Engine Locks When Clutch Lever Is Released

LBurdick43

New Member
Aug 10, 2016
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I'm not sure what the problem is here. When holding the clutch lever the chain spins freely as it should, but when I let it go to start the engine, it completely locks and I can't pedal or spin it at all. The engine is brand new, I've never started it. This is my first, so any help is appreciated.
 

2door

Moderator
Staff member
Sep 15, 2008
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How fast are you pedaling before releasing the clutch lever? You'll need to be traveling about 10mph or faster. Much slower than that and you might see the condition you describe.

If the clutch friction pads are stuck, not uncommon, there are several good posts and threads here on dealing with that. Try our 'Search' and type in "stuck clutch pads" to offer some suggestions.

Tom
 

LBurdick43

New Member
Aug 10, 2016
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Pennsylvania
I checked what you asuggested, but couldn't find exactly what I'm looking for. I removed the spark plug, but it doesn't help. Also, I realized that I can pedal with the clutch lever released, but it's extremely difficult. When holding the clutch lever down I can pedal just fine.
 

LBurdick43

New Member
Aug 10, 2016
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0
1
Pennsylvania
I took the clutch cover off on the side of the friction pads, and noticed that the glob of grease between the large and small gears hasn't moved, indicating that the engine hasn't rotated. Is something stripped internally because I can pedal without holding the clutch, but the engine internals aren't rotating?
 

LBurdick43

New Member
Aug 10, 2016
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Pennsylvania
It seems like my friction pads aren't gripping enough because the small gear that connects to the friction pad gear is completely stuck.
 
Last edited:

crassius

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Sep 30, 2012
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while it is open, take out spark plug and see if motor turns when clutch is engaged

if so, search here for cable/clutch adjust

if it does not turn with plug out, look for something stuck in gears or somewhere stopping it
 

ZipTie

Active Member
Jan 8, 2016
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Mpls Mn
Remove clutch side engine cover. Pull and lock your clutch lever in, then remove little lock screw on the flowere nut and remove the flower nut which should just spin off pretty easy even without a tool. Then gently pry off the bell cover off. Replace the bell cover and tighten the flower nut so the bell can rock back and forth. That alone may solve your problem.
 
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LBurdick43

New Member
Aug 10, 2016
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Pennsylvania
Nope, I've tried things such as that multiple times, my problem doesn't seem to be with the clutch, but with the small gear inside of the clutch friction pad casing being unable to turn at all. It's as if the engine is seized, but I've never run it because I can't.
 

LBurdick43

New Member
Aug 10, 2016
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1
Pennsylvania
It locks up and skids, I did it without the clutch cover to see if the small gear would turn, but it doesn't no matter what I try. If I keep pedaling with excessive force, the plate with the flower nut spins, but because the small gear is completely stuck, it just slides over the friction pads even though I've tried it with varying levels of tightness. Also just to clarify, my clutch is adjusted correctly and I can pedal and go freewheel with the clutch lever held down.
 

LBurdick43

New Member
Aug 10, 2016
19
0
1
Pennsylvania
I replied, but it looks like it didn't send. I'll try again, sorry if two of these appear. It locks up and skids because no matter what I do, I can't get that small gear to turn. When I pedal fast and then let go of the clutch and keep pedaling with excessive force, the plate with the flower nut keeps rotating, but because of the stuck small gear it just slides over the friction pads, even with a correctly adjusted clutch.

Edit: The first went on to a second page, it didn't disappear. I'm stupid.
 
Last edited:

MotorBicycleRacing

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Jul 28, 2010
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Removed magneto cover, tried to rotate the nut with the plug removed but it wouldn't budge. Turning left just unscrewed it, right went nowhere.
The only other thing to try would be pulling the 20 tooth gear to see
if that lets it rotate.
or
Your piston is being jammed by something, time to remove the head
to see what is going on.
Could be a foreign object in there, a broken ring, etc.
I have seen weld slag from the exhaust, nuts dropped in the cylinder.

You can also look in the exhaust port by removing the exhaust.
 

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
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Either something is jammed in the cylinder (like a broken piston ring), or the other thing that comes to mind is that maybe the engine was dropped & the case is damaged & hitting the flywheels?? (I had a customer do that to a new engine many years ago). :(
 

crassius

Well-Known Member
Sep 30, 2012
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first guess would be piston in backwards hanging a ring in a port

was motor together when you got it, or did you need to assemble the top end?

either way, it needs to be opened or sent back
 

LBurdick43

New Member
Aug 10, 2016
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Pennsylvania
It was together when I bought it. I took the top end off today, and nothing seems to be wrong with the piston, and there weren't any foreign objects in the shaft. The piston itself can move around a little, but not up and down. I'll look more into it when I get home later. How could I tell if the piston's backwards?
 

crassius

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Sep 30, 2012
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the pins that hold the ends of the rings in place must be at same side as the carb

if you have cylinder off & it won't turn something other than piston is holding crankshaft
 

MotorBicycleRacing

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Jul 28, 2010
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It was together when I bought it. I took the top end off today, and nothing seems to be wrong with the piston, and there weren't any foreign objects in the shaft. The piston itself can move around a little, but not up and down. I'll look more into it when I get home later. How could I tell if the piston's backwards?
Ignore the advice about the piston being backwards as that is not
why the piston is not rotating.
The ring pins and ends face the intake on a correctly installed piston.
An arrow will point to the exhaust or a triangle will point to the intake.

It would help if you posted a few pics.

you say top end but I presume you mean the head?
next try to remove the cylinder body to check if the rings are
broken and to see if,
one or more of the 4 studs may have been overtightened and
cracked the case which will stop the crank from turning.