Good morning, Mr. Red;
Interesting that no one has answered your question. And, I also have both the Kiev-88 and the Kiev-88CM.
Your assumption is correct; sending it in for a CLA (Cleaning, Lubrication, and Adjustment) probably will be the best way to restore the Kiev-88 to normal functionality. There can be an adjustment to be made to the gear train portion that works with the second curtain. While I am sure that by now you probably have had the work done, in the future you might consider Stanislav at (
www.mechanicalcamerarepair.com ) who is located in Petersburg, New York. Yes, Gevorg at Arax Foto (
www.araxfoto.com ) is better known, but they are also in Europe. Stanislav used to be in Kiev at Zavod Kyiv (Kiev Arsenal) where he worked in the Photographic Equipment Division for 36 years. You will do well with either one when having work done on your cameras.
Enjoy;
Ralph, Latte Land, Washington