In frame Predator fricton drive build

I can do the pressure adjust on my direct drives with the clutch cable on the fly. My Mongoose is a spring down engine, while the Schwinn is not. I feel a spring is needed as I have grabbed a lot of throttle on a hill and had the engine oscilate as it over ran the tire. Intend to add one. The lift clutch is perfect for pressure adjustment as you just tighten or loosen at the clutch adjuster on the handlebar. The weight of the engine alone is generally not enough even at around 20lbs for the torque they produce. A spring allows more pressure. When I am in an area of extended flat riding I will reduce the pressure assuming less tire wear. Who knows, but its pretty cool to mess with.
 
...I gotta re-read the info on your bike and look very closely at pics, CB2...

There's just SO much great information here from you guys I sometimes miss things that are important.

...very helpful to have such good information...

Tnx
rc
 
Well, It's been raining all day, so I wrung out the new 3.5" knurled roller in the rain today.

This thing grips WAY better wet than any of the other fricton drives that I have dealt with.

I easily accelerated on the flats, up to 35 mph. (went back to the 4" driven pulley) and easily maintained speed while climbing my street's steepest hill (very steep, and long). With a carefull handfull of throttle , there is very little slipping under all wet conditons. It even pulled good on my long muddy driveway.
And that's saying something, cuz this little engine is very torquey at mid range rpm. Any more power than this thing makes too much for a bicycle in my opinion.

The large dia roller on a jackshaft takes fricton drive to another level.

Smooth, quiet, fast, and NO CHAIN!
 
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OK, this thing is fast. I decided that it needed suspension and brakes on the front.
DSC_1572.JPG

The difference in ride and handling and stopping is like night and day. Feels much safer now.

I changed out the 5" jackshaft pulley for the 4". With a 3" motor pulley and a 3.5 " fricton roller for a 8.75-1 total ratio, Someone correct me if that's wrong. 9.08 with the 5"
Take off was better with the 5" pulley but the engine was racing too much at my desired crusing speeds around 25-30mph.
This lil engine seems happier grunting along with a heavy load at lower rpm than racing with
PHP:
a light load at higher rpm
THe difference in 5" and 4" driven pullies wasn't much on paper, but very dramatic in practice.
I like the manual belt clutch even tho it squeals in protest on dead stop take off, you can really feel what the roller is doing. With the cent clutch, I was never sure what was slipping .
Still wanna try a 4.5 belt pulley though. The 4" is kinda hard on the belt clutch on take off.

Unusual phenomina: the roller never slips on take off. The belt slips first. And this is in wet conditons.

This thing works very well in the rain. I can maintain whatever speed I hit the hills with, and accellerate easily on the flats.

This large dia roller works so much better than all the other FD's that I have experience with. I don't think a grinding wheel is needed for wet fricton .

NO CHAIN LOL
 
Wayne,
That's a beautiful machine you've made. I'm guessing many others will travel down this path you guys are blazing. The chain is a major hassle on every build I have done. There is little extra room on a bicycle for a chain to fit where it was never intended to have one. And belt drive has it's own hassles. Until now, friction drive left a lot to be desired. It appears to me that this approach shows a lot of promise at an affordable price. Well done.
SB
 
Great work, W !

just like SB said, chain drive on a china product is sketchy.
I just assembled two rag joints, (my first two!), and they are such poor quality it's laughable. Out of concentric, AND nearly impossible to get the warble out of the sprocket.

This thread of your work has created a big question for me...
Dump more money on the quality fabricated clamshell hubs w/new sprocket, or finish the build, as is, and build another with your friction drive.

It really does seem to be superior.

Question.

Are you getting effective engine braking on deceleration when you let off the throttle? THAT, is the major reason I don't want to use a centrifugal clutch.
then comes the cost.
Same thing with the TAV/CVT devices. Too expensive.

I am wondering if you would notice any change in operation if you increased the size of your idler pulley. a larger sheave would slow it's speed down, and maybe create less drag???

Best
rc
 
Thanks RC for the reply and questions.

Yes I get good engine braking with the manual belt clutch. I got some engine braking when I had the cent cluth/roller on there. It would brake some then release when the speed dropped some.
I don't think that idler size would make much difference, the motor has gobs of power for a bike.

I'm working and riding in the French Qtr in NOLA this week, I live in a rural area and the 4" driven pulley with 8.75 total ratio works well for me there.

I been running without the hotdog muffler here. It has a beautiful exhaust tone that everone seems to like. It don't sound loud in the noisy city as it does in the boonies.

