Stripping engine paint

I've seen many pictures of bikes on this site which have bare engines. Is it alright to simply sandblast the engine and crankcase clean and leave it like that because its made of aluminum? If this is what people are doing, is it difficult to do so to an 82 XJ650RJ Seca? Does the engine need to be removed from the frame? And how long does that procedure take?

 

DON'T sandblast! That's for pieces removed from disassembled engines. That stuff gets everywhere, and usually stays there until it can come out and do as much damage as it can! Cases can be stripped with Tal Strip aircraft stripper (safe for aluminum) but needs to be neutralized with water. RickCoMatic did a real nice piece here about polishing aluminum...I could repeat it, but it's already been said.....better. Dig around and see if you can find the thread. Good luck!

 

To do it ~right, you need to pull the engine and have it media blasted with something like baking soda or plastic beads that's easier on things than traditional grit like green sand.

You'll still need to plug and blank all the entry points into the engine. While the softer abrasive media won't kill the engine if a little sneaks in (maybe?), the layers of paint and aluminum oxide blasted loose definitely will....aluminum oxide is used to make sandpaper grit.

For this job, duct tape is not a suitable way to protect your engine's internals!.

Then you get to figure out a way to degrease the 180# lump, followed by paint application as you maneuver said engine without screwing up the new paint. Or screwing up your back.

There's still no guarantee that some gasket won't weep a trace of oil before the paint fully cures, leaving a slender trail to show it's mockery of all your work.

To really do it the right (safe) way, pull the engine apart and have it stripped and painted by a shop. Figure on about $200.00 for gaskets and at least as much for the paint work.

Even better: leave it alone, and think of the weathered paint as patina on a classic bike.

 

A spray can of "mar hyde" Aircraft Aluminum Paint stripper ..works ..V well indeed (any Auto parts store) Spray on ..wait..on spray off with a water hose
You WILL have to do a decent job of masking the bits you want to keep painted though. Quality of the job will depend entirely on your willingness to carefully mask. Beyond that.. it's really easy.
Reverse the process to repaint.. use PJ1.. it s IDENTICAL to yama's paint job.