6B crank end play question

[Grunbay]

I am new to the forum. I've lurked around during most of my project waiting to get the go ahead from the registrar. Finally, I'm in!

With the shims I have, I can get my crank end play down to .008". Is that good enough?

My other choice is to bring it down to 0.8mm - a bit tighter than the .10mm stated in the manual.

I assume that a tad loose is better than a tad tight - right?

I've gotten my other shafts to play nice!

As an enforced lurker for over two months, I have to say that this forum is truly a jewel!

You folks are terrific.

[Ernie Phillips]

Gunbay,  Welcome to the POG.

Remember, you are dealing with angular contact bearings - too much endplay causes excessive radial play.  "A tad loose" is no good for a rebuilt motor IMO.  Too much trouble to rebuild one and not get it right.

I think you might have missed a "0" in reporting 0.8mm end play.    Don't you mean 0.08mm endplay. (0.08mm*0.039in/mm=0.003in).  I think you should be OK, but don't build your engine on my word.  Doug? Kip?



Ernie P.
Chattanooga, TN

[Grunbay]

You're right, 0.08mm is what I get.

Sorry, I have a standard depth gauge and a metric standard!

John T. Gurley
Falmouth Maine

[Kip Kern]

(Sachs) Book indicates .004 per shaft and I will go .005/.oo6 Max in some cases.  Sometimes you have to open and close the cases several times to get the 4 shafts close.  It can happen the first time or in some cases (no pun) as many as 6 times on certain engines:(.  I get them as close as possible but won't fret over 1 or 2 thousands.  They will loosen over time anyway.  Key is, don't get them too tight as this will burn up bearings and shafts (blue coloring).  Have fun!

PS: Don't forget 700 cc of engine oil VS 600cc.  Keeps the Layshaft right end oiled

[JP Morgen]

On the Sachs and KTM motors I try to get the crankshaft end float as close to zero as possible, .001-.002" OK, make sure it feels free with no binding. Trial assemble without the seals for a better feel. I have a KTM manual that incorrectly lists the float at something like.008"!

[Grunbay]

Coming from an OSSA background, I separately assembled the cases with one shaft at a time for the purpose of checking end play with a dial indicator. That whole business of measuring the depth of the casing was too fastidious for my shaky middle-aged hands!

Thanks for the help.

John T. Gurley
Falmouth Maine