OzVMX Forum

Clubroom => Tech Talk => Topic started by: oldyzman on May 12, 2015, 09:49:06 pm

Title: New after market fork inner tubes preparation before assembly
Post by: oldyzman on May 12, 2015, 09:49:06 pm

Gday,
A mate has some new fork inner tubes to fit to his kawasaki, They seem very shiny. Should i run them in the lathe giving them a scuff of fine scotchbrite? Or? 

Title: Re: New after market fork inner tubes preparation before assembly
Post by: Momus on May 12, 2015, 10:31:50 pm

I've just had some stanchions  in the lathe going from 800 to 3000 grit to get them smooth and shiny for less friction and better seal life..


I'd leave them shiny.

Title: Re: New after market fork inner tubes preparation before assembly
Post by: oldyzman on May 15, 2015, 10:40:53 pm

yep,seems shiney but seems like it needs something else. just something not right about it? I am usually happy to leave well enough alone...

Title: Re: New after market fork inner tubes preparation before assembly
Post by: Momus on May 16, 2015, 01:45:47 am

I know what you mean. You can have shiny but a relatively rough surface.

You want very smooth and flat and shiny....

Title: Re: New after market fork inner tubes preparation before assembly
Post by: crs-and-rms on May 16, 2015, 08:38:41 am

you want the chrome legs  cross hatched like a cylinder less friction , smooth equals more friction

Title: Re: New after market fork inner tubes preparation before assembly
Post by: oldyzman on May 16, 2015, 10:12:55 pm

crs and rms
yep, the cross can hold a bit of oil too, me thinks

momus
agree too, want it flat also...

so use maybe 1500 the 3000 with some oil.....

Title: Re: New after market fork inner tubes preparation before assembly
Post by: Momus on May 17, 2015, 12:43:23 am

Smooth equals less friction- surface asperities cause friction...

Hard chrome, properly fine ground, has a very shiny appearance and a very low Ra but is also lubricious because it has a microscopically cracked surface. 

 

Title: Re: New after market fork inner tubes preparation before assembly
Post by: fred99999au on May 17, 2015, 06:45:23 pm

So, on a similar bent (perhaps not the right term for fork legs, however) I am doing the forks for my IT200, but using the original stanchions with new seals and bushings, should I be doing anything other than cleaning them well and fitting them?

I have one leg chucked up the the lathe at the moment and need to get a bigger live center to secure it, but I was planning on using a fine paint cutting compound to clean the surface and then maybe a metal polish.

The stanchions seem largely nick free but have been up and down a few times by the looks.

Title: Re: New after market fork inner tubes preparation before assembly
Post by: Momus on May 17, 2015, 11:19:12 pm

Paint cutters is probably too fine for weathered legs. Start with  800 or 1000 grit wet and dry and soapy water and go up to 1500 or so.

I did this with some CR125 legs after straightening and despite plenty of rust pits the seals are behaving quite well.


You are in no danger what so ever of stripping the chrome from the legs ;)