What fits what questions

[warhammer]

In a batch of MC Stuff I bought there is a 76 MC5 roller, several sachs 125 engines and a May of 72 Penton 125 frame , wheels and tank.
I have always wanted to have a Penton and would like to build a couple of riders if possible.
What forks and triple clamps would the 72 frame take?
Will a Sachs engine fit in a 76 MC5 frame?
Finally any easy way to externally tell a six speed motor if it does not have the engine side cover with the model number?

Sorry for so many questions.

Jeff

[firstturn]

Jeff,
  Shoot me an email.  I live in Kerrville and will be happy to help you.

firstturn at hotmail.com

Ron Carbaugh

[ALB]

Jeff, you are very fortunate to have Ron Carbaugh assist you with your questions.

For those of you who are reading this post, here are my answers to the questions:
The 72 frames came with 32mm Ceriani forks. You can also install 35mm Ceriani forks which stronger (will not flex and bend as easily as the 32s)
A Sachs engine will fit in a 76 MC5 frame but in order to make it fit engine mounting plates would have to be installed. Look at the 72 frame that you have and compare it to the MC5 frame. Since the Sachs engines use a 428 chain and sprocket - coming up with a rear 428 sprocket is important to make it work. I have a 72T 428 sprocket to fit the MC5 in my inventory.

It's easy to identify a 5 speed engine - not so easy for a 6.
If there is a cast iron cylinder - there is 90% chance that it is a 5.
If you look at the center hole of the mainshaft (where the counter shaft sprocket is located) and the center hole is 7mm I.D. it is a 5 speed and also an "A" engine.
If the center hole is 9mm I.D. it could be a 5 or a 6 "B" engine. You would then have to shift through the gears and count how many gears that there are.

Alan Buehner

[hankthecrank]

I'm thinking I heard or read that the grommet for the ignition wires is round on a 5spd and has a flat side on a 6spd? Or did my brain just dream that one up? Al? Anybody? I'm very suspicious of things I think I remember. Hank

Hank Rinehart

[warhammer]

I have emailed a couple of times around with Ron now. He is graciously sharing info.
Al - on an MC5 that was originally a 125 will a 250 or 400 motor drop in or are the motor mounts different for those as well?

[ALB]

The MC5 frames were built for the KTM engines. Since the 125, 175, 250, and 400 engines all use the same center case gaskets, any of these engines will drop in and bolt up to that frame. The only difference will be the mounting tabs for the exhaust. Those might have to be modified.

On the Sachs engines there are 2 types of holes in the right side engine case. A round hole and a slotted opening. The round hole is for the wiring for the Bosch ignitions (points and condenser). The slotted hole is for the Motoplat ignitions.
If there is a round hole, there is a good probability that the engine is a 5 speed especially if the engine came from a Penton. However, depending the bike brand that the engine came from, it could also be a 6 speed. Sachs built and supplied engines to the specs that Bike manufacturers specified.
The early Penton Steel Tankers came with Bosch ignitions and were switched over to the Motoplats before the 6 speed engines were developed.

Alan Buehner

[warhammer]

Thanks for the reply. The motor on the MC5 is a 125 but is incomplete. I guess I will keep my eye out for a larger engine that is more complete for a rebuild.

[454MRW]

The 1977-80 KTM 175 engine would be the best choice in my opinion to put in a 125 MC5  frame, as the centrally located exhaust pipe mount, just ahead of the right hand upper shock mount by the airbox interferes with a 250 or 400 pipe, but is the same on a 175 pipe. Gary Ellis 217-260-0237 might be able to help you in obtaining an engine and pipe that will work for you. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R

[warhammer]

Thanks for the reply. The motor on the MC5 is a 125 but is incomplete. I guess I will keep my eye out for a larger engine that is more complete for a rebuild.