Sachs shifting vodoo curse!

[JP Morgen]

I have built about eight Sachs 6B motors over the years, for friends, for customers, for myself, learned by mistake, by following manuals, and by listening to friendly advice. I just completed my last(probably), for me to race. Shimmed carefully, adjusted carefully, added my cut gears for faster shifting... On the stand it shifts easily and quickly, on the track I am lucky to get in two successful shifts in a row!! This is the worst shifting Sachs 6B I have ever ridden. Over the weekend at the races I spoke with another long time 6B rider who had a very similar experience, but couldn't think of where to look for the problem, so... I am throwing it out there to the POG gang, if you have had a similar experience and can suggest what to look for, it will be greatly appreciated!

[gooddirt]

JP was that Mike B. ?

[Richard]

Well,,,,first, I'm a little uncomfortable giving advice to someone with your well earned reputation, but here goes.

After you miss a shift and then downshift to regain your momentum, are you in the same gear that you were in or in a lower gear? This would tell you if you are overshifting or under shifting. If you downshift and you are in the same gear then you shifted past the chosen gear, adjust your shifter arm a bit to the left. If it's drops down a gear then you didn't move the selector key quite far enough, adjust the selector arm to the right.

I've found that adjusting the selector a balancing act. You can make it shift better upshifting or better downshifting. I try to make upshifting better. My shifting technique (if you can call it that) is to always use the clutch and to hold the shifter lever up as long as I can. But I'm guessing you already know this or you would not have gone to the trouble of cutting the dogs in the gears to improve the chances that the key will find the gear. Downshifting has rarely been a problem as I seem to be able to stand on the shifter longer than I can hold it up.

I hope this helps and I don't sound like I'm all knowing about things Sachs. Far from it, but I do like the little motor from Germany...

[gooddirt]

Had one that I could not get right on the bench, thought it would never shift. But worked 100% on the track.

[Paul Danik]

JP,

    Might start by allowing a bit more clearance between the inside of the side cover and the shift mechanism, and see if there is any noticeable difference. Given your expertise in getting the innards perfect I am wondering if there is a glitch in the shift throw/return.

   Is there any noticeable difference in shifting with, and without the clutch?

   I remember years ago some of the shift mechanisms had flaws where they were pressed together, might take the entire mechanism apart to its basic components and look for any flaws that would allow for an improper relationship between the action of the shifter and the movement in and out of the selector key.

   If you have another shift mechanism handy to swap out with the current one, you might be able to eliminate that entire portion of the shifting equation, or possibly find the issue.

Hope this helps.
Paul

[Mickey Sergeant]

Nice talking to you at Washougal. I have been thinking about our conversation. Shifts you saw me miss are mostly me. When I get excited I short shift and miss shifts. I remember when I had all kinds of problems with my 100 like your having. Would shift great on the bench, but once under power wouldn't shift. I ended up puting a brand new selector boss assembly on and problem went away. I had a good crash in the second 125 moto. Hit one of those kicker bumps  and rear end came up and over over. I think the foot peg got me just below the knee, had a big gouge in leg and swelled up as big as my knee. Couldn't get out of my truck when I got home. Back has been hurting and side of my foot is black and blue. Finally feeling better today, will be ready for rattler run

[JP Morgen]

Get well soon Mickey! I probably won't make it to Rattlers.
Paul, thanks for the tips, as it turns out I put my clutch cover on with no gasket. I can't for the life of me shift with the clutch, especially in a race! I have checked overshift amounts on the stand, and they are pretty equal between all gears, up or down. I will ride around the block this weekend, and try with more clearance, I have a suspicion it is overshifting in the heat of battle. New shift quadrant on its way as well. Thanks all

[SouthRider]

JP - I had a similar problem with my Berkie, and the nut that holds the adjustment for the shift mechanism was slightly loose even though I had tightened it and used the lock tab.

Just a thought on something to check.

There is such a thing as having TOO much adjust-ability - damned Germans......

Clark

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