I have read through many of the post regarding sandblasting, all seem to refer to frames and other frame/body parts. I plan to do so with mine to. I wish to take it a bit farther and this is what I was hoping to find but could not.... sand or soda blasting the motor. I have seen post/videos online about it, but has anybody here have any experience having that done with their motor? I have it almost ready, but a lot more to get ready for the rest of the frame and other parts that were attached.
I will edit later adding some pics of the prepped motor.
 

For the aluminum parts I have a local shop vapor hone them if they are really corroded. This also gets the clearcoat off of the lower fork tubes, wheel hubs, brake backing plates, cylinder heads and crankcase covers. Then some polishing with a variable speed Jet buffer. I run it at 900 rpm. Final step is with a cotton wheel and white compound. There are varying degrees you can take it from the "semi gloss" the factory did all the way up to mirror like finish. 

The factory painted the lower fork tubes and case covers for the '68 and for some models into the later years.

Yes I soda blast my motor and cases and wheel hubs not any issues getting ready next week to start restoring my AT2 I have a friend that has a vapor blasting cabinet about 20 miles away so I might try some parts and see how it compares to soda blasting 

Its been many years, but I got great results with a guy who had a hot water/Steam blast type cabinete on a Mach 3 engine I was doing at the time. I would use this system again if I needed to do a motor today.

All great info, thanks guys. I should have mentioned the whole game plan I had. I am planning on, at least for the time, to do a restoration. It may be a full one, looks wise. I need to mention, this is the 1973 MX250 I got running this year after it sat for 35 years. The rebuild can be followed on "73 MX250 Fixer Upper- Part 2". All of this is surrounding the tank I trashed out. I got this yellow tank off eBay to replace the original. I feel that really needs to match the year of the bike color and decal wise. If I do that, as in paint the tank, then this nice shiny new looking tank will look out of place on the rusted frame it sets on now. If I paint the frame all new looking, then all the screws, nuts and bolts will be out of place since the chrome and zinc plated fasteners are all rusted and will be an eyesore.

So that’s the backdrop. It will be from the ground up “clean up” of the bike. I will do what I can to make the rims look like they have zero miles, the spokes I will not replace, but clean them of rust and maybe seal coat everything once they are all cleaned up to looking nice again. I would really love to change out the spokes and I have done this on bicycles, but to remove the tires again and reinstall is more than I want to get into. I would like some feedback on this plan. Thanks, HT1kid for the confirmation on the soda blasting for this part and it will be for the motor too. It’s painted black from the factory along with the carb, but a lot of paint is missing from both.The lower tubes are aluminum finish, and the soda blaster will be the thing for them too. The upper tubes are in great shape and will not need anything done to them. The plan again for everything is to get as close to original as practical. So, if the lower tubes are semi-gloss and clear coated that is what I will go for. Thanks, 1971DT250 for the info. About the vapor blasting, I seen a video on it just now and I see there is a lot of water involved. If my motor was disassembled that would work, but I just rebuilt it and was planning on prepping and painting it all in one piece with the intake and exhaust blocked. The rims and hubs were going to be done hopefully the same way I ran the axle through all the components and added a spacer to take up the extra slack made by the rear forks and the lower tubes not being there. That way all the new bearings and grease will not be contaminated, so I hope. If the axles ends are chromed, I will re-chrome them, if they are zinc plated, I will do that then, I think they are chromed, but would love confirmation on this along with any other certainties about nut and bolt (screws too!!) finishes. The chrome work I will send out, the zinc plating I see is very simple, and will try that myself.All this will also give me the opportunity to get a new brake pedal backstop welded back on since the original departed. Also I seen a hole worn in the lower rail were the bike must have been laid down pretty hard, often enough to wear a hole about the size of a dime in one of the cradle tubes.

@Crazy Horse 124, the steam cleaner, might that have been a vapor blaster? The video I seen it did a great job of cleaning fast, and it did look like it could have been steam, or at least a lot of water mist.

@1971DT250, I don’t think the lower tubes or hubs have any clear coat left on them, but would love to know would a buffing bonnet for a drill do the polishing needed to get them to a semi gloss sheen? Or would I need to be more aggressive?I would love to add pics but it seems I cannot at this time. I have tried yesterday, and just now, but it is a no go.