1 week riding and there is a clutch/transmission problem.

ButterBone

New Member
Joined
Mar 12, 2019
Messages
2
I bought a second hand gas bike it for my son to commute to work on.
He's been using it about a week and today it developed an issue.
This is pretty much the kit and by pretty much, I mean everything listed in this kit is exactly what is on his bike.

huashengtaishan 4 stroke kit
HuaSheng 49cc with Centrifugal Clutch Engine (4-Stroke)
Chain Drive Centrifugal Clutch Transmission with 10 Tooth Sprocket
2.5 L Gas Tank
Gasoline Tank Switch (AL)
Fuel Line #2
Fuel Filter
Improved Wide Pedal Crank
44 Tooth Sprocket
Pineapple Bushing
Accelerograph Throttle Handle
Throttle Cable 50"
Mounting Plate
415 Heavy Duty Chain
Idler Pulley Chain Tensioner
Chain Guard

-------------------------------------------------------------------------------------------------------

Symptoms:
When started the bike now wants to surge forward.
:: When we first got it we could start it, and it would stand still as long as there was no throttle applied. If you picked up the back of the bike by the cargo rack the wheel didn't start spinning.

Today when I was looking at it when the motor was running I would lift the back by the cargo rack and the wheel would start spinning instantly and accelerate and you could hear the engine pitch up in acceleration.

When he was riding it everything was ok as he rode it up a hill. Not a terrible hill, about 12%grade for 1/4 mile. He said there was no problem coming up the hill, but when he got to the top it bogged down and then died. He stopped it, started started the engine and started riding and after 50 feet it bogged down again and died.

When I was looking at it and held up the back and throttled it, it seemed to run fine all the way open. I thought he was trying to baby the throttle, like the first day (which caused it to sputter and stall) but just when I was convinced he was just causing it to stall with not enough throttle it bogged down at full throttle and the clutch/transmission sounded clanky, but not grindy, and then it bogged out completely and stopped.

----------------------
He's only put about 8 hours on it since we got it. I've made sure he put premium fuel in it. It got a new fuel filter and oil change the day we bought it. I watched the seller change the oil and add a new fuel filter. Nice man.

I'm pretty handy. I work on my own cars and motorcycles and lawnmowers, but I've never dealt with Centrifugal Clutch Transmission before.

What can I test - and how - to help diagnose the problem correctly. Once I know what's wrong, I'm sure I can fix it or replace it. I just don't know where to start diagnosing it.

Thanks
 


Lukesky36

Active Member
Joined
Oct 3, 2018
Messages
432
it could be a very lean fuel air ratio condition that is keeping the rpm really high and bogging your motor out and it dieing out from overheating and trying to run away from you when you start it richen the needle adjustment
 
Last edited:

The_Aleman

Well-Known Member
Joined
May 2, 2007
Messages
948
Sounds like the clutch got cooked. Can you take a picture of the transmission? If it's the transmission I think you have, it's tall-geared and not made for hills with a 44T sprocket. You can get a good replacement clutch from Staton-Inc.

Premium gasoline is unnecessary, 87 is overkill. The engine has under 8:1 compression, it will never need premium.
 

ButterBone

New Member
Joined
Mar 12, 2019
Messages
2
Hey Guys,

Thanks for the responses. It was "a bit-o-both".. 2 weeks ago when we bought it, the weather was bitterly cold and the seller has increased the throttle so it would start easier. When I turned down the carb throttle it settled down and ran smooth, but really...it was the clutch.
When I took the transmission off one of the clutch springs had shattered and the clutch pads themselves were worn almost entirely down. The shattered spring was popping in and out from behind the rest of the clutch assembly so that was the clang I was hearing.
I'm more impressed with this little set up every day.
86365

The clutch looks just like this. Though on amazon it doesn't give a "size" but its the first thing that came up when I searched "huashengtaishan 4 stroke clutch parts".
I figure that is a pretty good sign.
Are there other sizes of this? If I find a manual for the kit online would it tell me the size I need? Amazon lists this one as
Flying Horse 49cc 4-Stroke Motorized Bicycle Engine Clutch Flyweight – Gas Bike Clutch Replacement
$20.49
There are also Woostar and Wingsmoto for less.

Any advice would be greatly appreciated.

Bad news is one of the bolts on the transmission sheared off when I went to loosen it. Luckily there is more than a quarter inch sticking out so I may be able to cross drill it and twist it out. Worst case I have to drill it out.

