I bought my MC21 in 2001 with 12k km. The mechanic said it was in good shape. Basically I just kept it filled with 2 stroke oil, checked the chain and brakes, and put about 3k km on it over the next 4 years.

Due to a move (and the missing license), the bike then sat unused, covered outside for about 3 years. After sorting the license, I started the bike up last summer (after 3-4 kicks), and put about another 1k km on it.

Decided that it was time to do some maintenance and found the plastic gears in the rc valve servo motor were stripped. Then opened the airbox and found that there was not much left of the original filter, with some pieces of it in the carbs.

So, time to pull and clean the carbs. After removing the reed cages, I looked down in at the crank, and found that the furthest to the right side is shiny, while towards the left, it appears brown. See the picture here:

http://xn--qckst9n.com/

I have no idea if the top or bottom end has been touched before,
but am planning to pull the cylinders and do a top end rebuild. I searched some posts about crank condition and am now concerned I might need to do the bottom end too. I will pull the flywheel cover and see if there is play in the left bearing. As the bike was starting within a handful of kicks, and seemed to be running "fine", I want to avoid the bottom end for now if possible. Looking at the photo, does anyone have any ideas about the condition of the crank?