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[windmill john]

My 350 is fitted with an Amal monobloc. Warm weather, last year, tickled but no choke, can start first kick. I’ve learned over the Winter (actually partly learned) I need to get a real feel for the outside temp and moisture content!
Generally, if temp around zero, full choke and a blip of throttle. 2 to 3 degrees up to 10, I need to really find an exact choke amount!

Rhetorical point... why is it that sometimes I need full choke but also a lot of throttle!? The choke just cuts off air... nothing else... it is part of the slide... you’d think that the amount of right wrist would be the same, but ohhhh no.

[stinkwheel]

Of all the various permutations of carb/engine I've tried, the standard mikcarb is still the best for reliable, fidget-free cold starting and stable idling.

[Wheaters]

Mine started easy enough, the other end of the scale (ful throttle) was appallingly poor.

[stinkwheel]

Mine started easy enough, the other end of the scale (ful throttle) was appallingly poor.

Wouldn't argue with you there, but it's nice to just walk out and prod the kick start and have it fire up.

Really must have another go at putting that VM28 on my 350 again after I went to all the effort of finding a manifold that fits both ends. Got a gasflowed head so I should be able to make it work. Starts and idles fine on it but totally shits the bed as soon as you go over 1/3 throttle (on standard 500 setup). Nasty feeling it will involve emulstion tubes and slide cutaways.

[Paul007]

Hi Guys,
Thank you all again for the info you each give, much appreciated.

Update......
I drained all the fuel including the reserve.
Refilled and flow good.
Stripped the carb...Mikcarb 24
Cleaned out all jets etc, some slightly blocked.
Found carb flange warped ! possibly pulling up before tightening 'o' ring sufficiently ?
Flattened back using emery on flat surface.
Started to refit...
Interesting this bit............
The carb removal was made up from cylinder head with.... gasket, then white nylon type spacer 3-4mm thick, then gasket, then Aluminium 8mm spacer with dropdown tab thingy, then gasket, then white spacer again, then gasket, then 'o' ring on to carb flange !!!!!!!
What a loada spacing why????
Now has one white spacer and Aluminium spacer then carb, with gasket between each and 'o' ring onto white nylon only.
Studs long !
Kicked over 3-4 times decompressed
Pulled choke up
Turned on fuel and ignition
Decompressed as Stinkwheel suggested etc using Ammeter proccess
Kicked and fired on 4th go
Running spluttery so put choke in after 20-30 secs and engine ran smoother but not brill
Checked as suggested for air suck but seems ok.

Questions please.....
Is the little brass screw for mixture, i'm guessing so but how far should it be screwed out in general ?
What's those two Aluminium Spacers people seem to buy to fit to the carb flange and what's the blanked off holes for?

Hopefully play again tomorrow.

Regards,
Paul

I'm getting there..........

[stinkwheel]

There are a load of "extra" spacers on later models because they fitted a pulse air device that feeds air into the exhaust to get it through emissions tests. The valve is operated by the vacuum generated by the carb venturi and it attached to one of those spacers. There will be a stub on the header pipe where the other end of the device attached.

One of the first things most people did was remove it. Usually screwing a self-tapper into the carb spacer to seal the hole and fitting a domed nut to blank off the exhaust stub.

I just have a single fiber spacer in there. The spacing doesn't seem to make much difference to these motors (I think it would need to be hugely long to have any sort of pressure-wave effect). You could even just bolt the carb straight to the head but there can be issues with vibration and a lot of heat being transmitted to the carb which can eventually start boiling/frothing the petrol in the float bowl if you thrash it.

If you are happy the carb is clean and not leaking, next stop would be ignition timing. There is a balance. Too far advanced and it's latchy to start, too far retarded and it starts easily but runs poorly at higher revs.

From memory my mixture screw is roughly 1 1/2 turns out then tweaked but check its current position before fiddling with it so you can put it back again if you make it worse.

Also. make sure you have a good charge in your battery. They will run with rediculously low voltage but get increasingly latchy as it drops.

[Wheaters]

My 350 Bullet Electra has all the spacers but no PAV and from photos of other similar bikes this was how it left the factory. On the thick ally block spacer is (or rather, was) an auxiliary air screw controlling flow via a pipe from the air cleaner housing. It bypasses the carb altogether. I understand this was to allow the idle to be set at high altitude.

The bike has TCI ignition and the timing is controlled by the sealed control module so can’t be adjusted by the owner. There is no clue of the firing point by movement of the ammeter needle because there are no points or distributor, so starting is done by feeling for compression, just like I did on my old BSA which had a 12:1 compression piston fitted.

[PeteF]

The aluminium spacer is for the PAV system. The stub pipe must be blocked if the PAV is removed or better still remove the spacer altogether.

[Wheaters]

Maybe you're thinking of a different setup? The aluminium spacer on my bike has an inlet stub controlled by a needle valve type screw.

As I've said before, there was no PAV on this bike, which is an Indian home market 350 Bullet Electra. Photos of other examples of this particular model show it to be plumbed the same as them.

The clear plastic tube on the inlet stub on the inlet spacer block connector comes directly from the airbox, i.e filtered air. My "Watsonian Squire" workshop manual (issue 3/04, which is the same date as the bike) explains how to set up the idle using what is described as the "auxiliary air valve screw". The text doesn't mention anything about a PAV valve. The diagrams show only the clear plastic tube running directly from the airbox, as per my bike and similarly doesn't show any sort of a valve. The technique to set the idle mixture is to adjust it so that opening the auxiliary air valve screw (which bypasses the carb) doesn't alter the idle speed. Once the auxiliary air "needle" valve is fully closed, it does nothing.

Removal of the spacer tube/block would require shorter fixing studs for the carb, and I see no need to bother because the bike runs very well as it is.

[Wheaters]

Here's the relevant page: