Sachs Gearbox Adjustments

[jay cohen]

The racing season is almost here, and since I plan on racing my completely restored Six Days for the first time, I was curious about the gearbox adjustments.  I was wondering how often you guys adjust the Sachs gearbox in a normal racing season, let's say if you compete in 6-10 events ?  Is it usually required after every other event, once a season ?  I was reading on the Vintage Monark website in an old magazine article from '73 about the Monark and it stated that if you are serious and run the Sachs in an expert class, that you should do it after every moto !  I thought this was nuts.  But, according to some of the old magazines articles I read, it seems that Monark was much more attentive to the ills of the Sachs box compared with Penton. One of the magazines said that Monark disassembled the Sachs engines once they got them and set them to their own specs at the factory in Sweden, making changes to the gearbox and doing other fine tuning before the bike left the factory.
Did Penton Imports go over the Sachs engines ?

[dkwkid]

They are going to be as good as they can get if you shim the gearbox up tight. Unless you fall and jam or bend something you won't need to adjust that often.
 Lots of people boo-hooed the Koba kits but if you look at pictures of the later German Military Sachs engines the selector arm has a spring on it to achieve the very same thing. The weak link of the Koba kit was grinding angles on the selector key. This weakened the key somewhat. I don't care what the sales people tell you-your Sachs won't shift like a Yamaha or honda.3rd will blow thru 2nd to neutral more often than not

[jay cohen]

Glenn, Not sure what you mean by not that often ? Once a season ?

[dkwkid]

It depends on how you ride it.Once every 6 rides or so. I raced 2 or 3 vintage desert races a year on the Deek and I checked it after 3 years.

[TGTech]

Jay,

The second most critical adjustment in thee Sachs transmissions, is the shimming. If the shimming is not correct, then no matter how accurately you adjust the shifting, the transmission will not shift correctly.

If it is shimmed correctly, adjusted correctly, and SHIFTED correctly, it is impossible to miss a gear. I know this may sound crazy, but I can prove it, because I built demonstration transmissions for dealer schools.

Once the shimming and adjusting is properly done, the shifting procedure is critical. When you shift from one gear to the next, you can not just tap the shifter and hope that it will got into the next gear. You must move the shifter to the end of its travel. Once that is done, the shifter pawl is locked into the shifter quadrant and that prevents the selector rod and key, from going beyond the intended gear. If you just tap the shifter, in either direction, then you can indeed miss a gear.  

Dane

[dkwkid]

there is a word for a trans like that-problematic. In the heat of racing a rider has quite a bit to think about other than making each and every shift positive and complete. Dane, how could you keep a straight face when showing the dealers that it is impossible to miss a shift? I'll bet their customers were not amused!
 It was common knowledge at the time that if you rode a Sachs engined bike you would have to live with marginal shifting.

[TGTech]

dkwkid,

That is not a joke, it is the absolute truth. The way that the shifting mechanism is designed, as long as the shimming, adjustment, and shifing process is proper, it is absolutely impossible to miss a shift.

As far as shifing the engine properly, yes it is something that you have to learn, just like throttle control and braking. But it can be learned.

It was my understanding that the Sachs transmission was never designed to be used for competition, but it ended up there anyway, and then they had to work to make it operate properly.

I didn't understand this, until my Uncle Ted, John's brother, had me build the training transmissions, but I fully stand by it now.

Dane

[sixdazed]

Hi Dane,Is there any info/service bulletins on the training you did for the dealers schools? Thanks,
                                Ric

ric emmal

[TGTech]

Ric,
There was an article in one of the original Keeping Tracks by John Cobb, who was the Service Manager, and that is probably the best article. I don't know if I have it or not, but I'll look and see if I can find it. There is a post of the article on Yahoo under a guy's handle Sachs 175, that shows the article, but the pictures of it are a little hard to see.

I'm going to see if I can find the article and get it posted on the Site somewhere.

Dane

[rcrump1]

Dane;
That would be very helpful to us who are not as familier with the Sachs transmission. One question though, you refer to "shimming" the transmission. Is that something that is done during the adjustment procedure or only when the trans is built (or rebuilt)? If you could clarify I, and I am sure some others, would greatly appreciate it.
Thanks
Richard

[sixdazed]

Thanks Dane,
             Ric


ric emmal