It's a Hercules K105X from 1972 and needs a LOT of work, but I really couldn't say no to the offer. This will probably be my main project for 2026.
It's pretty much complete aside from the missing battery cover and the engine turns over by hand. I had some trouble getting it into neutral, there's definitely something wrong with the gearbox or the linkage. The tank is completely rusted inside, I'll probably need a new one.
It might be a long shot, but does anyone in this community have experience with these bikes? The K125 is supposedly pretty similar.
Nice, you'll find bikes to be away easier to work on than cars haha. Maybe email this guy? https://www.pentonpartsusa.com/catalog/8a%20repair%20sachs.htm
For the tank, I basically turned the tank upside down after taping up the fill port, and reached a bent coat hanger in via the removable petcock, electrically isolated from the tank body with the highest of technology: used chopsticks. Coat hangers usually have a thin plastic varnish, so scrub the wire with steel wool first.
Electrolysis will 'pull' rust from every spot that has line-of-sight with the wire. Considering the u-bend, seems like you may have to do two runs of electrolysis for removing the majority of the rust, then follow it with something like evaporust to get anything that got missed.
Glad to hear you put oil in the cylinder first, I really wish I had known that when I first started haha.
That looks promising, thanks!
The only rust repairs I had to deal with so far were frame and underbody stuff on cars with plenty of space but I'm excited for the challenge. It's definitely a welcome change to be able to work on something while sitting comfortably and not constantly bent over an engine bay or crawling around under a vehicle :D
I really appreciate the advice!