Sachs 125 Transmission Adjustment

[NYPenton125]

Hi,

 I am in the process of rebuilding my 72 Six Day 125 and need some advice on adjusting the Sachs six speed transmission. (The shoddy shifting of the bike was the reason I began the rebuild in the first place![xx(]) I've disassembled the transmission and made all the adjustments per the OEM manual. At this point, the case is back together and I am attempting to adjust the shift mechanism, but so far have not made much progress...
 Searching the forums I found references to two articles specifically on this topic, "POG Newsletter c.2002" and "Keeping Track June '73, 'How to make the 100 / 125 Pentons shift like a dream' by John Cobb." Does anyone have these articles in print or electronic form? They would be IMMENSELY helpful! Short of that any tips for this adjustment would be welcome.
 Thanks!

Matt Burns

[firstturn]

Matt,
  If someone can't get the article from 1973 to you I will call and go over the adjustment with you.  Give it a day and see if anyone can send it.  If not just click on my ID on the left and send me a phone number where I can call and the best time to reach you.  You'll be teach us how to build engines in no time[8D].

Ron Carbaugh
Kerrville, Texas

[Doug Wilford]

Al Buehner has the special tool needed to get the most possitive adjustment.   It is a must, for proper adjustment.

[Gavin Housh]

Doug, I have had trouble in the past getting the eccentric screw nut tight enough. I have tried an assortment of 10mm open end wrenchs and have not found anything that allows a good solid bite on the nut. I have started taking the two allen screws out that hold the selector shaft assembly down. Then as I slide the selector shaft out, the selector lever will come out with it. Then I take the selector lever to the bench and use a six point 10mm socket to crank the eccentric screw nut tight. Then I reassemble the whole thing and go through the adjustment process of feeling the play in the selector fork to assure that the relationship of the eccentric bolt and the selector lever has not changed from the tightening of the nut. Sometimes I go through this several times until I'm satisfied that I have it right. I have often thought that a threaded hole with a cover (like the clutch cover uses)in the cases that would line up with the eccentric screw would be the best way to modify the engine cases so that the adjustment procedure would be easier and you could just use your six point socket from outside the case to tighten the nut. Have you found an easier way of getting the nut tight enough that it will stay in adjustment longer? Thanks, Gavin Housh.

[TGTech]

Here's the procedure that Uncle Ted taught me: Move the cams on the selector mechanism screws away from the selector pawl when the shifter is moved all the way in either direction. Then when you have the special tool in place, (which is absolutely necessary) and the shimming is done properly, you need to get the transmission to a point where it will shift between second and third gear without moving the clutch shaft or countershaft. Once this is accomplished, when you shift the transmission  from second to third gear, hold the shifter all the way to the extent of it's movement and see if the selector rod actuator fork, has play in it. If it doesn't, then shift the transmission back to second gear and hold the shifter all the way down, and see if the fork has play. If the fork does not have play in either direction, then you have to replace the selector plate that holds the shifter mechanism to the cases. If there is play in one direction but not in the other, you have to make the adjustment to a point where there is play in both directions. Once this has been achieved, the transmission is adjusted properly. When this is done, move the shifter all the way in one direction, hold it there and loosen the screw holding the cam and slector plate to the cases, and move the cam tighly up against the selector pawl. This task almost takes three hands, but it can be done by two. Make absolutely sure, that the shifter is all the way to the extent of its movement. Once the cam is tight against the pawl, then tighten the screw. Then move the shifter all the way the other way, and do the same process. Once this is completed, the transmission should shift perfectly.

Dane

[thrownchain]

Hey NYPenton125, what part of the state are you in??

[NYPenton125]

Thanks for all the advice! Ron, I may take you up on your offer for "tech support". Dane, I'll try your steps and see if that does it. Seems I really do need that jig from Al to hold the shift mechanism in place (been using the case as a "jig"). Should have some time this weekend to look at it again, I'll post the outcome after that!
Thrownchain, I'm in the Capital District, so I hope to have the bike up and running soon before the snow starts to fly!



Matt Burns

[Doug Wilford]

In reply to Gavin.   I made a wrench to fit the 10mm nut with the tranny in second gear.    The wrench I started with looked like a Tappit wrench, (thin) then all I had to do was grind the edges of the wrench so it would have some clearance to move once on the nut.   Good luck and Have fun.
Doug

[john durrill]

Matt,
 We have a library on Yahoo with that info, but you can follow this link and look in photos under sachs tranny adjustment. Its an article by John Cobb from Penton Imports. It should help you a lot. Save it and print it.
  http://profiles.yahoo.com/sachs175
John D.

[bentrims]

Good stuff John. Thanks for the library info.
TB

[Lew Mayer]

First, sacrifice a virgin to the Sachs Transmssion Gods before attempting ANY adjustment.[)]

Lew Mayer

[NYPenton125]

Thanks for the link John! With it and all the advice from this thread, I should be able to get the transmission in order. Hopefully the Sachs Transmission Gods will be merciful!

Matt Burns

[bentrims]

Yeah Lew it make take a few times to get that adjustment down.

[OUCWBOY]

Don't forget that after you complete the adjustments, keep space between the shifter and the clutch cover.

Donny Smith
Paragould, AR

[Doug Wilford]

The shifter assy. should be shimmed on a plane, level with the cases.   The side cover is on the same plane, level with the side cover.   That is why you need to make sure the shifter assy. is shimmed correctly before using the transmission adjustment tool.  Good point Donny, if it is to tight a fit or to loose is does screw up things.