first bike... schwinn predator 99cc friction drive project

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beltbuckle

New Member
Aug 22, 2011
81
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Meridian, ID
finally got my first build nearing completion. still need to make an exhaust, might add a belt tensioner, and extend the pedals out a little bit.

Engine is a great fit, has a great sound. still playing with roller tension, roller starts slipping at around 25-30MPH. Once I get that tension higher it should go around 35MPH near the top end. It loves to cruise around 20-25 which is perfect for me.




turnbuckles adjust the roller tension




exhaust still in the works.
 
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wayne z

wayne z

Active Member
Dec 5, 2010
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louisiana
Awesome, that looks sorta familiar to me. You're gonna love the lil Preddy and the very low maintenabce of a friction drive.

These lil motors look so right with the cyl facing foreward.
I realy like your engine mount design. Much lighter than the ol BGF clamp ons.

I see that you went with a larger sized roller. Good choice for way more drive train efficency. Rubber does better than steel when wet

I used a steel roller on mine. It would slip just a little at full throttle accelleration, but it causes no problems or excessice tire wear.

It does slip a lot more in wet conditions, but still will get you home better than the normal small dia FD under the same conditons.

honestly. I never ride much in wet conditons anyway.
 
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beltbuckle

New Member
Aug 22, 2011
81
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Meridian, ID
thanks! yeah got lots of ideas from your build and others on the forum. so far i've only done about 10-15 miles but am loving it.

engine mount is 6061 aluminum angle, with aluminum aircraft tubing saddles, and AN washers sized to fit, with AN bolts and locknuts. i think it will hold up but time will tell.

 
rustycase

rustycase

Gutter Rider
May 26, 2011
2,746
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Left coast
All the drivetrain noise and vibration you are missing out on! lol
and the cylinder leaning properly forward...
I like it!
rc
 
cannonball2

cannonball2

Well-Known Member
Oct 28, 2010
3,682
221
63
Colonial Coast USA.
Nicely Done build! My experience with rubber drive rollers is that they form to the tire after a bit of running. Initially they slip, as does a new tire due to the wax most are dipped in to preserve them(stuffs hard to clean off!). The grip should improve shortly. Good down thrust is a must. You should have most of the roller deflected into the tire. Conversely I run lower pressures than most people. I use 30-32lbs on a cruiser tire. I dont see increased tire wear, the ride is good and the bite is great. A Preddy could care less about pressures, unlike the smaller displacement engines. If the rubber compound wears too fast for ya, just remake the roller in oak, you will never wear it out! You are gonna love that bike! Once again great job!
 
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beltbuckle

New Member
Aug 22, 2011
81
5
0
Meridian, ID
Sweet thanks. Didn't realize the roller needs to be pressed in to the tire that hard but I'm going to increase the bite when i get home. rode it to work this morning 6 miles, no issues. these bikes sure get a lot of head turns and smiles.
 
pocdragon

pocdragon

New Member
Apr 30, 2011
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RI
awesome build!

looks like a whizzer!

super sweet, i love FD!

GL
update on howmany miles you can get on the rubber roller

.trk
 
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beltbuckle

New Member
Aug 22, 2011
81
5
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Meridian, ID
ridden maybe 15 miles or so, the adjustable link belt just isn't going to work, doesn't have enough grip for this kind of power. Kind of expected this, but I thought the roller was slipping when actually it was the belt.

went to autozone and found an automatic belt tensioner made for a serpentine belt and a 27" v-belt that I think will do the trick. had to trim the belt guard to make it fit but I think this will work well. planning to ride to work tomorrow so I'll see how she does.



rear pulley alignment is off a bit, will fix this when I pull everything apart for paint.




Made some little spacers to keep the tensioner away from the 1"x0.25" steel bar to keep it close to centered on the belt.



clutch cover "rough trimmed"... will have to clean that cut up when I paint it again.

 
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beltbuckle

New Member
Aug 22, 2011
81
5
0
Meridian, ID
Well just got done with a 6 mile ride. HUGE improvement. Now there is nothing slipping at all in the drivetrain. Belt tensioner worked perfectly.

Next thing to try is maybe a slightly bigger (or variable) pulley in the rear. the 3" is a great cruiser but a little slow off the line.
 
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DTFuqua

New Member
Jul 16, 2012
76
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0
Florida
Hi. I have a shwinn and am trying to get the same setup as you. can you tell me/us what the drive wheel/roller is and how mit fits the keyway on the jackshaft? Pleas and thank you.
 
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