Topic: Refinishing the cases withou disassembly

[ben.cb500]

Hoping someone can point me in the right direction.

Acquired motor and would like to refinish the cases without opening them...

Im open to sandblasting, chem strip or other. Also undecided on finish. Paint or clear over polish or blasted metal?


Any tips and pics appreciated.

[Leroy754]

Sand blasting will remove metal and certainly destroy the exposed edges of gaskets on contact.  Vaqua blasting (sometimes called Aqua blasting) uses water and miniscule glass beads. It will not remove any metal and leaves a robust and almost silver paint like finish.  However, while less abrasive than grit blasting, I can't see how you can keep any blasting medium out of the engine.

I reckon chem strip by hand.

[DustyRags]

I use aircraft stripper and a brass-bristle brush to get some gaskets off this summer. Didn't do a heck of a lot on the gaskets, but left the engine around the gaskets a perfect, clean, dull aluminum. Good luck getting all the stripper off, though- you'll want to wash it well, and that means plugging every possible hole.

[70CB750]

Aircraft striper is a nasty stuff.

[DustyRags]

Yeah, but it works!

I hate to advocate drugs, alcohol, violence, or insanity beastly chemicals to anyone, but they've always worked for me.

-Hunter S. Thompson Some guy on the internet

[BobbyR]

You can sand off the oxide with a palm sander and varying grades of sandpaper. Once you get to the finer papers, you can buff it with a wheel and rouge sold at Sears. People report that clear coatings seem to yellow. Some Mothers polish twice a year maintains the shine.

[ncstatecamp]

How does aircraft stripper effect seals or gaskets?

[DustyRags]

Good point. Negatively, to say the least.

[Tews19]

ben, that's a sweet looking bike you have in the avatar... Have you posted other pics of it?

[ben.cb500]

ben, that's a sweet looking bike you have in the avatar... Have you posted other pics of it?

thanks. [ more pics of my 71 here -> http://www.vfrdiscussion.com/forum/index.php/gallery/member/23797-kc5555/ ]


the original engine is dropping second gear (read that is common), so this new 550 is to swap in so i can ride while I fix it. I would like to get the cases to near original/new looking as possible....appreciate the responses.

I have the cylinders off so its just the lower unit I am trying to clean up, re: strippers, I can avoid seals for the most part.

I dont know the condition of this transmission, it does click through gears ok.

Is splitting the cases just to clean/strip the exterior a bit extreme?

[DustyRags]

I'd say that's up to you, but it seems to me that if you're dropping a gear, and the engine is already out of the bike and torn partly down, it might be worth it to get a nice shine on it.

[mono]

if you don't want to split the cases, there's really only one method available to you:  elbow grease and LOTS of time.   

-- aircraft stripper is evil sh*t, but it works -- not sure what it'd do to a gasket.  test on similar gasket material first.
-- media blasting is out.  you'd get media in the engine for sure.

you can take it apart to clean it and refinish it 100%, or you leave it together and take the "that'll have to do" mentality.  if you're going to ride it, it'll just get dirty again anyways right?   

[DustyRags]

I've used aircraft stripper to get gaskets off- it does bad things to them. Well, if you plan to ever use them again, anyhow. Turns them into a slurry, and then they re-harden into this horrible, caustic cement. Don't get it near gaskets, seals, o-rings, paint, plastic, rubber, or anything other than metal, unless you want it permanently damaged.

[lrutt]

soda blast, won't hurt innerds if it gets in there but you can makesure to protect things. Then either leave natural or silver paint. Degrease things first.