Slowly but surely... I seem to only be able to free up Sunday afternoons to work on this bike. Made some good progress today, but hit a new obstacle too.
2 bits of advice for the next new guy:
1) If your idler doesn't turn when you tighten it down against it's mount, take it all apart and fully seat the bearing inside the idler. See picture, lightly tap with a hammer where I'm pointing... (Thanks opus!)
2)
Don't mess with bending the coaster arm until you've installed and trued the drive sprocket! Once the sprocket bolts are all tightened down, it may not be necessary to bend the coaster arm for clearance.
I installed the CDI box in front of the engine at a convenient junction of frame tubes. Wired everything up per the Grubee instructions, grounded the kill switch to the engine mount.
My replacement wheels from CustomMotoredBikes.com arrived a couple weeks ago and I finally got them installed today. They seem much sturdier than the stock Huffy wheels and I didn't have to tweak the coaster arm to clear the sprocket. Sprocket installation was relatively easy since I'd already opened up the center hole to clear the dustcap.
I was able to set the drive chain correctly without the idler, and I think the pedal chain is close enough. The pedal chain is a bit looser than I'd like, but if doesn't work out I'll start playing with half-links and use the idler as a last resort.
Thought there would be issues with the clutch, since when I first tested it the rear wheel would still turn over the engine. I had removed the head to pre-oil the engine and was tesing the clutch setup without compression - torquing the head and installing the gapped spark plug gave enough compression to free the clutch plates. Things are working as they should now.
Unforunately, when I installed the shut-off valve in the fuel tank, I found this week's obstacle. The shut-off valve nipple wants to go straight into the frame... Suggestions, anyone? I think I'll have to find another fitting and some sort of in-line valve to get around this.
The throttle cable is way too long... I'll have to disassemble the carb and shorten things up in there. I think it'd run okay as-is, but I know I can't get to full throttle and the first 1/3 of handle twist just takes out slack with no effect on the carb.
The to-do list for next weekend looks like this:
a) resolve fuel line rouing issue & finish plumbing
b) shorten throttle cable & rear brake cable sheath
c) cleanup wire/cable routing
d) modify/install drive chain guard
e) remove tires to install anti-puncture liners & get rear tire turning the correct direction
f) install my $0.99 ebay bicycle computer
g) modify fenders an install
h) ride the darn thing!
g) and h) may not be in that order...
Thanks everyone for all your feedback. Bear with me, this may be the longest new-frame build project in the history of this site but I can see the light at the end of the tunnel...