Chain keeps coming off, not sure why

alxx01

alxx01

Member
#1
#1
Chain keeps popping off but everything seems fine?

Put a pred 212 on a Manco Streaker, everything fit but the chain keeps popping off after short rides. Everything seems lined up so I’m confused. There is a tiny bit of play on the rear wheel but I didn’t think it was enough to cause any issues. Chain seems perfect when I put it on until it falls off. Any advice?
 
Minimichael

Minimichael

Well-Known Member
#2
#2
What size chain and how many teeth on the clutch? And whaddya mean play? Forward and back at the axle? Or wheel sliding left to right?
 
Last edited:
alxx01

alxx01

Member
#3
#3
Minimichael said:
What size chain and how many teeth on the clutch? And whaddya mean play? Forward and back at the axle? Or wheel sliding left to right?
Click to expand...
it’s a 35 chain 12t clutch and 60t sprocket. The play is left to right. i added a spacer and washers and it doesn’t seem like i’d even be able to fit another washer to close the little bit of the gap there is.
 
pomfish

pomfish

Well-Known Member
#5
#5
Engine plate is flexing under load.
Bike came with 3.5hp and now you have 6.5+

If you look at how the plate just kind of hangs out there it is not surprising.
Have it happen on Manco Thunderbirds a lot as well.
Need to beef up that plate and add another side support across width of frame.
 
Thepaetsguy

Thepaetsguy

Well-Known Member
#8
#8
You cannot use bearings that cost $5 they will not work AT ALL for a minibike/gokart application.

Get some high speed wheel bearings go to T@S for the wheel bearing spacers and do it correctly and have fun.

My chopper rear tire is ROCK solid.. Besides doing it right with the spacers/bearings the only way I know to get rid of the slop is to weld in a live axle. A live axle is what the mini bike racers use and there doing 80+ mph
DDABE0DE-BDED-4046-AA84-459C6787CF50.jpeg 7965E191-4AB2-4528-8B05-A22205DD3C06.png
 
sparkwizard

sparkwizard

#9
#9
Spacers good. They are a piece of pipe that only touch the inner race of the bearing, not the black seal.
Washers bad. They may take up the slack for now, but they drag on that black seal and can overheat the grease and melt the seal.
 
Last edited:
Thepaetsguy

Thepaetsguy

Well-Known Member
#10
#10
T@s sells REAL bearing spacers in normal and HEAVY wall.

The bearings in this photo are junk and should not be used ever..

Spacers in this photo are from t@s with a set of high speed wheel bearings and spaced correctly will completely 100% fix all wheel slop.

The bearings in my back wheel are I think the 70’s originals and still there is zero slop.

If there is slop in the back tire (at all) I would always be worried it’ll get much worse.. Then the chain doesn’t stay on.. And I have to push it home.

If you go to a live axle you gain the option of a split sprocket hub for a quick change rear gear.

6BB3C406-988F-4521-8855-F0429FB8A080.jpeg
 
Thepaetsguy

Thepaetsguy

Well-Known Member
#12
#12
sparkwizard said:
I also install a tight-fitting pipe type spacer inside the wheel, between the bearings. That way, I can tighten the axle bolt without putting any side load on the bearings.
Click to expand...
I never pulled the rear wheel on the chopper but I assume there is a spacer in between the bearings.

There (Should) be a lip inside the rim that allows the bearing to sit in the pocket flush. So when you tap the bearing into the wheel it just doesn’t go straight into the center of the rim.

When the spacer is made between the bearings for inside the rim it should be made so it crushes just a bit when the bearings are flush into the rim on each side.

The spacers for the outside of the wheel are to get the tire centered and align the sprocket bolted to the rim to the clutch. Good thread refresher on standard stuff.
 
alxx01

alxx01

Member
#13
#13
Thepaetsguy said:
You cannot use bearings that cost $5 they will not work AT ALL for a minibike/gokart application.

Get some high speed wheel bearings go to T@S for the wheel bearing spacers and do it correctly and have fun.

My chopper rear tire is ROCK solid.. Besides doing it right with the spacers/bearings the only way I know to get rid of the slop is to weld in a live axle. A live axle is what the mini bike racers use and there doing 80+ mph
View attachment 314473 View attachment 314474
Click to expand...
i have brand new high speed bearings in
 
alxx01

alxx01

Member
#14
#14
sparkwizard said:
Spacers good. They are a piece of pipe that only touch the inner race of the bearing, not the black seal.
Washers bad. They may take up the slack for now, but they drag on that black seal and can overheat the grease and melt the seal.
Click to expand...
if i put the spacer against the bearing and the washers on the opposite side would it work for the time being?
 
You must log in or register to reply here.
Top