That makes alot of sense, I think I will tear down the carb and give it a good clean. I'll report back, thanks for all of your help.
Jerky clutch
- Thread starter vincent713
- Start date
You seem very knowledgeable of these bikes, I wanted to ask you about the roller on the chain tensioner. One side should have the bolt go through while the other side should have a round cylinder bearing protector and then another flat washer on top of it correct? I've been tightening the nut and bolt on it and seems like the more I tighten the harder the roller turns. Is this something normal or am I doing something wrong?
On the tensioner, there are a couple minor variations on these units. Sounds like yours is similar to mine, round on the back side, the shaft is flattened a bit on the nut side of the roller to prevent it from turning when insterted in the slot on the bracket. These units have real bearings rather than just bushings, which is nice. After tightening a few times for adjustments etc the shaft on mine rounded out (the flat that fits in the slot that stops the shaft from turning) and made it almost impossible to tigten. (keeps turning like you describe)
The first thing I did was clamp the bolt in a vise and used a hacksaw to cut a slot in the end (where the nut threads on) deep enough to put a decent sized flathead screwdriver in there. This allowed me to tighten the nut that final turn by holding the bolt solid with a screwdriver.
Soon after that I realized the REAL source for all of my problems with the tensioner... The bushing they gave me is crap! It had deformed to an oval and was compressing, everytime I tighten it up after a ride and some torque it was a little loose again, cause the spacer was giving. So I went to the hardware store (with spacer and bolt in hand) and purchases a real brass bushing that had the right bore size, then cut it to length of the original bushing (filed smooth and level etc).
When I installed the tensioner with the new brass bushing I was surprised that it tightened up completely without having to use the screwdriver to lock the bolt. Since that day I never once had the tensioner come loose on me again.
I had only a small amount of slack I couldnt remove from my motor chain, so about 2 weeks ago when I had the motor pulled I made a spacer plate that moved my motor out to tighten the chain enough to run without the tensioner. I LOVE the bike without the tensioner, pedaling and coasting is almost liket he motor isn't there, I have much less noise and drag coming from the chain now. If you can manage it on your bike I suggest you give it a try.
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Also, let us know which type of carb you have on your bike so we can give you better advise on that. I think the root of your "jerky clutch" problem may just be a rough motor at low rpm...
I dont want to waste time giving advise until I know what carb you have...
I dont want to waste time giving advise until I know what carb you have...
Hi Nightcruiser,
Thanks for the advice on the tensioner, on my Giant mountain bike I took off some links from the chain to make it fit without using a tensioner. That seems to be working well but for this bike that I'm concern with, I bought it installed from a man who put the tensioner on it. I might have to just cut off some link and not use the tensioner like my Giant. The carb that I have is the stock NT, I have never clean it and thought I really don't need to yet since I'm running a fuel filter on it. It starts up fine, runs fine at higher speed but starts jerking at low speed. Also, it doesn't idle too well, it eventually will shut off if idle more than 2 min. I've adjusted the idle screw but it didn't really help. I really appreciate your help, I'm just like you, LOVE to cruise at night only.
Thanks for the advice on the tensioner, on my Giant mountain bike I took off some links from the chain to make it fit without using a tensioner. That seems to be working well but for this bike that I'm concern with, I bought it installed from a man who put the tensioner on it. I might have to just cut off some link and not use the tensioner like my Giant. The carb that I have is the stock NT, I have never clean it and thought I really don't need to yet since I'm running a fuel filter on it. It starts up fine, runs fine at higher speed but starts jerking at low speed. Also, it doesn't idle too well, it eventually will shut off if idle more than 2 min. I've adjusted the idle screw but it didn't really help. I really appreciate your help, I'm just like you, LOVE to cruise at night only.
Ok I finally got my gear puller part yesterday and here are the issues:
1. After cutting down the clutch studs and installing the new cover, it actually rubs the whole clutch itself with no clearance.
2. After pulling the small gear and small key, I installed the new clutch but now it’s hitting the crank pedal. Do I have to get new cranks now??
I got fed up and just reinstall my old parts back on. If I would have known it would be this much trouble, I would have not gotten this new clutch.
