I picked up an old Honda last March that had been sitting unused in an open barn for at least 20 years. While trying to track down any info on the model type, I came across this website and the links to a VIN lookup and the manual, and have been lurking in the background since. What a great resource, thanks to everyone who unknowingly helped me get this bike running and ripping around the deer lease earlier this summer!

The honeymoon has ended, however, and I find myself dealing with the reality of owning a 43 YO machine that, based on the packed oil rotor, was not very well maintained.

I lost spark while in the woods late in September. I was eventually able to get her running again, but not great (I think the problem was water in the connections as drying them and applying dielectric grease resolved the no spark issue). Since then, the bike has been smoking a lot with frequent missing under load. I thought maybe spark or electrical was still an issue, or maybe the CDI was failing. All electrical components check out per the manual, so I threw on a new CDI with no change in symptoms.

Picked up a compression tester and sure enough, dry compression in the mid teens leaping up to mid 150s during wet compression test. Perhaps it was coincidence that I had the spark problem occur at the same time she really started burning oil?

I removed the cylinder and could feel a lip at TDC and the machine shop confirms it needs to be bored.

The question I have is in regard to the connecting rod small end. I have a tiny bit of play between the old wrist pin and the small end. If I push/pull the pin perpendicular to the crankshaft (i.e., in the direction that the piston would be acting on the pin/rod), there is no tangible play. If I "wiggle" the pin (grab the pin between pointer finger and thumb and rotate one the towards/away from the crankshaft) there is a tiny amount of play, enough for me to slip a 0.04mm/0.0015in feeler gauge about 1 to 2 mm into the connecting rod small end. I hope that makes sense.

Based on this, it would seem the small end ID is not a true bore, but it's very slightly fluted on each side. Should there be any perceivable play between the wrist pin and the small end of the rod? Or is this a sign of excessive wear? Oh, the guy at the machine shop mic'd the old wrist pin and said there was no uneven wear on the pin itself.

If some play is expected, I will pick up a set of inside gauges to make sure ID is within service limits. If any amount of play between the small end and pin is unacceptable, I will save the money and put it towards a new crank, case splitter, and bearings

I'm hoping some play is normal as breaking the case and replacing the crankshaft will seriously increase the cost and effort of a top end rebuild!

Thanks