brand new 80cc pk80 kit just acts like a brake when clutch released

jacobstechandbikes

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Joined
Aug 30, 2018
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10
I had this same exact issue happen about 6 months ago on a 280 dollar engine, which really annoyed me. But I knew their return policy, I got over it. It’s been great for parts anyway...

I’ve bought another one from a different site, a nicer pk80 one, CHEAPER too. I took off my 49cc kit I got from eBay for 80 bucks over a year ago, which surprisingly is the cheapest kit I’ve bought, and has been the most reliable, only needed a new magneto last week after I shorted it out.


I assembled the top end of the new engine, with the upgraded pk80 cranks, and I hooked up the clutch. It came with a motor mounted chain tensioner, which rubbed on my current bikes tire, so I used one from my old kit, that mounted on the frame. But after getting everything mounted up, and hooked up well, the same thing happened this year that happened with the last 80cc kit! I’ve never had this issue with a 49cc kit. When I go to pedal then release the clutch, it feels like I’m pedaling over sticky tar, and it just shows down. I don’t hear the piston going up and down, but it is, when I lift it up and turn the wheel by hand, it takes about a full two turns to hear air release from the exhaust. I know my chain was too tight, but it was getting dark out. I adjusted the clutch too, which changed nothing. I’m gonna try to loosen the chain tension up a bit tomorrow, but idk if that will fix it, any ideas would be appreciated. Thanks!
 


Lukesky36

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Oct 3, 2018
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316
ok there are a few things you can do first take the plug out and squirt some oil in there put the plug back in put your elbow on the seat and lean on the bike untill the engine turns over try to lube the bottom end and top end with some straight oil and see if that helps just keep turning it over untill the bearings and the rings are all lubed up
 

jacobstechandbikes

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Aug 30, 2018
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ok there are a few things you can do first take the plug out and squirt some oil in there put the plug back in put your elbow on the seat and lean on the bike untill the engine turns over try to lube the bottom end and top end with some straight oil and see if that helps just keep turning it over untill the bearings and the rings are all lubed up
I oiled up the cylinder walls and seals and everything when I assembled the top end, I think it has to do with the clutch, but I’m not sure.
 

mark20

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Sep 26, 2018
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311
I oiled up the cylinder walls and seals and everything when I assembled the top end, I think it has to do with the clutch, but I’m not sure.
my bike used to do that as well.
your clutch arm dosent have enough movement for the clutch to engage fully.
try to loosen the cable so you can freely move the arm (it should have a bit of play) when you pull the lever, the clutch should fully disengage when the lever is 3/4 to nearly all of the way pressed in.
 

Tyler6357

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Sep 28, 2011
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526
Here is a deciphering of how to properly adjust your clutch cable and clutch flower nut.
Always adjust the cable before adjusting the flower nut.

How to adjust cable:
1. Loosen the lock screw in the brass cable end until the cable can slide through it. Do not remove the brass cable end from the cable.
2. While keeping the brass cable end in the cable hole on the tip of the clutch release arm , grab a hold of the end of the cable with pliers and pull the cable through the brass cable end until the cable is tight.
3. Swing the release arm (with the brass cable end still in the tip of it) inwards towards the carburetor until it stops swinging. Do not forget to keep pulling the cable through the brass cable end as you are doing this.
4. While holding the cable relatively tight and keeping the brass cable end in hole at the tip of the release arm, and the release arm rotated fully towards the carburetor, tighten the lock screw in the brass end.
The cable strand between the cable housing stop thing on the top of the engine case and the release arm should almost be in a straight line now.
You should barely be able to wiggle it. It should not be as tight as a piano wire though.
About 1/32" freeplay.


Adjusting the clutch:
1. Adjust clutch cable as described above so there is only a little bit of slack, about 1/32", in the inner wire when the hand lever is released all the way out.
2. Remove gear case cover from right side of engine.
3. Remove lock screw from clutch outer plate. It's the little screw that fits into the notches on the edge of the center nut (called a flower nut).
4. Squeeze in clutch hand lever until it touches the hand grip. Hold it in with the lock button or some tape or a piece of wire, zip-ty, ect.
5. While pushing in on the outer clutch plate with one hand, tighten the flower nut until snug, just using your fingertips. Do not use pliers, ect.
6. Unscrew flower nut 1/2 (180 degrees) to 1 full turn (360 degrees) out, aligning a notch on the flower nut with the hole in the outer clutch plate that the lock screw goes into.
7. Install lock screw but don't tighten it just yet.
8. Remove tape or wire from hand lever and let it release all the way out.
9. Tighten lock screw for flower nut.
10. Adjust clutch cable if necessary to give just a little free play to the inner cable when the hand lever is all the way out. You should be able to wiggle the clutch release arm a little.
11. Install gear case cover and test ride. Every clutch is a little different.
You may have to fine tune the adjustment of the flower nut by a few notches.
 
Joined
Apr 6, 2017
Messages
64
my bike used to do that as well.
your clutch arm dosent have enough movement for the clutch to engage fully.
try to loosen the cable so you can freely move the arm (it should have a bit of play) when you pull the lever, the clutch should fully disengage when the lever is 3/4 to nearly all of the way pressed in.
I purchased a runwell pk80 from bicycle motor works and had similar issue's mine was corrected by adjusting the clutch pressure plate and turning the spring tension down on the clutch.
I believe the reason these engines are so inexpensive (cheap)Is that they are not fully or properly set up time and patience is the remedy nobody should have to buy an engine and have to use it for parts p.s. do the clutch spring tension as a last resort as it will alter your entire clutch set up
 

jacobstechandbikes

New Member
Joined
Aug 30, 2018
Messages
10
I purchased a runwell pk80 from bicycle motor works and had similar issue's mine was corrected by adjusting the clutch pressure plate and turning the spring tension down on the clutch.
I believe the reason these engines are so inexpensive (cheap)Is that they are not fully or properly set up time and patience is the remedy nobody should have to buy an engine and have to use it for parts p.s. do the clutch spring tension as a last resort as it will alter your entire clutch set up
Wow, I guess it’s pretty common. I bought the exact same runwell pk80 from bicyclemotorworks as well! The support team was very helpful in providing me the link to the video I posted above, which helped! Apparently, it’s not the fault of bicyclemotorworks, the support guy told me in the factory they tighten them all, and sometimes incorrectly.
 
Joined
Apr 6, 2017
Messages
64
Wow, I guess it’s pretty common. I bought the exact same runwell pk80 from bicyclemotorworks as well! The support team was very helpful in providing me the link to the video I posted above, which helped! Apparently, it’s not the fault of bicyclemotorworks, the support guy told me in the factory they tighten them all, and sometimes incorrectly.
Other than that it seems to be a decent running engine
 
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