[AzCal Retred]

Basic troubleshooting -

Healthy Spark? If not, install new plug, check points. If points are funky, clean up, then check timing.

Carburetion - DO NOT depend on the tap filter. There can be no dust, chunks, crud or water in the float bowl. Use an aftermarket clear filter in 10 - 40 micron range. If it doesn't specify the microns, get one that does.

Carb mount - use 1 1/4" fiber reinforced radiator hose & 2 standard hose clamps. MUCH more sturdy & durable. Cracking in the carb to head connection makes diagnosing trouble harder.

IF there was crud in the float bowl, disassemble & clean. Take out the jets & back blow all passages, WD40 is handy & clean. You should be able to see thru the pilot jet, main jet, needle jet and their emulsion holes. CLEAN is good. Check float level; nominally 24mm - 26mm ( 1"). Make sure the float isn't perforated or saturated & full of gas. Don't forget the Air screw; blow out and set back to where you found it. normally in the 1 1/2 - 3 turns from lightly bottomed range.

With good spark, a clean carb and clean fuel to the carb, it should start & run.

Occasionally an old coil or condenser will quit working when it warms up. If it quits whilst running, immediately check the spark. If unsure, replace the coil & condenser and be done with it. The carb is pretty idiot proof if you keep it's internals clean. Running a screen vs. an air cleaner was SOP for years, but dust/road crud can foul plugs and will accelerate engine wear. Probably not a big deal on the Bullet, just carry extra spark plugs.

[Adrian II]

Excellent advice for the basic 500 Bullet, but there are some detail differences with this particular motorcycle.

1. It's a 350, so the carb bolts on to the head, it has a flange with holes at 2" centers like the Redditch originals rather than a flexible mount.

2. This is (or was originally!) a 350 Electra, so it has fixed electronic ignition on the end of the crankshaft with a TCI somewhere under  the seat, no contact breaker or condenser assembly fitted, there's just a blank space at the back of the timing chest. Still a valid point about the coil, though.

A.

[AzCal Retred]

Good points all, Adrian. In your experience are the Enfield electronic ignitions about as reliable as those of the Japanese bikes of the past 40 years? Most E.I.'s I've seen are pretty bulletproof unless corroded to death. Black Fingernail also made a good point about checking the tank cap vent. Partial vacuum in the tank might account for the problem happening later in the ride, limiting fuel flow to the float bowl. All things for the rider to check.

Regarding bolting the carb to the head - I don't see insulating spacers used on many of these installations. Is there supposed to be, or is this a non-issue on Bullets? The last shot of MikeBE's bike shows what appears to be two spacers(gaskets?) but many of the other bikes pictured as examples do not have anything. In the "olde days" there was concern voiced about the fuel boiling in the float bowl and skewing the mixture ratio unless insulated from the head. Maybe this only applied to cast iron heads like on the very old machines, irons higher specific heat interfering with a hot restart? Or maybe it was all B.S.?

[Adrian II]

The electronic ignitions used on REs seem fundamentally OK, except that there was a serious issue with the TCI on the first Electra-X models causing back-firing when using the Electric start. This wasn't all the time, but a big enough pile of broken sprag clutches was building up under warranty to make RE bring in an extra spark delay unit, then an upgraded TCI box to compensate.

There were also a number of Indian home market 350s fitted with CDI ignition, as far I have been able to tell from people who have experienced them, these seem to be fine.

Mike's 350 has the additional alloy carb spacer with a take-off pipe used for the Pulse Air Valve (PAV), which was an emissions dodge to see these bikes through a previous round of eco-regulations. My old UK-built '57 Bullet had quite a deep alloy spacer between the head and the carb, but that was so that the carb didn't foul the magneto. If there was a tufnol insulating spacer I don't think it was a very thick one. My current Bullets just have have one-piece rubber mounts and gaskets for the carbs and seem OK with just those, but the material provides some insulation against heat from the head that a bolt-on Amal carb (or Indian VM24 Mikarb pre-PAV) would not have, hence the tufnol spacer on so many bikes. I wonder if this was originally a racing thing that found its way onto road bikes.

I take your point about heat being an issue with older cast-iron heads, though I think a lot of vintage carbs were push-fit and clamped to steel inlet stubs screwed into the cylinder head (or block on flat-head engines). A slightly more recent version of this was on the BMW R90S fitted with clamp-on Dell'Orto PHM38s, though these carbs had nylon sleeve between the carb and stub, 1.5mm wall thickness.

I have been looking through the on-line parts books for older UK-built Bullets but can't find either alloy or tufnol spacers, only gaskets. Early versions of the post-war Bullet had Amal carbs with extended bodies to fit around the magdyno, and separate float chambers, which must have been considered adequate to prevent the fuel from overheating.

A.