Sachs 125 layshaft bearing mag side/ crank endplay

[t20sl]

My manual talks about a washer underneath the layshaft bearing on the mag side engine case.  When I removed this bearing there is nothing under it.  Does anyone know the thickness or purpose?  I checked another old case I have and there was no washer in it either.  Also can the end play on the crankshaft/ crankcase be checked by dry assembling and then checking with dial indicator?  thanks, Ted

[Kip Kern]

Ted
The washer mentioned is a strange sort.  It kinda looks like a spring steel, solid washer with a tiny hole in the center, sometimes cut off on a end and sometimes with a "notch" on the end.  You can see this washer if you look down into the center of the bearing and you should see the lube hole.  The purpose, my view, serves as a "spring" load, bearing lubricator, if you will, on the lay shaft end.  Once the cases are assembled, push in on the end of the layshaft and you will notice a little axial play, book states permissible .004 but I go .005-.008.  Remember, the clutch assy is bolted to the other end of this shaft so it is very important to have the washer and proper axial play.  Also, put 700cc of oil in the cases as this extra 100cc will allow proper/better lubrication of the very important lay shaft end.  You need one of the cool Penton inside bearing pullers to remove the bearing mentioned and Al has those.  To see photos of the washer, check out a M427 Clymer shop manual as it provides photos and an explanation of this item. Yes, it is a good idea to "dry fit" the cases , as you have to check end play on 4 Sachs shafts.  I have built many Sachs and have only had all 4 shafts come out within tolerance on 1 or two engines the very first go. Most often, you will open and close the cases two or three times to get it correct.  The key to any engine rebuilding is to remove all of the outer covers and clutches and gears and get the bottom end down to the basics, then check all shaft end play before opening the cases, make notes, then split the cases and make corrections, if needed.  It will make the job a lot easier and you may not even have to reshim anything again, just replace seals and gaskets.  Hope this helps;)

[Gavin Housh]

Ted, I've found that when checking end play on the crank it's almost impossible to get an accurate measurment with the outer bearing that sits behind the crank gear still installed in the case. Also getting the crank right takes patience. The trick is to use the same amount of spacers behind both sides of the crank bearings. The problem is that to add or remove spacers you need a special bearing race remover. Then to put the race back on the crank you need to put it in your oven at 200 until it will slip back on the crank. In doing this you must make shure the race is seated all the way down tight against the spacers. Also you need to be carefull not to mix up bearings and races. These bearings are sold as a set and should not be mixed up. If your working with old bearings make shure you don't mix up sides, and when you take the inner races off the crank put them back on the way they came off. These bearing races have M20 stamped on the edge of the race. Look for the M20 before you pull the race off. If you don't see it then it's on the other side. Reasemble it the same way. Sorry to be so redundent. If building a new engine with new bearings and such, you will also need to have an asortment of crank shims on hand. Otherwise you'll be calling Alan to send you some. This problem becomes worse if you've had work done on the crank, such as a new rod. Reason being that it's almost impossible for the machine shop to end up with the right clearance on the rod and end up with exactly the same width across the flywheels that you had before the crank was disasembled. Many folks just send the motor to one of the guys listed on this site to have this work done. They have the right tools and the knowledge to get it right. That's not to say you can't do it yourself. Just take your time, and if you get stuck write back to the POG site. Good luck.

[john durrill]

Ted,
Jake still has some of the inner bearing pullers. They are a very special tool. It would be worth it for you to get one. To have one made would cost several hundred dollars.
 Its a tool you will need if you keep your bike for any length of time.
 Most times you will end up with the need to shim one side of the crank more than the other to get the clearance right. Remember always put the extra shim, shims on the clutch side of the crank. You can run the risk of haveing the motoplat flywheel contact the triger on the stator or the stator its self other wise. that would be the end of the ignition.
John D.

[t20sl]

Thanks for the help.  I have ordered special washer plus a selection of shims.  I have all the Sachs special tools and bearing pullers as I saved all the Penton tools from when my dad was a Penton dealer.