Harbor Freight 99cc friction build
- Thread starter MaxPower
- Start date
wayne z
Active Member
Man, That's a great idea!. Can't wait to see what you come up with. The Preddy's look so right with the cylinder facing foreward. Makes the intake and exhaust easier to deal with too.
I have a couple nice suspension bikes and couple more small 4 strokes that could be adapted to this type mount. Have you seen my in frame preddy fricton drive thread, and Cannball2's multiple threads on jackshaft driven fricton drives. Plenty good info about roller sizes, ratios ect.
One thing I would recomend right off is to use a belt drive on the jackshaft. The chain drives are problematic. The fast moving chain is noisy and wears quickly and needs plenty maintenance.
From my experience,the belt is quiet and smooth, hardly ever needs attention, long lasting, delivers more than enough torque to drive a roller. The roller will slip before the belt.
I would also spend the few extra bux for the Maxtorque clutch with the sealed bearings instead of the bushing. The bushing clutches are high maintenance more noisy.
Another thing that helped my FWD bike not fall over so easily from the kickstand was to add an axle mount kickstand to the front axle.
Good luck with your build.
I have a couple nice suspension bikes and couple more small 4 strokes that could be adapted to this type mount. Have you seen my in frame preddy fricton drive thread, and Cannball2's multiple threads on jackshaft driven fricton drives. Plenty good info about roller sizes, ratios ect.
One thing I would recomend right off is to use a belt drive on the jackshaft. The chain drives are problematic. The fast moving chain is noisy and wears quickly and needs plenty maintenance.
From my experience,the belt is quiet and smooth, hardly ever needs attention, long lasting, delivers more than enough torque to drive a roller. The roller will slip before the belt.
I would also spend the few extra bux for the Maxtorque clutch with the sealed bearings instead of the bushing. The bushing clutches are high maintenance more noisy.
Another thing that helped my FWD bike not fall over so easily from the kickstand was to add an axle mount kickstand to the front axle.
Good luck with your build.
killercanuck
New Member
cool wayne. don't forget Lowracers builds, eh? 
from this thread: http://motorbicycling.com/showthread.php?t=35012
I know, not the same... Cag vs Pred, still good tips on mounting though
Can't wait to see what you come up with Max.
gl.
from this thread: http://motorbicycling.com/showthread.php?t=35012
I know, not the same... Cag vs Pred, still good tips on mounting though
Can't wait to see what you come up with Max.
gl.
MaxPower
New Member
Do you know where I can get a belt style clutch with the proper engagment RPM? Stock maxtorque clutches engage pretty high. I was also thinking of a CVT but I could not find a driven pulley that would fit the 5/8" shaft.
wayne z
Active Member
Contact the Maxtorque company directly by phone or email. They're real friendly and will take time to answer any questions. Last year the good bearing belt clutch was around $80 I think.
Go to AGK website. he sells torque converters and jackshafts to fit the Predator. The shaft is actualy 16MM or .630". I bought a 16mm chucking reamer for $14 shipped. I use it to fit 5/8 pullies to my engines now.
You should mount the engine as far back towards the handlebars as you can. All that weight foreward on the front wheel will affect handeling and balance.
Since you can easily adjust ratios, go ahead and use a large 3"
or so roller. Maybe even a small Go-ped tire/wheel with brakes? Larger dia. dramaticly lessens roll resistance and power loss from drag forces of the tire/roller working agaist each other .
Go to AGK website. he sells torque converters and jackshafts to fit the Predator. The shaft is actualy 16MM or .630". I bought a 16mm chucking reamer for $14 shipped. I use it to fit 5/8 pullies to my engines now.
You should mount the engine as far back towards the handlebars as you can. All that weight foreward on the front wheel will affect handeling and balance.
