qestions about a 99cc pred build

My Preddy is geared to 10.75:1 and gets 40 mph at 5600 rpm. You prolly need around 12:1 to pull hills and have relatively easy takeoffs at your weight..and a good cruise around 30 mph.

There is a gear calculator in the DIY forum at the top of the list.

No need for an extra bearing and plate for the engine's pto shaft. They are designed for an overhung side load.
Now, I did use a backplate bolted to the engine, and an outboard plate, to mount my jackshaft and bearings.

Inatead of all that fabbing, I'm using one of these for my next jackshaft .
http://www.ebay.com/itm/330717252331?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2648

Look forward to seeing pictures.

Wayne, that's a good deal for that backing plate and jackshaft bearing included. Thanks for posting the link. Making my own would take a good bit of time then deduct the cost of materials and what are you saving? Not much.
SB

silverbear said:

Look forward to seeing pictures.

Wayne, that's a good deal for that backing plate and jackshaft bearing included. Thanks for posting the link. Making my own would take a good bit of time then deduct the cost of materials and what are you saving? Not much.
SB

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Yeah, I paid $40 for just the raw aluminum plate for my fabbed jackshaft, and about 20 hours labor to design and build it.

Way cheaper and easier to buy this backplate.

I've bought the plate recently. Going tomorrow to get another Preddy. Got a 20% coupon out of a Popular Science mag at the doctor's office this week

wayne z said:

Yeah, I paid $40 for just the raw aluminum plate for my fabbed jackshaft, and about 20 hours labor to design and build it.

Way cheaper and easier to buy this backplate.

I've bought the plate recently. Going tomorrow to get another Preddy. Got a 20% coupon out of a Popular Science mag at the doctor's office this week

Click to expand...

Take pictures and please do a build thread. Will this have a variable speed tranny?
SB

Wohoo! I got my new Preddy 99 for $87 and change with the 20% coupon, and a free multimeter with
$10 or more purchase with another coupon.
The shaft is actual .624"

SB: If I use this backplate with the vari-pully, I will have to offset the engine 1.75" from centered to get the final belt center in the right place, because of the 2.25" jackshaft bearing stub on the back.
The 99 preddy is a tad less than 12" wide from starter housing to the end of crankshaft. My 2 speed's engine is perfectly centered, 6" each side.
This means the clutch will stick out 7.75 from frame center, and the starter will stick out 4.25 on the other side to use the varipully and have rear belt alignment.
With a standard pulley, one would only need to offset the engine 3/4" from centered to get rear belt alignment. So I haven't decided yet wether I want that much offset or not. But it would keep the air cleaner from sticking out so far. Since I dont pedal at all, one crank more offset than the other shouldn't matter much.

Hey KLB,here's a pic of my 2 speed jackshaft assembly with outboard bearing.

At first I tried bearings without concentric or allen screw locks, and the shaft galled pretty bad under the bearings due to the slight slack in their fit.

I changed to allen lock collar bearings and have had no problems at all in the 200 miles of service so far.

Hello klb6154,I'm right with Ya in the lbs. area,and I have a Predator on a Schwinn Legacy I'm changing from friction drive to chain drive,I just figgered how to post pics and all of the pics I have are to big to post of the f/d,but I have started a new thread in the dyi sec. on the change....Warning may be picture heavy....Tigmaster....

klb6154 said:

So that set up uses a variable speed pulley?my set up depends on weather or not my china girl sells. Its nothin spectacular just a grubbee st5 mounted in a modified cranny frame w a 6spd rear wheel and a lowered straight springer frnt. Stubby crank and apes. But I got many hours polishing the case n covers. I've also fabbed my own over the top header and made a small exp muffler. Hey do u know how to send pics to here via txt msg? I don't have internet or the time to sit @ mcds wiifii.

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Yes, I have a variable pully from Mcmaster Carr on the jackshaft output. I had to modify it and add a bike shock spring to get enough belt tension. When I pull the shift lever, the idler tightens the belt enough to spread the pully for a lower ratio.

Can't help you with text msg pics.