Centrifugal clutch problem, Help!

Losíf

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Feb 12, 2017
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So I just put together this 49cc 4stroke 7g t-belt engine onto my bike. It runs and all but a major issue is present guessing it's the centrificul clutch staying engaged. I can pedal the bike to start the engine like a 2stroke bike while not holding the manual clutch in. If I start the engine without sitting on it'll drive away. The wheel does not move freely, and I think it all comes down to the centrificul clutch. I think I might have installed it wrong but it doesn't seem like I did. Does anyone have a fix to this?
 


KCvale

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So I just put together this 49cc 4stroke 7g t-belt engine onto my bike.

It runs and all but a major issue is present guessing it's the centrificul clutch staying engaged.
I can pedal the bike to start the engine like a 2stroke bike while not holding the manual clutch in.
The cent clutch is not installed correctly, the bike should roll free with the engine off.
 

Losíf

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Feb 12, 2017
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The cent clutch is not installed correctly, the bike should roll free with the engine off.
Yes, I'm pretty sure the centrificul clutch is at fault, should I just take it out and reinstall it using more caution?
 

gary55

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Nov 27, 2012
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I believe yours has the straight shaft with a bushing rather than a bearing. Sometimes these bushings seize to the shaft, and require lubrication. When you dis-assemble it look at the bushing for signs of scoring. Somewhere in these forums I have read some bushings require soaking in a lube for a period of time to reduce seizing.
 

Losíf

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Feb 12, 2017
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I believe yours has the straight shaft with a bushing rather than a bearing. Sometimes these bushings seize to the shaft, and require lubrication. When you dis-assemble it look at the bushing for signs of scoring. Somewhere in these forums I have read some bushings require soaking in a lube for a period of time to reduce seizing.
Yes, I noticed it was stuck rather than freely spinning in the clutch. It was kind of hard to remove it (I used a flathead and a hammer to give you an idea of how stuck it was). I did put lubrication on it (3 in 1 oil) before putting it on. You mention soaking it for period of time; How long would that be and why? Thanks.
 

gary55

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Yes, I noticed it was stuck rather than freely spinning in the clutch. It was kind of hard to remove it (I used a flathead and a hammer to give you an idea of how stuck it was). I did put lubrication on it (3 in 1 oil) before putting it on. You mention soaking it for period of time; How long would that be and why? Thanks.
I am hoping some of these other guys will pipe in on this. I use the 4g. It has bearings so this problem doesn't happen.

All the attempts I have made on other peoples bikes to solve this problem have been short lived so my experience is lacking at best. I would take some very fine emery cloth to clean up any gouges and lightly coat it with a lube that has high heat resistance, and may be a teflon additive in it.
As to the soaking, that is something I read somewhere. It could have applied to a different type bushing.
I know, not much help there. Still your on the right track so first You should give this thread a little time so some of the others here with a more educated experience of this prob. can help you further. Best of luck.
 

gary55

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If you don't get any more info here google service tips for gokarts and minibikes. They have a section covering cent. clutch and bushing lub.
 

Losíf

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Feb 12, 2017
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I am hoping some of these other guys will pipe in on this. I use the 4g. It has bearings so this problem doesn't happen.

All the attempts I have made on other peoples bikes to solve this problem have been short lived so my experience is lacking at best. I would take some very fine emery cloth to clean up any gouges and lightly coat it with a lube that has high heat resistance, and may be a teflon additive in it.
As to the soaking, that is something I read somewhere. It could have applied to a different type bushing.
I know, not much help there. Still your on the right track so first You should give this thread a little time so some of the others here with a more educated experience of this prob. can help you further. Best of luck.
Thanks so much for the info, I'll give this more time and hopefully someone will give some answer.
 

KCvale

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Ya, I can help, it would just help more if people would just stop buying discounted sh*t that is discounted because it's sh*t from the likes of gasbike and bikeberry.

Your mistake was buying a 4-stroke engine with a long straight shaft and no clutch already on it. The best would be the 49-53cc HS -1G engines with a short shaft with a clutch attached, you can use 4G transfer case on that.

Your delima is how to get a bushing to spin free on the moving engine shaft without bearings while under under belt/chain tension on it.

That bronze bushing your clutch bell ride on is called an Oilite Bushing, soak it in 30W oil overnight, it's the only lube it going to get.

Only adjust it (if you even can) to semi a tight belt, get it too tight and it's a constant angular drag on the bushing.

Don't bother with trying to replace the bushing with bearings, been there done that and it was an expensive fail.



All I can suggest is you soak that bushing, and then pack it with grease when you put it in, and of course, get the right engine next time so you can use the trouble free 4G transfer case ;}

Note, anyone dealing with a big HF or Honda engine is faced with this as well, so it can be done well enough, but if you just want just a reliable small 4-stroke, go with the HS 142F-1G and 4G combo, it sure has worked great for me.
 
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gary55

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After looking into this a bit more I see the trying to clean up the surface through grinding is not recommended due to smearing the pours of the material that hold the oil. Heating the oil " 30 wt." to between 80 and 100 deg. c- 176 to 212 deg. f will cut the soak time to 20 min., or put under vacuum and wait for it to stop bubbling.
I think if the bushing looks badly scored I would just replace it. Another thing you might want to consider with this type of drive is having two bushings. One could always be soaking and ready for a swap out at the first signs of seizing. After a while you will get a sense of the interval and catch it before seizing starts. It may become less frequent once the clutch breaks in. Less slipping less heat.
 
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