carb sync again (and a hole in gas tank)

[hannibal]

Last fall I tried to vacuum sync the carbs on the bike and couldn't get a reading on my Carbtune. Though it idled smoothly and sounded good, the exhaust on cylinders 1 and 2 stayed cold so I tried to open up the carb slides. I ran out of adjustment, starting closing the other slides, and totally lost my baseline. I pulled the carbs off to bench sync again and now I'm ready to put them back on and try syncing again.

The carbs were cleaned according to the guide on BassCliff's site (disassembled, dipped in Berrymans for 24 hrs, passages cleaned with carb cleaner followed by air). New O rings in carbs and carb boots. Air/mixture screws are set to 1 1/4 turns from lightly seated. Fuel screws are at 7/8 from lightly seated. I have K&N pods with stock 4 into 2 exhaust.

Valves have been adjusted, points replaced and gapped, and timing set. I also trimmed a bit of the HT leads before it got cold and I need to recheck secondary resistance. I never checked primary cause I was afraid to disturb the epoxy covering the terminal.

I bought the bike last summer and it ran "decently". The positive lead melted off the battery which lead me to this site and all the maintenance mentioned above. I have not looked at the exhaust so I will check for leaks as it warms up. Do you just feel with your hand at the head and around the joints?

Please take a look at these pics. Yes, number 1 is dented on the top left of the inlet.
carbs1.jpg

[hannibal]

Engine side
carbs2.jpg

[hannibal]

I tried cleaning rust out of the tank with vinegar. The first time I left the vinegar in for 2 or 3 days. The bike wasn't running so the tank sat and developed flash rust (I guess). Bought more vinegar and left it in for about 4 weeks. Somewhere in that last week, the vineagr ate through the tank and gave me two little holes, one on each front seam.

gas tank hole.jpg


I searched and found lots of suggestions. Once I get the carbs synced, I'll tackle the tank. I'm planning on cleaning with rust remover, lining with Caswell tank liner, and patching the hole from the outside with plumber's epoxy/putty. Good plan?


What do you guys suggest for rust remover? I've seen recommendations for Metal Rescue, and EvapoRust, and Prep & Etch. I'd prefer to stay away from Prep & Etch since I have a losing record using acids.

[Guest]

Too bad about the tank, some people on here have had success with bronzing but it's a lot of work. I've patched a couple of pin holes with JB weld and they're still holding 4 yrs later, I doubt plumbers putty is gas resistant. With testing the primary on your coils your don't need to disturb the epoxy, your testing spots are the leads coming from the coils (orange/white and a black wire on one coil and a white on the other if I remember right). If a couple of cylinders are firing it's either gas, air or electrics. When you're synching the carbs make sure you have the idle at 2500 or so and a fan in front of the bike.

[hannibal]

Thanks for the advice on JB weld. I'll look into that. Because my bad cylinders are 1 and 2, I don't think it's a coil issue. I'll probably redip the carbs this week to make sure they're clean before I try to sync again. I read something last week about a old fuel line leaving rubber bits in the carbs and causing dead cylinders so I want to make sure that's not my issue.

Not sure where you're saying to test on the coils but it's been a few months since I've looked at the bike.