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[windmill john]

What do you mean it won’t tickover on the side stand.... it will if you set it to 2000 rpm

I played with my monobloc initially, upped the needle jet if I recall, it was running very lean. It’s not perfect, but I don’t want to end up chasing my tail to get the perfect feeling in the whole Rev range.

I may do at some point....

[Rattlebattle]

On the first point I'd say go for the carb conversion. On the second point the Concentric that our host supplies with the kit is the standard one with the monkey metal slide and the non-removable idle jet. That said mine has worked fine for the last three years and required only the tickover to be adjusted - it came jetted for the free-flowing silencer. IMHO Concentrics are unfairly maligned, based on experiences of owners trying to balance knackered twin carbs. On a single they are easy to tune. I always turn off the petrol tap as I near my house and run the float bowl dry. Perhaps not strictly necessary with E5 fuel, but good practice for when we're stuck with E10. EFI does have an advantage in that it is less susceptible to poor fuel because it runs under pressure. it is also much better at changing altitudes, though really that's not an issue here. Given a choice I would have preferred a Monobloc, which is really more in keeping with the era these bikes are trying to emulate, plus they can be adjusted without a screwdriver (possibly a minus too if some 'erbert decides to fiddle with it). I dare say the Mikuni is a better carb but to my mind it doesn't look right and I've had zero issues with my Concentric. FWIW I wouldn't bother with the choke lever; it only needs a good tickle to start from cold, part of the ritual. Another upside of converting to a carb is that you can get rid of the Godawful cold start device (on pre-Euro IV bikes, dunno about those). This improves the clutch action no end because it isn't sharing limited space passing through the grommet in the headlight.

[Adrian]

If you DO end up with the non-premier Concentric and the zinc alloy slide, you can still get something better for it. Surrey Cycles are Amal specialists and they sell heavy brass slides for the Mk1 and Mk2 Concentric carbs, this is a much better wearing combination of metals, I'm surprised our hosts haven't latched onto this.

A.

[windmill john]

I’m new to monoblocs. Very simple I know; the carb that is!

I find I have to use full choke, but at the same time, give it throttle to start; what a contradiction!
So you’d think it’s running too weak, but when warm, I’ve used a Colortune To set the mixture So now spot on.
I’ve also tickled to start, but find I just hope for best!

[Presto]

I realise it's obvious to the point of seeming stupid - but this sort of thing ought not to happen with a new carb. And equally obviously happens in only a fraction of cases.

Amal Mk1 Concentrics - standard or Premier - are fitted to 1000's of bikes and run perfectly. Some may want to disagree - but it's an indisputable fact - and has been so for over 40 years!

If this failing carb was purchased new then it ought to have been returned to the seller in the first few days who ought to have identified the fault and/or replaced it.

It doesn't make sense to criticise (as some in this thread have done) the design/manufacture of a perfectly serviceable make of carburettor because this one has an evident fault. I guess in a sense the fact that the engine is running well with a Concentric proves the point!

[Presto]

Apologies - that post belongs to another thread!!!!!

[Jerseyplym]

The interesting thing about the current version of the carb conversion kit is that it retains the ECU and uses it for the ignition timing - so it's not really doing away with the electronics.
The old one had a different rotor which allowed the use of (I think!) an Electra X electronic ignition "black box" instead and did not need the ECU.

[Daiwiskers]

One thing people seem to have missed myself included

I know the bike has been fitted with free flowing exhaust and inlet

Is there a cat in the header pipe?

If so that'll have to be dealt with before you fit the carb

Also a fuel tap will need fitting and fuel pump removing

I'm not sure what comes with the different kits but it will be worth checking

One last thing I would not run a air cooled bike with a cat no way no how

Take care all Dai

[Adrian]

The interesting thing about the current version of the carb conversion kit is that it retains the ECU and uses it for the ignition timing - so it's not really doing away with the electronics.
The old one had a different rotor which allowed the use of (I think!) an Electra X electronic ignition "black box" instead and did not need the ECU.

They obviously found a way to relegate the existing ECU to a purely TCI function, saves having to swap black boxes and alternator rotors out, and makes it easier to revert to fuel injection if a new owner desires.

A.

[Rattlebattle]

It's doing away with the potentially troublesome aspect of the electronics; the ignition side seldom causes problems as only two sensors remain connected (crank position and engine temperature), though the latter doesn't actually do anything any more as far as I can tell. When I fitted my carb conversion three years ago I asked Hitchcock's how come they now sell a cheaper kit that doesn't require an ECU replacement. They told me that in their testing of the system keeping the existing ECU they had found it worked just as well as the earlier version. You get everything needed in the kit, including a new plate drilled and tapped to take the supplied fuel tap. It's an easy conversion to do, maybe half a day. You can either leave the MIL light connection as it is, in which case it will glow all the time, so in effect it shows that the ignition is on, or you can do what I ultimately did and disconnect the feed to the light, in which case it obviously never comes on. I did the latter because it annoyed me being permanently lit and it's no better at tracing ignition faults than just removing the spark plug and testing it. I have reused the original large o-ring on the tank plate several times and it has never leaked. I also find that you don't really have to drain all the fuel from the tank, though obviously it's better to do the job when the fuel level is low. I'd also advise keeping the EFI bits - you never know when the powers that be might outlaw mods that effectively mean that the bike is no longer Euro 3 (or, possibly more risky Euro IV compliant).