Harbor Freight 99cc friction build

[MaxPower]

The largest roller I could get was a 1.5" from dax. Do you know anyone selling a larger one?

The bike does have a hole for rim brakes but the channel's mounting bracket interferes with the operation of the caliper. The brakes were also not long enough to be mounted backwards on the steer tube.

 

[cannonball2]

How much room do you have- ie. whats the biggest roller you can get in the channel?

 

[MaxPower]

How much room do you have- ie. whats the biggest roller you can get in the channel?

I can probably fit a 3" roller. I'm thinking I'd like to find a 2" roller. at 6000 RPM a 2" roller would put me at 40 mph.

 

[cannonball2]

Can you run a 5/8 shaft in the existing bearings, or can you use the standard 1 3/8x5/8 bearings in the channel? If so then you can make your own roller.

 

[wayne z]

I can probably fit a 3" roller. I'm thinking I'd like to find a 2" roller. at 6000 RPM a 2" roller would put me at 40 mph.

If yer gonna change stuff, It's gonna cost money so you might as well get the most out of it.

I would use the largest roller that I could squeeze in there, and get the ratio right by changing the sprocket. You will not be dissapointed. The chain will also be way less problematic by running around a larger dia. sprocket.

Really if you want very smooth, very quiet and very maintenance free drive train, change to a belt clutch and pully. The roller's gonna slip anyway, before the belt will.

A 3" roller has WAY less drag, and way better efficency and friction drive than a 2". And with the torque of the Preddy, you need all the surface area that you can get.
Basicly, a 3"roller will slip some under full power accelleration, and a 2" roller will slip a lot.

 

[chrisc]

I just got the max-torque clutch from AGK and it doesn't quite fit the output shaft of the predator. It's close but it won't slide on without a hammer. I haven't went that far yet. I called AGK and left a message so hopefully they'll call back. Anyone know if it is supposed to be a press fit on the drive shaft or did I get the wrong size clutch?

Hi, I've been looking into the same predator engine as well and what I have read so far from at least 1 guy is that you need to dremmel down just a little bit on the shaft in order for it to fit the 5/8 ths because its a little bigger. Hope this helps.

 

[chrisc]

I thought I'd share what the project has cost so far. I haven't bought a bike yet and I'm still looking at yard sales and second hand stores. I'm thinking I may just go with a $90 walmart bike untill I find a better one.

HF Engine 90
friction kit 185
clutch 50
sprocket 5
shaft 13
throttle 5
reamer 12
total 360

Hi, wondering if you could tell me where you got the friction kit and other parts to used on the HF engine, thx.

 

[MaxPower]

Hi, wondering if you could tell me where you got the friction kit and other parts to used on the HF engine, thx.

friction kit: thatsdax.com
HF engine: harborfreight.com
clutch: affordablegokarts.com
sprocket/shaft: mcmaster.com
#35 chain: local engine shop

 

[wayne z]

Hi, I've been looking into the same predator engine as well and what I have read so far from at least 1 guy is that you need to dremmel down just a little bit on the shaft in order for it to fit the 5/8 ths because its a little bigger. Hope this helps.

Don't dremel on the shaft! Some ppl dremel the bore though. It is 16mm that is .630" Buy a 16mm reamer on ebay for $12 delivered, and ream the clutch bore. That's what I did. perfect slip fit. Or take it to a machine shop and have them ream it.

Some ppl here have had good results holding a file or emory cloth against the shaft with the engine idling.

 

[MaxPower]

Don't dremel on the shaft! Some ppl dremel the bore though. It is 16mm that is .630" Buy a 16mm reamer on ebay for $12 delivered, and ream the clutch bore. That's what I did. perfect slip fit. Or take it to a machine shop and have them ream it.

Some ppl here have had good results holding a file or emory cloth against the shaft with the engine idling.

I tried to ream out the clutch and sprocket with a drill press and had bad results. I had to buy a new sprocket and take the reamer and sprocket to a machinist. he charged me like $10.

 

[MaxPower]

http://motorbicycling.com/showthread.php?p=395140#post395140