Penton 100 Gearing/Chain Question

SouthRider · March 05, 2008, 11:24:59 AM

My little 100 project is coming along well. I am curious as to what gearing & chain length I will need.

Unfortunately the chains on the bikes I dismantled were so rusted that I cut them off & threw them away without measuring the length.

I bought a 12 & 13 countershaft sprocket & a 57T rear sprocket, and planned on experimenting - but I need a starting point to buy my chain.

What are most people running in the woods?

Thanx,

Clark

Ernie Phillips · March 05, 2008, 01:28:32 PM

Clark,

I have been buying 130 link, 428 EK O-ring chain and cutting to the required length. If you are building a steel tanker this should work with almost any sprocket combo. If on CMF you might have to move axle all the way up. I had to add 2 links (132) when running 60/13.

We ran 54/12 on our 100 last weekend. With light weight (140lb) riders on hard-pack surface, it did fine.

Ernie P.
Chattanooga, TN

SouthRider · March 05, 2008, 01:51:05 PM

Thanks Ernie - i really appreciate it.

Clark

1979 SERA Louisiana State Champ

Ron · March 05, 2008, 03:30:11 PM

I like o-ring chains for longevity, but they do rob power.
A scarce commodity in a 100cc.
RonW

SouthRider · March 05, 2008, 03:56:27 PM

Right - I'm going with a gold non o-ring chain.

Thanks again.

Ernie Phillips · March 05, 2008, 04:08:05 PM

Ron, Down south, we reduce 0-ring friction by using a special chain lube: semi-synthetic boiled okra slime with a splash of bacon grease[

)]

Ernie P.
Chattanooga, TN

brian kirby · March 05, 2008, 04:22:21 PM

As Ernie said, Kid Christopher and I are around 140lbs and the bike had 12/54 gearing last weekend. It had a straight that I was wide open in top gear on a 450 Maico, but I only used 4th on the Berkshire. Using the theory that you want to top out in 6th on the fastest straight I think we could easily have used 12/57 or 12/60 and had no shortage of top end speed. As long as you dont top out too early in 6th, I would use as low a ratio as I could on a 100 to keep the gaps between gears tight to make it easier to keep it on a boil. This will force you to shift more, but helps acceleration out of corners. The Sachs is the only 6 speed in the class, take advantage of it.

Brian

Dwight Rudder · March 05, 2008, 10:12:42 PM

Quotequote:Originally posted by Ron

I like o-ring chains for longevity, but they do rob power.
A scarce commodity in a 100cc.
RonW

A modern oring chain that is broken in and warmed up has no more power loss than a non oring chain. Much more reliable too. If there is any measurable power loss it would be only a tenth of a hp. or so.
Dwight

Dwight Rudder · March 05, 2008, 10:18:52 PM

Clark, Mike Burgess should know exactly what gearing to run. He was a 100cc Penton specialist.
Dwight

Ron · March 06, 2008, 10:40:59 AM

Ernie,
Haven't you heard about the on going problem with high cholesterol, LOL.
I had a guy tell me he couldn't pull 6th gear after he installed a new o-ring chain on a 6day 125. He said he went back to a standard chain and got it back.
However, I don't think it would have that effect running 12 x 57 gearing.
I still think I'd run one if I was riding in mud though.
RonW

Dwight Rudder · March 06, 2008, 02:31:30 PM

Quotequote:Originally posted by Ron

Ernie,
Haven't you heard about the on going problem with high cholesterol, LOL.
I had a guy tell me he couldn't pull 6th gear after he installed a new o-ring chain on a 6day 125. He said he went back to a standard chain and got it back.
However, I don't think it would have that effect running 12 x 57 gearing.
I still think I'd run one if I was riding in mud though.
RonW

I only had this problem when we were running Diamond Oring chains back in 1981 on my Suzuki PE125 and that was for only about 50miles.
New Oring and Xring chains do not require that much break in . Once warmed up they don't have any measureable drag.
If it will fit, I will run a Oring chain. BUT, not all bikes will allow the slightly wider Oring chain. I couldn't run one on my 1972 K100GS Hercules. Wouldn't clear the chain guide.
Dwight

Ernie Phillips · March 06, 2008, 03:54:36 PM

The Big Chain Block #51-07-066-400 from Al B. will work with 428 o-ring chain on steel tanker and CMF 100/125. Put the skinny side toward the tire. May require adjusting guide slightly (bend it). Get additional clearnance by running a smaller tire: 3.50 on steel tanker or 100/100 CMF.

Ernie P.
Chattanooga, TN

Mike Burgess · March 18, 2008, 11:22:16 PM

Well Clark,

How's that sweet little thing coming? From the pic's you sent me this is going to be one sweet bike. Congrats on all the hardwork you and dad have done on this project. Show's a true commitment to keeping up what we always lived for. To live and ride!

Mike Burges Jr.

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Penton 100 Gearing/Chain Question