Since you can easily adjust ratios, go ahead and use a large 3"
or so roller. Maybe even a small Go-ped tire/wheel with brakes? Larger dia. dramaticly lessens roll resistance and power loss from drag forces of the tire/roller working agaist each other .
cannonball2
Well-Known Member
Maybe this link will help you. Keep the engine as low and as close to the handle bars as possible. This set up feels a little weird until under way a few mph either under power or pedaling. Once its rolling its a solid ride, and feels more stable the faster it goes. Nothing is quite like it.http://motorbicycling.com/showpost.php?p=292068&postcount=1
MaxPower
New Member
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?
jowens
New Member
Max I have read on here with previous builds it is a very very tight fit...cant remember if it was just hammered on to make fit or if some sanding /grinding was required....if Im not mistaken scotto was an individual that posted but let us know what AGK says about it.....Im about to be doing a 99cc HF build myself and would like to know....good luck
wayne z
Active Member
The Preddy's shaft is 16 mm.(.530") I've used Preddys on 2 builds. I found that the easiest thing is to buy a 16mm reamer on ebay for 14 bux delivered.
Once the pully is reamed, you can tap it on easily with a hammer and block.
Prolly could get a local machine shop to ream it for ya for about the same price as the reamer.
Some people file or sand the shaft until it fits. I feel like .005" is a lil to much to remove by hand accuratly.
cannonball2
Well-Known Member
If you look at the pic the engine is centered on the channel, and will be centered over the front wheel. Will have a jackshaft driven roller.
MaxPower
New Member
I really annoys me that AGK advertised the clutch for the 99cc but it doesn't fit without extra work. This same thing happened to me with dax when they said the bearings were easy to remove from their friction drive. I had to buy a bearing puller and modify it with longer arms to get the bearings off. AGK needs to include this work in their price or denote that you need a reamer to finish the job. I'm going to mention it to them when ever they call me back.
cannonball2
Well-Known Member
MP the fault lies with HF selling a non-standard crank. We have all had to negociate this with this engine. I agree with Wayne on reaming the pulleys, clutches etc as best. I just went with the hand done method and carefully reduced the dia. with a strip of 50 grit sanding belt took about 30min. Maybe AGK should have given a heads up, but probably figured its a well known problem.
wayne z
Active Member
Oops ,Typo, 16mm = .630
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Thought I'd chime in on the faux pas Wayne,but I see You caught it I too had the clutch problem with My 99cc predator/Schwinn friction dr....Being a Machinist has its advantages,I disassemble it and chucked the hub in the Lathe and bored it and with the digital readout on the Lathe its right at a comfortable .635(16.129032mm).My engines crank is also .630(16.002032mm)The ream works great to!....I did it both ways and both slip/no hammer or deadblow needed....Tigmaster....Edit...I saw a vid of some back yard machinin' done with the engine running and attacking the spinning shaft with a sidegrinder!...Was taking off more than a few thou.....He was turning it from 1 inch down to 3/4 !.....
I too had the clutch problem with My 99cc predator/Schwinn friction dr....Being a Machinist has its advantages,I disassemble it and chucked the hub in the Lathe and bored it and with the digital readout on the Lathe its right at a comfortable .635(16.129032mm).My engines crank is also .630(16.002032mm)The ream works great to!....I did it both ways and both slip/no hammer or deadblow needed....Tigmaster....Edit...I saw a vid of some back yard machinin' done with the engine running and attacking the spinning shaft with a sidegrinder!...Was taking off more than a few thou.....He was turning it from 1 inch down to 3/4 !.....
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MaxPower
New Member
Do you have a link?
jowens
New Member
all you have to do is type "16mm reamer" into the search bar on Ebay and it will bring up a few!......heres one for you.....http://www.ebay.com/itm/Machine-HSS...t=LH_DefaultDomain_0&var=&hash=item5f78c4a767....or maybe these are better (I typed "hand 16mm reamer")........http://www.ebay.com/itm/HSS-HAND-RE...663?pt=LH_DefaultDomain_0&hash=item2568494aaf..................................................................................................................................................http://www.ebay.com/itm/T-C-MCGEE-H...663?pt=LH_DefaultDomain_0&hash=item2568494aaf
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