Sachs Shift Adjustment 101 & Koba

[Dale Fisher]

A collection of articles with different approaches to adjustment.

Keeping Track June 1973:





Tricks on Tuning:









Slick Shiftin with a Koba:





1972 Cheney Sachs
1972 Suzuki GT380
1972/73 Cheney Sachs Project
1973 Triumph TR5MX
1973 Penton Jackpiner Project
1974 Penton Berkshire
1974 Honda MT125

[Ron]

Now if we all just had a KOBA Shift Kit!
I'm sure I could reproduce one, if I could find one.
Ron

[BrianTaylor]

Super thks Dale ... yes I would love it as a PDF ... you should have my email ... [email protected]

Brian Taylor

[ccmnova]

quote:Originally posted by Dale Fisher

A collection of articles with different approaches to adjustment.

Keeping Track June 1973:





Tricks on Tuning:









Slick Shiftin with a Koba:





1972 Cheney Sachs
1972 Suzuki GT380
1972/73 Cheney Sachs Project
1973 Triumph TR5MX
1973 Penton Jackpiner Project
1974 Penton Berkshire
1974 Honda MT125

CAN'T OPEN THESE - Can you send them to my email [email protected]

[Larry Perkins]

Koba kits are pretty much non-existant but I will tell you the ultimate Sachs shift secret.  JP Morgan figured out(the wiz that he is) that the reason they shifted bad was they had a slow drop in time and he can; for a charge of course, modify the gears and weld the shift mechanism and make it shift almost like a Jap bike. It is an amazing difference.  Not sure if he still does this but maybe he will chime in.  It is unreal!  Of course, in my book he is an engineering genius!

Larry P

[ccmnova]

I'm in the Pittsburgh area and can bring my bike anywhere within say 4 hours drive - do any of you know a capable shop or mechanic who can do this shifter adjustment procedure for me - ?

[Gordon Brennan]

This information above is a perfect example of the necessity for a separate Discussion Category called "Vintage Tech Reference". cafehusky (Vintage Left Kickers) has a separate one called "Vintage Tech Reference and Parts" because they have parts diagrams of pretty much every Vintage Husky. I use that constantly for my 73 Husky.
I'm not trying to make extra work for anyone. Just set up the heading and users can add stuff like this when they come across it.
Go here to see how Husky does it: http://www.cafehusky.com/forums/vintage-tech-ref-and-parts.66/

[Tonyp884]

How could I get in touch with JP Morgan about this shifting cure that he has developed?

[Dale Fisher]

In some cases I am not confident a series of .pdf manuals would do the trick.  Most if not all are available at the asking or through purchase.  Keep in mind shifting issues baffled quite a number of folks back in the day. We know adjustments were one of the ways dealers augmented low profits on sales.  

In my experience.... in using the adjustment guidelines it takes some experimentation to get things right.  You may have to pull the cover and do some more tweaking to get things were you like them.  Where is that Penton dealer service man when you need one [?]

Dale Fisher
Penton Owners Group - President/Memberships
POG Merchandise
Mudlark Registry
Facebook - Penton Owners Group - Administrator
Facebook - Cheney Racing Group - Administrator

[JP Morgen]

With my last engine build, 6B, I installed a set of my cut gears(selector key openings widened by 4mm), but it still was not shifting well. I have since added a two piece, spring loaded selector arm from the military version engine, which works like the spring loaded selector rod from a Kobe kit, along with the additional, "external" detent mechanism....WOW! Shifts fast, easy, smooth, haven't missed a gear yet, even under racing conditions, and the other bike I rode the same day is a 125 Honda Elsinore, which couldn't be more different. Anyone need more information, etc. I can be found if you search Morgen Machine on Yelp in San Francisco.

[JP Morgen]

More on Sachs shifting.
When I finally understood the engineering and mechanics of a Sachs transmission my conclusion was, "How is it possible even to complete one good shift, ever!" The selector key only has .25mm(.01") clearance in the slot of the gear!! Imagine you are the selector key, you are engaged in a gear, you are spinning at the speed of that gear, the gears on either side of you are spinning at different speeds, it is time to shift, you are pushed or pulled out of the gear you were in and now you have to jump into the slots of the next gear, but it is spinning substantially faster or slower than you were spinning, AND there is only that minute amount of room for you to fit into, and your leading edge is rounded off, even when new! Typically you miss the slot, run into the solid face of the gear, or the edge of the slot, and if the rider has by now stopped pushing up or down on the shift lever, you are sitting in no man's land between two gears. Ok, rider, take a full stomp or pull on the lever now, and guess what!, you are sent through the slots of a gear and into the next "neutral" void between the next two gears, Aarghh!!
Kobe shift kits were two smallish band-aids that helped shifting performance, but didn't address the actual problem: not enough "drop in" time. I was very excited to pull apart a customers motor and find one of the kits inside. I quickly saw why and how they did what they did, but wasn't impressed with the end results.
The slots of the gears can be cut open wider, but not too wide, you will have major problems! I have mine cut using an electrical discharge machining set up. The gears are hardened(very), and because of the shape and orientation of the slots can't be done any other way that I know of. It is not cheap, $350/six gears. You still need to carefully shim and adjust the transmission, but the improvement is huge. One ex-pro who I did a motor for said it shifted 500% better.

[ccmnova]

I'm in the Pittsburgh area and can bring my bike anywhere within say 4 hours drive - do any of you know a capable shop or mechanic who can do this shifter adjustment procedure for me - ?

[desmond197]

I wished some one would do a you tube video of this procedure for every one to view