1. After cutting down the clutch studs and installing the new cover, it actually rubs the whole clutch itself with no clearance.
2. After pulling the small gear and small key, I installed the new clutch but now it’s hitting the crank pedal. Do I have to get new cranks now??
I got fed up and just reinstall my old parts back on. If I would have known it would be this much trouble, I would have not gotten this new clutch.
Honestly I think you are barking up the wrong tree with the centrifugal clutch, if the motor idles rough and runs rough at low RPM it wont matter if it has a regular clutch or centrifugal clutch, at slow speed it will be jerky when the motor is running rough. Once the clutch is engaged it is engaged, shouldn't matter if you have only the regular clutch or if you have the double clutch with the centrifugal operation.
I gather you are saying after you add the centrifugal clutch housing the crank hits the case? It would seem changing the cranks to a wider set would be the solution for this, I agree, what a pain in the butt...
I don't have the NT carb, I have the dreaded CNS carb and definitely have some tips to help make a CNS carb run smoother, but know nothing about the NT carb (other than they seem to be much easier to tune than the CNS)
Couple questions about this motor. Is it new or completely broke in already? What gas mix are you running? Have you cleaned the air filter? Checked for air leaks? If you have done all the above and with no results then perhaps you might want to try adjusting your float?
I gather you are saying after you add the centrifugal clutch housing the crank hits the case? It would seem changing the cranks to a wider set would be the solution for this, I agree, what a pain in the butt...
I don't have the NT carb, I have the dreaded CNS carb and definitely have some tips to help make a CNS carb run smoother, but know nothing about the NT carb (other than they seem to be much easier to tune than the CNS)
Couple questions about this motor. Is it new or completely broke in already? What gas mix are you running? Have you cleaned the air filter? Checked for air leaks? If you have done all the above and with no results then perhaps you might want to try adjusting your float?
This motor has been broken in approximately 3 months now. I'm running 32/1 ratio and have never cleaned the carb or air filter. As far as I know, there are no airleaks. When I get home today I will tear down the carb and give it a good clean. My NT carb is very basic but seems to be working very well. I've heard nightmares on the CNS.
Well, you don't break in a motor with time, you break in a motor with MILES, hard to tell how much you rode over 3 months? Was it at least 500 miles???
First thing I would do is clean the air filter, oily filter could create some troubles at low rpm that the motor can overcome as it revs higher....
Has the motor ever run smoother at low RPM, or has it always been rough?
I meant the motor has been broken in since 3 months ago. I hardly ever full throttle anyways. The motor has always been rough at low speed when I first got the bike.
Sorry to hear about your problems wit the CC.
If you have a steel crank, you can cold bend the ends to clear the housing, I would bend both sides so that they are even. I take the crank off and stick it into a vice and put a pipe on the end for leverage and bend them that way.
If the crank is aluminum, you would have to buy a wide crank kit.
Which cover is hitting? If the 'big cover' is hitting, then your manual clutch is sitting too high on the clutch shaft taper ( rare, I have only seen that once).
If the 'small' cover is hitting, then your centrifugal clutch is sitting too high on the crankshaft taper (more common).
In either case, remove the clutch and Dremel the hole to slightly increase its diameter, so that it can sit lower on the shaft. Go slow and constantly test fit the parts.
In one extreme case, the CC sat so high, I had the CC off and started the engine (it had a pull-start on it) and while the engine was running, I held a file to the spinning end of the crankshaft to thin it down a wee dab.
On the carb, I don't have the NT carb and haven't had one apart in front of me, so I can't give specific help, but....
If the carb has a main jet (large) and a pilot jet (small), pay special attention to the pilot jet when you clean the carb. My bike was running rough like you describe at one time, cleaned the carb, same deal. After fiddling with all sorts of stuff I pulled the carb apart (CNS) and removed the pilot jet. It is very tiny, only thing I could find to fit through it was the metal wire inside a cheap garbage bag tie (strip off paper, use bare wire). First poke through I could tell it was clogged up, the jet is so tiny it clogs easy and carb spray or compressed air might not be enough to clean it out (cause the hole is so small). After I cleaned my pilot jet the low end was so smooth and nice, it was like a miracle!
