Frame mount Huasheng 4 stroke, no acceleration

NeoEleganceDesign

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Hey guys,

A few months ago I picked up a frame mount 4 stroke kit from bicycle-engines.com and have been piddling around putting it together. I finally got it all together about a week ago. At first I had a few issues with the chain popping off, but I think I set the chain tension correctly today. I can get it to start and idle just fine. However, when I engage the clutch and give it gas, nothing happens.

The motor revs up and I can see the clutch lever engage, but there isn't any power going to the rear wheel (even at full throttle with the choke off). I know these motors aren't extremely powerful, but I'm pretty sure I should feel at least some forward motion while sitting on the bike while it's stopped. I only weigh 140 lbs, so I highly doubt my weight is an issue. The same thing happens standing next to the bike with the clutch engaged and full throttle. I opened up the gearbox (Grubee Skyhawk II, I think) and everything looks okay.

What could be the problem?
 
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Any chance you left out the key that engages the clutch to the output shaft of the motor?

ocscully
 

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The key from the output shaft of the motor is there. I took the cover off the gearbox, removed the two secondary gears and started the motor and the gear that is connected to the output shaft of the motor spun just as fast as the motor and the key and keyway for the output shaft of the gearbox seems fine.

I included a couple of photos this time.
- The first is the gearbox with the cover removed.
- The second is the gearbox output shaft with the clutch disengaged.
- The third is the gearbox output shaft with the clutch engaged.
- The last two are pictures of the bike itself from both sides.
 

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Since the key is installed, then it pretty much has to be the engager mechanism. Is there any slack in the cable and housing that operates the engager? Maybe you aren't getting full engagement when the lever is pulled in? Remove the chain from the output sprocket of the gearbox and then operate the engager by hand with the motor running to see if the output sprocket turns. If you could take a photo of the cable attachment to the engager perhaps more could be determined?

ocscully
 
Well, I removed the chain and the output sprocket spun when I engaged the motor. I figured that maybe I tightened the chain too much so I added a couple of links back and loosened the tension wheel and still no power to the rear tire. Here' the photos of the engager with the lever pulled in and released. With the current tension at the grip, the lever only needs to be pulled in half way to pull the engager all the way.
 

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I'm stumped at this point, but I do notice that the configuration of your intermediate gear is different than shown at both the GRUBEE and bicycle-engines.com web site. See photo below and compare with the one you have. Why does the smaller gear go all the way thru the larger one? It very well may not be the problem and is just a design change the came after the photos from the factory were taken. But if both gears aren't keyed to the intermediate shaft it could be the problem? The other thing I notice is that I don't see that you have cable housing all the way to the barrel adjuster for the engager? It could just be the angle of the photo though.

Hopefully Houghmade and some of the other members with these kits will have some ideas?

ocscully
 

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Based on what you said about the keys being good and in place and the picture above, it looks to me like the engager lever is not engaging all the way when you pull the handle (an assanine design, by the way). With the engine off and the rear wheel in the air so it can spin, push the engager lever as far as it will go towards the way it engages, the spin the rear wheel forward- you should be able to feel a distinct difference between engaged and not engaged. With your hand on the engager lever, you will probably feel it engaging. When mine is engaged (which is all the time), the lever looks to be further back than yours. Here is a picture- you will note I reversed the engager so it is engaged all the time except when I pull the handle.

Irish John has this setup too and knows more about this gearbox than just about anyone; maybe he will chime in with his thoughts.
 

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Centrifical Clutch on Backwards ?

I am thinking that you may have put the clutch on the motor backwards (with the side that you can see the springs from facing out)

I am also guessing the clutch segments will be thrown out, but not really wedge against the bell housing. Thus no real power to the output.

Worth a check?

Jim
 
This GB has a lot of keys. Did you check the key for the engager and the key for the 11T sprocket? One way to isolate the problem would be to remove the cover to expose the gears and remove the chain so that you can spin the GB sprocket by hand while observing the gears. Try holding the main gear stationary with one hand while spinning the sprocket with the other hand. If you are able to spin the sprocket without the main gear spinning, then it sounds like a key is missing or broken for either the engager or the sprocket. Make sure that the engager is set to transmit power from the GB to the sprocket before doing this check.


66
 
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