r75/5 soda blasting

I worked on the R75/5 this weekend so I could get it ready for the trip back to WI. I wanted to get everything in order so that I could have confidence that it would make the journey. I started with carb rebuild utilizing the kits I got from Motorwest. My Dad had rigged up a makeshift gravity feed soda blaster before I got down to IL. He told me on the phone that it worked great and that I was going to have to try it out; sure enough it worked like a charm. The baking soda that I used is just standard stuff from the grocery store (unlike the industrial stuff that you can get), but it still worked really well. The great thing is that it doesn't texture the aluminum and just leaves it looking like it would have from the factory. You can even blast the interiors of the carbs as the soda just breaks down as it hits the surface and then you can blow it out of the passage ways with air or brake cleaner. By the way, brake cleaner is much better for carbs than carb cleaner as it's better for the rubber o rings and seals in the carbs. I also blasted the airbox covers and I may have to do the whole engine on my r75/5 sometime in the future as it just leaves the aluminum looking so clean and stain free (just keep the soda away from painted surfaces because it will attack it as well). You can simply rinse it away though unlike sand which gets into everything. The soda cleaning method beats my old technique (see last picture above)( (Jill likes it better too!).

I've already decided to create a dedicated tabletop sodablast cabinet just for this type of small part blasting. Once I got the carbs cleaned and reassembled I bolted them on and gave the starter a stab. The bike started but ran erratically. I found out that the stock red painted liner inside the fuel tank was peeling away inside and some of the junk had gotten past the tank filters and into the carbs. I disassembled the carbs again, cleaned and reassembled them and then soaked the interior of the tank in hot TSP water followed by a power washer rinse, TSP bath, and final powerwash rinse. The majority of the liner had been washed away, and the steel looked to be in really great shape with no rust inside. After cleaning the carbs, installing the old points (since the new ones didn't work; the scrubber block was too thick and didn't allow for proper adjustment), making some adjustments to the chokes, greasing the ignition auto advance, installing some external fuel filters, and setting the timing, I was able to get the bike to settle into a good idle. It ran out well and I was able to take it for several test runs to the neighboring town. It ran incredibly smooth and the tranny was noticeably tighter than my old r60/5.