I have a TR-3B which I've owned since the early 70's. It was a daily driver until a few years ago. Now I'm retired I'm trying to get it running again. I've rebuilt the carbs, new sprockets and chain, new plugs, points and condenser, new fuel filters and flushed the gas tank.
The engine will start and idle ok once it has warmed up. Currently the carbs are set at 15 and 18 flats open with SM needles. The timing is at 5 deg. btdc. I just replaced the vacuum advance on the distributor and tested the vacuum line to insure it's not leaking. There is fuel pressure and flow at the carbs. I have 10W30 oil in the dashpots. Compression is 175 psi in all cylinders. Years ago (but not many miles ago) I replaced the carb butterflies and shafts with new bushings, so I don't think shaft wear is an issue.
When I try to drive, the engine will misfire with slight acceleration. With more acceleration, it misfires badly. Hard acceleration causes a backfire through the carbs.
I'm running out of things to check. I have not checked the head for carbon buildup or the cam for wear.
Can anyone suggest what could be causing my misfire and backfires?
The engine will start and idle ok once it has warmed up. Currently the carbs are set at 15 and 18 flats open with SM needles. The timing is at 5 deg. btdc. I just replaced the vacuum advance on the distributor and tested the vacuum line to insure it's not leaking. There is fuel pressure and flow at the carbs. I have 10W30 oil in the dashpots. Compression is 175 psi in all cylinders. Years ago (but not many miles ago) I replaced the carb butterflies and shafts with new bushings, so I don't think shaft wear is an issue.
When I try to drive, the engine will misfire with slight acceleration. With more acceleration, it misfires badly. Hard acceleration causes a backfire through the carbs.
I'm running out of things to check. I have not checked the head for carbon buildup or the cam for wear.
Can anyone suggest what could be causing my misfire and backfires?