Honda C90 '89 piston & barrel change

After a week or so being used as a daily ride to work, it was obvious that there must be some wear somewhere as the exhaust had more than a hint of two-stroke & too much oil was being used... We happened to have another barrel & piston which looked to be pretty good so we decided to swap them over & see if that cured the problem....

An hour or so later & it was running again... minus the smoke this time so hopefully its cured that problem?

Honda C90 '89

This has been an on-going project for a year or so since it was acquired along with a car full of assorted classic C90 parts. Insured & ready for MOT...

Honda C90

The blue one... having thought about this on-and-off all week, I can only assume that the wear on the hole in the frame through which the bolt passes is the result of the nut being loose at some point in its past, possibly made worse by the chain being too tight? However on these bikes the front end of the swing arm is rubber bushed, all the boilt has to do is hold it all together (including the exhaust pipe bracket). It doesnt act as a pivot, the rotational movement of the swing arm is allowed for the the flex in the rubber bushings.

Going back together... come to think of it this would explain why the rear wheel has always been mis-alligned in the frame?

Honda C90

There are two of these, both later 12v 85cc bikes. The red one is an  '88 electric start & is almost ready for its MOT. The blue one is in daily use, or was, & is a later bike, '99. It's Krys' ride to work, until today, that is, when I noticed that the rear swing arm pivot was quite badly worn, the pivot bolt was difficult to remove, when it finally came out, we saw how badly the hole in the frame had worn. Particularly, on the left side, where it was worn oval... an over-tight chain at some point in the past, perhaps? Not quite sure how we're going to sort that out but I'm sure we'll think of something!