I'm not even sure the NT carb has a pilot jet, I know it is quite different from the CNS carb, but if you see a small jet and a larger jet, clean that smaller one good.....
You might also try searching the forum for threads about rough low end with the speed carb, or start a thread and ask other riders that have the same carb for advise.
If the carb has a main jet (large) and a pilot jet (small), pay special attention to the pilot jet when you clean the carb. My bike was running rough like you describe at one time, cleaned the carb, same deal. After fiddling with all sorts of stuff I pulled the carb apart (CNS) and removed the pilot jet. It is very tiny, only thing I could find to fit through it was the metal wire inside a cheap garbage bag tie (strip off paper, use bare wire). First poke through I could tell it was clogged up, the jet is so tiny it clogs easy and carb spray or compressed air might not be enough to clean it out (cause the hole is so small). After I cleaned my pilot jet the low end was so smooth and nice, it was like a miracle!
I'm not even sure the NT carb has a pilot jet, I know it is quite different from the CNS carb, but if you see a small jet and a larger jet, clean that smaller one good.....
You might also try searching the forum for threads about rough low end with the speed carb, or start a thread and ask other riders that have the same carb for advise.
This "is" the thread for rough low end speed, I thought it might be my clutch that is causing the rough ride. I'm about to clean my carb and report back, thanks for your help.
My crank is hitting the smaller cover, it looks like I have to bend at least 1 inch for clearance. The larger cover is hitting the old clutch from the inside, do I need to get more gasket for clearance? I appreciate you guys helping me.
What I am saying is, "THIS" thread is entitled "JERKY CLUTCH". Perhaps a new thread which title refers to "rough motor at low rpm with xx carb" might get you better help, since "jerky clutch" is likely not the problem. (or search the forum for tips to tune your carb to get smoother low end)
I know what you mean about a jerky ride at low speeds, I have been there, but I know my clutch had nothing to do with the problem. It was my carb, my whole motor was running rough unless it was rev'ing high. I had problems keeping consistent idle, it would die sometimes when I hit bumps, and low speeds were real rough. Like night and day, when I worked out my carb issue everything worked like magic. Starts in a snap, pulls smooth and solid from a very slow speed, idles great, all from cleaning 1 tiny jet....
I know what you mean about a jerky ride at low speeds, I have been there, but I know my clutch had nothing to do with the problem. It was my carb, my whole motor was running rough unless it was rev'ing high. I had problems keeping consistent idle, it would die sometimes when I hit bumps, and low speeds were real rough. Like night and day, when I worked out my carb issue everything worked like magic. Starts in a snap, pulls smooth and solid from a very slow speed, idles great, all from cleaning 1 tiny jet....
NT carbs only have 1 jet.
Here's a excellent thread that Norm did for us on the NT.
http://motorbicycling.com/f39/motorized-bicycle-carburetor-install-rebuild-302.html
Here's a excellent thread that Norm did for us on the NT.
http://motorbicycling.com/f39/motorized-bicycle-carburetor-install-rebuild-302.html
I've found in my own experience that this is caused by the teeth of the driven sprocket jamming up on the chain. You can solve it by getting a #41 or 415 chain and filing down the sprocket teeth ever so slightly.
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You could add more gaskets to increase the distance of the cover from the clutch. That is the easiest solution.My crank is hitting the smaller cover, it looks like I have to bend at least 1 inch for clearance. The larger cover is hitting the old clutch from the inside, do I need to get more gasket for clearance? I appreciate you guys helping me.
I personally would want to know why the old clutch is sitting so high up, and would try to get the clutch lowered onto the shaft.
I didn't tighten the clutch bolt that much but it seems like if I tighten more it will still hit the crank pedal. I put all of my original parts back together because I wanted to ride but I wanted to get all of the help I can get before I make another 2nd attempt on this new clutch. Your help is much appreciated.
This might be the problem of my "jerky" issue at low speed. I do notice the jerk is coming from the drive sprocket. I'm currently using a 415 chain, should I take out the small sprocket and file down the teeth?