Crankshaft endfloat - 175TS

[George]

Hi Ian, the key takes the load and the nut tightens gear on to the shaft and does not effect crankshaft end float.
The key should be a light push fit in shaft keyway and the gear should be able push on with fingers with no side play. I would think that you should fit a new key. If keyway is worn You might have to make a stepped key.
If I remember correctly the bottom vertical bearings are held in place with suitable shims between bevel shaft top bearing and alli clamp that fits on crankcase. Good luck, sure you will sort it out.

[blethermaskite]

Ian, because you have had outside std. tolerance end float on the crankshaft the bottom bevels will have been trying to control the float resulting in more than normal pressures on the bottom bevel bearing pack, so I wouldn't be surprised if you have a little more than expected vertical movement of the bottom bevel ..........once you have the crank endfloat sorted its just a re shim of the bottom bevels to get things back to rights.
Cheers,
George

[ranton_rambler]

Ian, because you have had outside std. tolerance end float on the crankshaft the bottom bevels will have been trying to control the float resulting in more than normal pressures on the bottom bevel bearing pack, so I wouldn't be surprised if you have a little more than expected vertical movement of the bottom bevel ..........once you have the crank endfloat sorted its just a re shim of the bottom bevels to get things back to rights.
Cheers,
George

Yes, I did wonder about that. The extra play from the crankshaft shims giving way (if that is the cause) will have let the bottom bevels come harder into mesh than intended.
Cases are not apart yet so will find out more when that's done.
I made a schoolboy error in not loosening the sprocket nut so may have to throw a few bits back on so I can hold it still.

[ranton_rambler]

Hi Ian, the key takes the load and the nut tightens gear on to the shaft and does not effect crankshaft end float.
The key should be a light push fit in shaft keyway and the gear should be able push on with fingers with no side play. I would think that you should fit a new key. If keyway is worn You might have to make a stepped key.
If I remember correctly the bottom vertical bearings are held in place with suitable shims between bevel shaft top bearing and alli clamp that fits on crankcase. Good luck, sure you will sort it out.

Absolutely - the key is damaged. As far as I can recall it was a new key when I built it, so it's a bit surprising that it hasn't survived better. I will need to look at my notes.
I will have a closer look at the keyway slot in the shaft when it's out. The slot in the gear looks good.

[blethermaskite]

The extra loading on the crank end bevel gear is why the key is damaged.
Cheers,
George

[ranton_rambler]

Split the cases today - a couple of photos attached.
The shims are a bit distorted on the ID, but there is not much of a radius where the main bearing journal runs into the flywheel. There is a bit of a machining step where I could imagine the shim "hanging" up a bit.
Is there a recommended way to relieve the inner edge of the shim? I was thinking of a quick run round with a small fine file to knock the corner off.

IMG_5475.JPG

IMG_5472.JPG

[blethermaskite]

I would use a dremel with a little sanding drum.
Cheers,
George

[themoudie]

As per George (80 grit) and give it a thorough clean with brake cleaner afterwards.

Good health, Bill

[Jordan]

If there's no thicker shim washer (with radius) to place next to the crank web, could shims be placed on the other side of the bearing instead?

[blethermaskite]

Probably......if I remember correctly that's the way Velocette did it, however the problem with this is the need to remove the main bearing from the case several times to get endfloat correct which has the potential to damage the case, its got to be easier just to shim the crank?
Cheers,
George