Explanation of Sachs "6D" motor?

[penton117]

Hi Guys,

There is a 1974 Six-Day on Ebay, which is said to have a "6D" motor. Can someone explain this "6D" designation to me. I think I undersand that the 6 means six gears, but what is the difference between a 6D and a 6C or 6B?

Thanks

 

[OUCWBOY]

Don,
I don't have all the answers, or know if I'm even right with this one, but, I understand there are actually 3 different D motors. The D motor was a follow up to the B motor. The C motor was a modified B motor with less HP. There is the standard D motor. Monark had a D/GS motor which was a 5 speed with beefed up gearbox. Then there was the D/GS Pro. I've worked on the Pro motor back in the 70's for a Factory Monark rider in Oklahoma. It was really tricked out, porting wise, had the "stuffed" cases and the heavy duty beefed up 5 speed. If I remember correctly, they (Monark) took a thicker cut 5 spped tranny and installed into the "stuffed" cases. Porting included some finger ports and enlarged intake. THe cyclinder had a bolt on carb, not the slide on. The Monark motor we had ran a 34mm bing. They claim that engine produced 24-26 HP. If was very fast for it's time, but ate rods and pistons like it was starving. I remember doing a complete rebuild about 10 times that year.
There are alot of stories out there abot the D motor and mine is just one. Some people say there is no difference between the D and the GS motor. I think that there is alot of differneces. Larry Perkins has had D motors. I've heard that Larry Good has a D motor also. He races in Southern CA. There is a great photo of a GS PRO motor in VMX magazine #14 installed on a Monark. I have a copy of a Sachs Motor-Service Manual that covers the 1251/5A, 1251/5AL. 1251/5B, 1251/6A, 6B, 6C, 6D. Hercules non-exported even had a bike with a 1251/6E motor, which I have the owners manual for, but, it doesn't give any breakdown, just a few specs. I know there are mre folks out there with more info than I have. Like I said, my information may not all be true, but some is "just what I've heard" so don't hold me to any of this.
Donny

[Larry Perkins]

Really not tons of differences between the B, C, and D motors.  The biggest deals I remember is the B had the newer style carb over the A.  The C had a different carb mounting system and bigger inlet over the B.  The D had a different mount for carb.  There were other differences but I think that was the main ones.

The real different one and the one that everybody thinks is the D motor is the D GS motor.  Which had a bigger carb, internal rotor ignition, stuffed cases and crank, milled head, and different porting.  These motors were bulit for the top level shop racers and the factory level guys back in "The Day".  Alot of people think mistakenly that all D motors were like this but not so.  Doug or Paul could shed more light on this than me though.

 

[Larry Perkins]

Looks like while I wrote the above Donny gave even more info than I remembered.  Good job, Donny.

 

[OUCWBOY]

Larry,
I wasn't trying to write a book, but it looks like it. You are so correct on the GS motor. I remember coming to CA in the 70's with our Monark and rider. Monark put all of us together in the pits. The motor on the bike that Tommy (my guy) rode was different than the one that Marty Smith rode and both were differnet from Turner's bike. Marty's was the fastest of the three. (go figure!) There are a few GS motors around, but not many. I've only seen two in the last 3 years.
Donny

[mad max]

HI penton 117
     I once had a works sachs motor fitted to my works saracen m/x they replaced my 6D motor with a 7D/GS motor 7=gears D= model GS=grand sport hope this info helps
           NIGEL.

 

[Cathump]

It's great to have a resource like this group.

The bike in question is mine, and I'm still new to Pentonia, but I can say that when I rode this bike, it felt like it has more power than my '74 Yamaha MX 250.

 

[OUCWBOY]

Mad Max, I only wish that they exported that motor to the US, but I don't think they did. Could you find one for me? I'd love to have one.
Donny

[mad max]

Hey Donny wish I could find one myself I belive it was the only one ever inported into the UK befor saracen motorcycles went bust I cant find a sarscen over here but may be one day ?
       NIGEL.

 

[Dwight Rudder]

My 1974 had a GS engine. I called it a "D" but I believe it was just a modified B engine that had SPECIAL KTM TUNING on side of cases. It was VERY FAST. It had a step up sleeve over spigot so you could put on a 28mm Bing ( similar to the 30-34mm Bings ). It wouldn't rev as high as a standard "B" engine but it got there faster. My GS engine was faster than Tommy P's personal bike in the accelleration tests. But it topped out at 65mph.  I know that many 125 Pentons would top 75-80mph.
Dwight

7 time ISDT / E medalist
7 time National Enduro Class Champion.

[OUCWBOY]

I've just purchased another bike with the GS type motor in it. Hope to have it here in about a week or so.
Donny

[metalkfab]

I'll be bringing my " D " motored Penton to VMD.No it doesn't have stuffed cases,but it does have a different cylinder,carb and a internal rotor Motoplat.Seems as if the pipe is larger in the center section also.The bike also has a different frame,the rear shocks can be positioned at various angles ,Al buehner says he never seen this before but I have a old "Keeping Track" that shows this frame design for 1975 models.

Edited by - metalkfab on 07/16/2002  5:16:06 PM

[Larry Perkins]

The last Sachs motored Pentons that I saw were manufactured in 1975 and were D motored bikes that had a white tank like the Mint 400.  They had the 2 shock positions on the top side.  The one I sold Ted Landers was originally like that when we got it and it was a 1975.  We put the traditional green tank on it.  There is alot Al has not seen like a computer screen-joke joke.

 

[OUCWBOY]

Between all of us here on the POG you'd think we have seen it all. But there is always something that pops up and we all have to really dig deep in that old data bank and still come up with a blank from time to time. Anybod have any idea what that Sachs powered bike on E-Bay really is?

[Larry Perkins]

I think you tagged it, Donny.  I think it is a MOnark enduro without the lights and a homemade forward mount done about 1974 or 1975.  If someone gets it and wants to enduroize it I have the Monark head and tailights as well as a good amount of Monark parts though I am working a deal on the Monark stuff as a whole.  The lights I will still keep.