100cc D cylinder

[brian kirby]

At a 100cc race this year there was a Penton with a D cylinder on it. I did not know that there were any 100cc D engines, or maybe it was a 125? This person believed the bike was a 100 but never took the cylinder head off to measure the bore. Could you put a 100 sleeve in a D cylinder?

Brian

[OUCWBOY]

Brian, I think they did make a 1001 D. Not sure they were ever used by Penton, but as I recall Monark may have used a few.

Donny Smith
Paragould, AR

[rob w]

Monark never offered a 100cc bike. Wallenberg's famous 100 (which I personally saw him race at Byron) was custom built using a 100 DKW top end.
Bob

[brian kirby]

I'll bet DKW/Hercules sold some 100s with D engines.

Brian

[Larry Perkins]

I never remember seeing anything but A and B 100cc motors in Pentons.  Rod Gorzney had one of the last ones produced at one time.  Rod, what motor did that have in it?  My guess on the D 100 at the races was if this guy was giving himself an out he probably knew it was a 125.  As in the past, today there will be a decent amount of fudging in the 100 class.  At big races back in "The Day" there was most always a 100 or two torn down under protest.  Brother Ron Carbaugh once threatened to protest any 100 in front of him at the finish the next weekend.  Funny how the next weekend he won.  Methinks that several of them got smaller that week.

One other thing to remember is that the "D" was not that different from a "B"(mainly the intake).  The one that was way different was the "D GS".  This one was a whole different animal.

Larry P

[brian kirby]

Thats kinda what I figured Larry, he may get protested eventually.

Brian

[Dwight Rudder]

There were never any "D" 100 Sachs engines.  Only A, B, & C engines.
There were some very hot factory ported engines.  Rick Grant had a GS100/6B powered 1975 Hercules with a factory cylinder.  Very Hot. Ran like a 175 for about 30 miles before it would eat a ring.  The exhaust port needed a bridge.
The D cylinder was a completely different and easily identifiable setup.
Dwight

[Ernie Phillips]

Brain,  I don't know about the D-100, but I have a D-125 and it is nothing special performance wise - strong running: yes, but not 'killer'.  As others have stated, it is the GS cylinder that is special.  I think the GS cylinder can be identified by its 35mm intake spigot. I don't know if Sachs ever make any 100 GS cylinders.  But, as you well know, a properly prepped mostly stock (unported)125 will carry one to the winners circle even beating the trick CZs. In the 100 class, I feel the Hodaka engines have evolved way beyond what a stock Sachs 100 can deliver.  Thus, the reason for our tuning efforts - pipe, PVL, bumping up the compression ... but with stock 48mm bore and unspoiled porting.  Rider skill is still the most important factor but it is fun to try and improve engine performance, rideability and reliability.

Ernie P.
Chattanooga, TN

[Rocket]

Larry
The 77 100 that I use to own has a 6B engine.  I know the guy who has it now, if you need more details.
Rod

[firstturn]

Who owns it?  You can send me a email.

Ron Carbaugh