My other bike Big End

[guest146]

Has anyone had experience with single cylinder crank alignment after fitting a press in big end assy. My classic Francis Barnett was making some strange noises and upon stripping the motor i find  the generator side big end pin into the crank had moved about 3mm letting the crank rub on the case. I put this on the press in our workshop and pressed it back. For this it needed 2 tonnes. Have spoken to someone that rebuilds these and it seems that pressure is well withing the limits you would expect. Now my question. What limits would be acceptable on checking the crank half's  for true when turned in V blocks.

Thanks Ken

[themoudie]

Aye Ken,

Run out I would suggest should not exceed 0.002" and is best if you can acheive 0.000"! But then others may know better.

On the subject of pressure required to move crank pins, the last Ducati single one I had done required 28 tonnes of pressure to move it! You need adequate support to the crank halves when putting those sorts of force through the pin, to either remove or install them.

My regards, Bill.

[guest146]

Thanks for that.

 Made a V block and will borrow dial gauge and test tom. Had a word with nametab engenerng who spciaise in these and they said 2 tonne is a good fit for one of these.

Cheers Ken