. Move it forward / backward up/down etc.

The spark plug that wasn't working was black, and my bike has lots of smoke coming out of the muffler. Is that normal?
 

DuctTapedGoat

Active Member
Dec 20, 2010
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Nampa Idaho
I see it, the sparkplug even looks wet - you're running way too rich on fuel. You can lean the fuel out a bit by adjusting the throttle needle clip closer to the top.

Put the pulley closer into the chain, so the pulley would go when looking at it from the left of the bike to the top right. Don't go too tight though, you want about 3/4" of play.