Scooterotica

hi when i fit the inner bearing on the crank shaft i usually heat it up and it drops on well my new build done 70 mile and the inner has come loose and caused loads of vibration so fitting a new one would you heat it up or tap on cold these are fag high load german bearings

is it a new crank? last couple of cranks (indian) i have fitted you could put the inner race on and off by hand,, is that your problem, the crank is spinning but the race isnt? also if you heat it up too much,, until its blue, you soften the metal and it will wear alarmingly fast

the crank is brand new tameni 57mm full circle race crank on cassa ss200

I use a hot air gun to warm mine up so as not to get it too hot as ive done in past using a flame

Your can overheat it with an air gun too, I've blued one doing that.

I've never had to use heat to install an inner bearing race on the crank.I use a long flat peice of metal that fits in between the webs of the crank,I then put the crank between two points making sure that all the weight is on the peice of metal and drift the inner race onto the crank.

i would suggest have you crank in the freezer overnight, i then use a vice to grip the flywheel side of the crank only, then boil the inner sleeve in water, should slip on with a light tap, if you had a loose sleave i would apply bearing and stud locktite to the crank and inside of the sleeve,and tap home, i have a steel tube thats just the right size that i use, then wipe clean.

rosscla wrote:Your can overheat it with an air gun too, I've blued one doing that.

This is very true. I also stick the crank in the freezer in a sealed bag for a few hours so think this helps aswell.

bazza3004 wrote:

rosscla wrote:Your can overheat it with an air gun too, I've blued one doing that.

This is very true. I also stick the crank in the freezer in a sealed bag for a few hours so think this helps aswell.

+1. Seems a few have learned this particular lesson.

If you're worried about the inner race being a little loose apply some loctite bearing fit.

holty wrote:i would suggest have you crank in the freezer overnight, i then use a vice to grip the flywheel side of the crank only, then boil the inner sleeve in water, should slip on with a light tap, if you had a loose sleave i would apply bearing and stud locktite to the crank and inside of the sleeve,and tap home, i have a steel tube thats just the right size that i use, then wipe clean.

... that's exactly what I do.

Adam