Hitchcocks Forum

Just to sense check something.

After putting distributor back on (350 iron barrel) following Pete Snidel's book, I seem to have insufficient adjustment on my backplate as still pinging quite a bit and I am at the end of the slot, need to go further CW i think?

Guess i was not careful enough when putting it all back together

To save me draining the oil and taking the timing cover off again can I just move the A&R unit/points Cam round a bit by taking it off with it's extractor, rotating and tapping it back on to it's taper?

I can’t see why not….a set of points is only a simple switch.

No problem moving points cam
Our hosts have a how to for setting timing

Cheers Dai

Yes. You can.

Our hosts sell a special tool for dismounting it but I suspect you could also just use a bolt. If you do buy the tool, it's worth getting the dished washer to lock it at fully advanced at the same time. It's a lot easier to set it fully advanced than static because the piston doesn't keep rocking over TDC.

Thanks and yes all on tech note, washer/extractor ordered and will set full advance at 8.5mm BTDC. Good point as rocking back and forward looking for 0.8mm BTDC is dam near impossible!

Well, have to admit that made quite a difference, I have set the timing many times before retarded at 0.8mm and with varying levels of positive results but nothing compared to 8.5 advanced, bike is very different, faster, more power and even sounds better. Just been out for a blast and once warmed up straight to an indicated 70+ (aka 60+) and getting up hills where it previously struggled! The couple of quid on the extractor and washer was money well spent!

I can see why they went for crankshaft mounted ignitions with the electronic timing in a fixed position on later models. They USUALLY machined the key slot in the crankshaft in the correct position.

Also bear in mind that there can be quite a bit of slop the the overall meshing of the train of timing pinions, the crank pinion, the two cam gears, the two idler gears and finally the "distributor" or magneto pinion. A little bit of excess clearance between each set of gear teeth soon adds up, that can allow the ignition timing to wobble around by up to 10°. You can compensate for this when timing with the timing cover off by gently rotating the final gear anti-clockwise so as to take up all the slop before fastening it in the fully-advanced position.

Never mind, you seem to have hit the sweet spot, enjoy the results.

A.

I've seen videos of "Bullet Wallahs" on the streets of India adjusting the timing on the fly. They get it close so the bike will start and idle and leave the backplate screws done up so they're not quite nipped. Then, with the engine idling, they tap the back plate one way and the other with the handle of a screwdriver until they get the fastest, cleanest idle and nip the screws down. In much the same way as you'd set a pilot air screw.

There is a sweet spot where they start first kick without backfiring but rev up crisply.

Makes perfect sense as every engine is a bit different i guess.

Just walked in from a quick ride to the shops, with a slight downhill and gentle wind behind me had an indicated 85, first time the speedo has ever been there!

Not bad as over 8000 miles stock 350 still on original Micarb with standard main jet but with open Briteuro silencer, Iridium plug (with non resister cap) and have fitted a no 2 slide cutaway and bigger pilot jet.

Could be the point where they run great shorty before exploding!

Only if you give it too much exuberant riding! The original 350 design was a good one in its day, so if you ride the bike with a degree of mechanical sympathy, you ought to get a decent mileage out of it.

A.