Finally finished putting the 28cc McCulloch on the old Schwinn Continental. After pulling a Mac 2816 weed wacker out of someone's trash a few years ago, I left it in the corner of the garage until about a month ago. I got it running, but the compression seemed like it might be a little weak, so I took it all apart (which I would probably have done anyway).
Some of the things that got done on it:
Cleaned all deposits from piston/cylinder (was hardly any).
Got a new ring from Frank Bowman. TIGHT fit - virtually no gap.
Trimmed flywheel fins - removed starter pawls.
Flipped carb over so the choke and mixture screws are where you can get at them. But this made more mods necessary.
Fabbed an adjustable choke lever.
Also made a new throttle lever - the tiny metal "tab" on the carb throttle shaft.
Bend in fuel line would have been too tight, so I made a plastic elbow.
New fuel lines and filter.
Aluminum spindle that fits over shaft and is tapped for threads by flywheel. Spindle is 5/8 OD for drive rollers and outboard bearing.
Tapped square hole in end of shaft for fine thread, hi-grade bolt. This prevents the spindle from screwing off when bump starting.
Made new outboard bearing holder/roller guard.
Steel plate for mounting.
Two tension spring holders. Each one pivots and holds two springs. When I had one tight spring on each side, I'd go through a few springs a year. Using two springs that aren't stretched as much solved that problem.
Cut all new gaskets. I even used real gasket paper this time. When I rebuilt my Homelite, I used the cardboard from a case of Old Milwaukee. You could see the Old Mil label on the intake gasket. Those gaskets worked fine (but I'd still recommend the real stuff).
Made throttle cable so it's easy to adjust, and can be taken on and off without having to re-adjust.
Etc... You get the idea.
It's a bump-start friction drive. So I pedalled up to about 10mph, dropped the motor, and she fired up. Had to fiddle with the choke for a bit, of course. I also was adjusting the high mixture screw. I was able to do this while riding because I have a brass tab soldered in the screw slot. That is, It WAS soldered in the slot. Popped off and fell out of my fingers. By then I had it adjusted pretty good anyways. So I was taking it kinda easy to break in the new ring and listen for anything amiss.
Well, she runs great! It's already faster than my old Homey, and I'm sure it will get a little stronger as it breaks in. I know it was getting around 30mph. Someday I'll have to check it with GPS (I don't have).
I was going to take more pictures during the build, but that didn't happen. I'll shoot and post some of the finished product. Someday. I'm tired.
Some of the things that got done on it:
Cleaned all deposits from piston/cylinder (was hardly any).
Got a new ring from Frank Bowman. TIGHT fit - virtually no gap.
Trimmed flywheel fins - removed starter pawls.
Flipped carb over so the choke and mixture screws are where you can get at them. But this made more mods necessary.
Fabbed an adjustable choke lever.
Also made a new throttle lever - the tiny metal "tab" on the carb throttle shaft.
Bend in fuel line would have been too tight, so I made a plastic elbow.
New fuel lines and filter.
Aluminum spindle that fits over shaft and is tapped for threads by flywheel. Spindle is 5/8 OD for drive rollers and outboard bearing.
Tapped square hole in end of shaft for fine thread, hi-grade bolt. This prevents the spindle from screwing off when bump starting.
Made new outboard bearing holder/roller guard.
Steel plate for mounting.
Two tension spring holders. Each one pivots and holds two springs. When I had one tight spring on each side, I'd go through a few springs a year. Using two springs that aren't stretched as much solved that problem.
Cut all new gaskets. I even used real gasket paper this time. When I rebuilt my Homelite, I used the cardboard from a case of Old Milwaukee. You could see the Old Mil label on the intake gasket. Those gaskets worked fine (but I'd still recommend the real stuff).
Made throttle cable so it's easy to adjust, and can be taken on and off without having to re-adjust.
Etc... You get the idea.
It's a bump-start friction drive. So I pedalled up to about 10mph, dropped the motor, and she fired up. Had to fiddle with the choke for a bit, of course. I also was adjusting the high mixture screw. I was able to do this while riding because I have a brass tab soldered in the screw slot. That is, It WAS soldered in the slot. Popped off and fell out of my fingers. By then I had it adjusted pretty good anyways. So I was taking it kinda easy to break in the new ring and listen for anything amiss.
Well, she runs great! It's already faster than my old Homey, and I'm sure it will get a little stronger as it breaks in. I know it was getting around 30mph. Someday I'll have to check it with GPS (I don't have).
I was going to take more pictures during the build, but that didn't happen. I'll shoot and post some of the finished product. Someday. I'm tired.