Ace 90 conundrum

[matt glascock]

Hey all, Here's the current scoop. '66 Ace 90. Engine recently overhauled with new seals, bearings, new piston/rings on a fresh 2nd overbore. Carb dismantled/cleaned. Stock jets/adjustments. Leak down test confirms air-tight engine. New points/condenser. Balls-on timing. Pipe is clean. New, lightly-oiled air filter. It has gone through three heat cycles. The bike starts right up and idles great. Smooth transition through all carburetor rev ranges. In short, it runs like a top. Then, out of the blue, I will pull up to a stop and at idle, it simply dies. Always at idle. It will not restart. This happens if I've been riding for three or thirty minutes so I don't think its a condenser overheating issue. The plug color looks a perfect medium tan, but it is ever so slightly wet with fuel (NOT oil-fouled). I thought it was loading up so I tried roll-starting it down a long hill with the petcocks off, ignition on, and throttle wide open with no luck. Then I replace the plug and the whole process repeats itself. I, as always, appreciate any suggestions regarding what stone to tip over in search of the culprit.

[Bullfrog]

Sounds like an ignition fault of some sort. Time for some VOM work, close inspection of connectors and spark plug cap. Mayhaps an inch-by-inch inspection of wires . . . liberal use of a biggify-er lens . . . etc.

[matt glascock]

Good call, Captain. I forgot to mention that I trimmed the (original) high-tension lead and installed a new and more secure spark plug cap. The original cap spun freely on the lead. VOM and biggify-er lens in hand, its off to the land of the nitty gritty for me. I'll report. Thanks Captain!

[taber hodaka]

A wet fouled plug will not spark, If it runs with a new plug and repeats itself, I would think carb. But did I read everything correctly? --------------------- Clarence

[matt glascock]

Hi Clarence. Yes, I went through the carb with a fine tooth comb. All in stock trim currently. Thank you.