Thanks again.
 

bakaneko

Well-Known Member
Joined
Nov 16, 2015
Messages
1,290
1. The transmission mounting bolts and inner threads are extremely weak. You need to hand tight this; not arm leverage.

2. I researched this system a lot and am almost 100% sure that this is what is happening. The clutch drum diameter is way too big for the 3 arm clutch. This clutch is the same as used in the pocket bike. BUT, the pocket bike clutch bell diameter is like .200 less than the HS-142F. So, with the 3 arm clutch will engage the HS-142F clutch at a higher RPM and hence the heat, which is popping your springs. This is a no win situation; you will go crazy trying to replace the clutch or the springs over and over again.

SOLUTION
  1. Hand tighten these or try not to mess with it at all.
  2. Two ways. #1 - Change the HS-142F clutch bell with the pocket bike one. I did this one cuz I had a spare pocket bike bell. I had no spring pops in 1000+ miles when I know it should have popped by then. And, I also used the pocket bike version of the clutch which has really questionable metallurgy and no failures. #2 - I like this way better is to buy a Staton premium clutch that has a larger retracted diameter than the 3-arm clutch and heavy duty springs. Most guys here do that.
http://www.staton-inc.com/store/index.php?p=product&id=1676

Yes, it is $48. But, you cannot avoid one of these solutions or you will live in fear and not fully use your engine to avoid spring pops. I only did the bell change because I had a pocket bike bell available. Also, its a b*tch to replace the bell.
 

bakaneko

Well-Known Member
Joined
Nov 16, 2015
Messages
1,290
Also, when you say chain drive transmission do you mean the hoot transmission with one chain drive inside the reduction gear box. If so, you will need to do something with this also to avoid going crazy. Let me know if it is it and I can tell you solutions or a better transmission.
 
L

L. s.

Guest
I bought a second hand gas bike it for my son to commute to work on.
He's been using it about a week and today it developed an issue.
This is pretty much the kit and by pretty much, I mean everything listed in this kit is exactly what is on his bike.

huashengtaishan 4 stroke kit
HuaSheng 49cc with Centrifugal Clutch Engine (4-Stroke)
Chain Drive Centrifugal Clutch Transmission with 10 Tooth Sprocket
2.5 L Gas Tank
Gasoline Tank Switch (AL)
Fuel Line #2
Fuel Filter
Improved Wide Pedal Crank
44 Tooth Sprocket
Pineapple Bushing
Accelerograph Throttle Handle
Throttle Cable 50"
Mounting Plate
415 Heavy Duty Chain
Idler Pulley Chain Tensioner
Chain Guard

-------------------------------------------------------------------------------------------------------

Symptoms:
When started the bike now wants to surge forward.
:: When we first got it we could start it, and it would stand still as long as there was no throttle applied. If you picked up the back of the bike by the cargo rack the wheel didn't start spinning.

Today when I was looking at it when the motor was running I would lift the back by the cargo rack and the wheel would start spinning instantly and accelerate and you could hear the engine pitch up in acceleration.

When he was riding it everything was ok as he rode it up a hill. Not a terrible hill, about 12%grade for 1/4 mile. He said there was no problem coming up the hill, but when he got to the top it bogged down and then died. He stopped it, started started the engine and started riding and after 50 feet it bogged down again and died.

When I was looking at it and held up the back and throttled it, it seemed to run fine all the way open. I thought he was trying to baby the throttle, like the first day (which caused it to sputter and stall) but just when I was convinced he was just causing it to stall with not enough throttle it bogged down at full throttle and the clutch/transmission sounded clanky, but not grindy, and then it bogged out completely and stopped.

----------------------
He's only put about 8 hours on it since we got it. I've made sure he put premium fuel in it. It got a new fuel filter and oil change the day we bought it. I watched the seller change the oil and add a new fuel filter. Nice man.

I'm pretty handy. I work on my own cars and motorcycles and lawnmowers, but I've never dealt with Centrifugal Clutch Transmission before.

What can I test - and how - to help diagnose the problem correctly. Once I know what's wrong, I'm sure I can fix it or replace it. I just don't know where to start diagnosing it.

Thanks
ive put 1000+ miles on my bike. only problem I had was with the carbeuretor but I have since worked that out and havent had any problems. I go to work and back and go up and down somw pretty gnarly hills but it has always pulled through like a champ even if starting from a dead stop.
 
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