cleaning my barrels...

[KnowFear]

I've removed the barrels and pistons on '83 LeMans III with @ 20,000 miles. The bores look pretty good and the cross-hatching is still clearly visible. The exteriors of the barrels need a good cleaning to remove oxidation. If I clean them with some mag wheel cleaner (acid-based) will I risk damaging the Nikasil bores?

 

[kiwi dave]

I wouldn't risk it. Perhaps the mag wheel cleaner might wash out the oil impregnated in the bores.

Can't you mask the bores, i.e. seal them off before applying the mag wheel cleaner?

 

[gstallons]

Do you have access to someone that can use baking soda or dry ice to blast them ?

 

[GuzziMoto]

This is a little out there, but we always used Muriatic acid to clean nikasil cylinders of our TZ250. It would dissolve the aluminum stuck to the bore from a seizure without touching the nikasil. I doubt that mag wheel cleaner is going to be an issue. It is made for aluminum wheels. My biggest worry is that it may not be strong enough. Blasting the cylinders may work better but that you would want to take some precautions.

 

[ghezzi]

Regardless of what you clean them with, almost anything will be okay, you still have the same problem from original.
Any un-protected alloy will oxidise and tarnish. Don't use clear coat, it will just go yellow.

After bead blasting or just scrubbing with hard bristle brushes and hot soapy water, I have always sprayed my alloy Guzzi bits with heat proof aluminium engine paint. Years later people comment on how knew my bike looks.
Even after long tours in the rain it can be cleaned properly without that baked on gunge look.

I've done this to an SP1000, a Cali MkII and a Le Mans MKIII when doing engine rebuilds.