Best option to rebuild PD50Bs

[CB650CPastor]

I'm rebuilding my 1980 PD50B carbs. The -010 buna o-ring for the fuel rails are ok, but not very tight. I found some I like better in my Harbor Freight Nitrile kit. They are just a little tighter. The 007 for the accelerator pump tubes... Not even close. WAY too big. I did some measurements and ordered some 005. Something I discovered in my search is that not all o-rings of a given dash number are exactly the same size. Interesting. I measured the diameter and the width of the groove in the tube, then I measured the diameter of the hole in the carb where the tube gets inserted and ordered accordingly. I'll let you know how/whether they fit.

[CB650CPastor]

Ok. Well, I got through it, but it wasn't pretty. The -010 size that I ordered for the fuel rails (joint tubes) fit just fine, but the -010 size in my harbor freight viton kit were a little tighter, so I used those. This is the kit:


The accelerator pump rail was another story. Nothing seemed to fit. The suggested -007 was WAY too big. (Maybe that fits the 81 with the bigger tubes?) With the measurements that I took, the 005 was as close as I could get. I got the -005 from this kit:


Unfortunately, they were still too big to fit in the carb when placed around the accelerator pump joint tubes. I had a couple of extra tubes, so I put the o-ring on the tube and then spun the tube in my drill while I sanded the O.D. until I got them to fit just right. The sanding process:


Before and after sanding:


Finished!


After that, I installed them and sync'ed them up. Here's my favorite sync tool - the Morgan Carbtune Pro - it uses 4 stainless steel slugs in clear plastic tubes. No fluid:


That's it. I'm very happy with how it's running and I have no leaks! By the way, I found the rebuild kits on eBay. It was around 50 dollars for the four kits total and they came from Japan in about 6 days. Here's a pic of the kits:


The slide needles have multiple grooves, but the middle groove is equal to stock. Luckily, my cut-off valves were all in nice shape, so I just cleaned those up and re-installed them.

[Folsoml]

Sweet!