4 stroke clutch bell rotor broke???

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worksuxxx

New Member
Jul 16, 2013
135
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0
Omaha
Ordering a new one today. But how on earth does this thing break like this. Really nervous about venturing far from home if there is an underlying problem that will cause this to happen again. Any input anyone? OH, I only have put on about 20 miles on this bike prior to bell rotor breaking.
 

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worksuxxx

New Member
Jul 16, 2013
135
0
0
Omaha
To answer my own question, as well as warning anybody else. I talked with a lead tec over at BikeBerry a little while ago. They are sending me out the parts under warranty, but he did warn about the possible cause. Do not throttle heavily from a dead stop, also if cruising at any speed with engine at idle, do not WOT. The clutch engages, spins the bell rotor at high rate of speed. When it catches up to the speed the sprockets are turning the bell rotor is at a much higher speed and under torque and causes stress. So ease the throttle until you feel engagement.
 

worksuxxx

New Member
Jul 16, 2013
135
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Omaha
Ok I just counted the teeth in the transfer case. Front 7t rear 41t. So this is a 5.86.1 ratio transfer case.
With the drive sprocket being a 10t, rear sprocket being a 50t, I am running a whopping 29.29 to 1. Which means at redline (7800 rpm) I should be at 23 mph. So taking it to 25 mph via my gps, I was running at 8500 rpm.
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
Ok I just counted the teeth in the transfer case. Front 7t rear 41t. So this is a 5.86.1 ratio transfer case.
With the drive sprocket being a 10t, rear sprocket being a 50t, I am running a whopping 29.29 to 1. Which means at redline (7800 rpm) I should be at 23 mph. So taking it to 25 mph via my gps, I was running at 8500 rpm.
Wow.....that puppy was screaming..........!
 

MtDandy

New Member
Aug 14, 2012
15
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0
Australia- Melbourne
G'day. I also have one of those gearboxes (thru powercycle Australia) fitted to my HS49cc engine.. I have found that the clutch ( the 3 pad style)does not fit snug into the bell housing. approx quarter inch mismatch. This then means the clutch pads are sitting outside the bell housing , and makes the clutch engage misappropriately, causing massive heat problems in both gearbox and engine. A spring breaks in the clutch mechanism due to heat load, and the gearbox ceases to work. After several ,clutches to work out what was going on i have decided to purchase a G4 grubee gearbox and sik kit to suit. I hope the grubee fits a lot better to the engine. cheers.
 

Tang

Member
Sep 29, 2013
72
1
8
Indianapolis
Guess thats why my clutch bell housing broke. I think a better trans i dont have to baby will be a better fix.


dance1

Tang

The trail life for me.
 

16v4nrbrgr

Active Member
Mar 17, 2012
1,728
4
38
North Bay
Check out pocket bike boxes, a lot of people set up their two stroke clutches to hit hard at around 8000 rpm, so the manufacturers use a bell with the dust vents located further outward from the axle, and they're welded all the way around.
 

MtDandy

New Member
Aug 14, 2012
15
0
0
Australia- Melbourne
Ordering a new one today. But how on earth does this thing break like this. Really nervous about venturing far from home if there is an underlying problem that will cause this to happen again. Any input anyone? OH, I only have put on about 20 miles on this bike prior to bell rotor breaking.
It will be the heat generated from the clutch pads. they dont seem to fit into the bell housing neatly. please see my notes below. Hope this helps. Im yet to find an answer, so i just ride it shorter distances. cvlt1
 

16v4nrbrgr

Active Member
Mar 17, 2012
1,728
4
38
North Bay
Try out the two stroke ones for pocket bikes, believe me, they're freakin' awesome, and they fit the HS49!

:D
 
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