I changed to a 5" pulley and 9.08 ratio, for the slower speeds and a lot of stop an go in the Qtr. Works perfect. Very easy no assist take offs with hardly any belt squealing, unlike with the 4". The ratio change don't sound like much, but in practice, it's very dramatic.
No rain last couple days and it's very hard to make the roller slip when it's dry.
This thing is awesome! So smooth and quiet. I have almost 50 miles on the new large knurled roller. Cant see any wear on the tire or roller yet. I haven't rode any of my other 3 MB's since I got this one running . It's my new favorite.
 
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Look in the 2 stroke forum, there's a long thread with quite a lot of info there.

There's a couple fresh posts there now, that will take you to the thread.
 
Well, I had a great time cruisin my new bike in the New Orleans French Qtr every evening this week. The sidewalks there are always packed with people, streets too sometimes.

Plenty curious people around to check out my unusual MB.

I was running the strait exhaust this week. It Isn't that loud if you stay off ham fisting the throttle. The wonderful throaty 4 stroke sound sure turned a lotta heads. All smiles, nary any frown.

I've been working and cruisin all my bike builds there for the last year. All the local shop keeps and hawkers and cops know me well and always want to see what new mb I come up with.

Got axked a zillion questions and many wanted me to sell it to them.

I finished my work there and won't be there for a while. Sure gonna miss all that good ridin and showin off territory :~)

I like the manual clutch so much that I'm gonna go on and cut the extra 1.5" of pto off to make more pedal clearence.

With a manual clutch, I can putt-putt along as slow as 5 mph for as long as I want.

With a cent clutch you have to maintain about 18 mph minimun to not wear the clutch.

I discovered that thanks to the Predator's automatic comp release, that this thing bump starts about the same as the HT's! Awesome !

Now it's time to work on making the roller assy lighter and easily adjustable, preferably on the fly.

If this thing proves to be safe and reliable, I may offer to sell a roller kit or components to anyone who wants to try one of these builds.

My new project is going to be another one of these with motor from my
BGF HS kit.
With it's built in clutch, I could make it centrifugal AND manual, like the old Cushman Eagles LOL
Great lil 49 cc legal engine.
 
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Oh man, bet that was some awesome riding! Most especially some of the more off the beaten trails parts.

"...the Predator's automatic comp release, that this thing bump starts about the same as the HT's! Awesome !"

I can't find any more information on the release? I still have yet to start my brandy new Predator but how is it in comparison to starting the Grey Hound 79cc?

I swear it seems lighter too but forget what the 79cc weighed.

I just happened to be sitting here staring at both engines thinking about doing a rotating arm/drive inframe FD when you posted. But think they are to wide.
 
My engine is mounted high enough that the pedal swing doesn't inrerfere at all. The clamp-on mount and adaptor plates ect take up a lot of vertical space. Puts the motor pretty far from the pedal swing.
My total motor width will be 9.25" when I cut off the pto shaft some.

This is about 1" narrower than my BFF kit that was on this bike.

My pedal crank has been re-bent to 7" wide. I can use all but about 1" of pedals on each side. Not hard at all to pedal.

Just more info for you to consider :~)
 
OK, I modified my jackshaft mount so that the fricton wheel pressure is easily adjustable on the fly by turning a thumbscrew under the seat.
I started with a large "T" hinge and some aluminum plate scraps and worked it out pretty good. Cleaned up the looks and shaved some weight. Still gotta tweak the idler and belt length some since things moved around some with the changes I made.

Was too late to take pix when I quit. They will be taken an posted in the morning.
 
Kinda heavy at 80 lbs wet, according to my rusty old bathroom scale, but with the engine in the frame, the weight is un noticable and balance and handeling are excellent.

Only time I notice the xtra weight is when loading it in my truck.

The 99cc engine takes care of that extra weight real good.
 
Kinda heavy at 80 lbs wet, according to my rusty old bathroom scale, but with the engine in the frame, the weight is un noticable and balance and handeling are excellent.

Only time I notice the xtra weight is when loading it in my truck.

The 99cc engine takes care of that extra weight real good.
 
Thanks for posting all this Wayne!

I'm having rag joint/tensioner probs right now... the belt drive friction is looking real good about now... even better!

Best
rc
 
Hey RC, thanks for the kudos. I gurantee that if you decide to build one of these, you will not be dissapointed. You will be exhillerated![

I'm ruined now,I could never be happy with just riding an ol smokey noisy rattlely 2 stroke chain drive MB again.
 
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Ok, here's some pix of what I did with the large t hinge to make the roller pressure easily adjustable.

Had to make the handle sorta small because of my offset seat post. works great though.

DSC_1581.JPG

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DSC_1578.JPG

Painted the exhaust system and some other stuff.

This thing Rocks! I'm goin to go cure the exhaust paint now>
 
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