amal MK2's

[welding_rod]

hi guys,
        having a spot of bother with some mk2's i fitted to my rocket 3. after much fiddling, the bike runs great, and starts good.....but the transition from 'choke' to normal running, is, well sh*te. cuts out, won't start unless 'choke' put on again, can't ride off to warm motor with choke on.once warm, and choke flicked off, runs REAL good. any suggestions appreciated, as it's spoiling a real sweet running bike.
  cheers    w. rod.

[Searchguru]

Hi Welding!
If I'm teaching you to suck eggs, I apologise
I suggest you take the spark plugs out and get them clinically clean and gapped correctly, or put some new ones in. Then if you can take it for a reasonable spin to get it warm etc (if that's possible). Take out the plugs and see what colour they are. This will give you an indication of the mixture settings that you currently have.
I suspect that your bike is running lean, hence it runs better on choke. The plugs should be a light brownish colour if the mixture is correct. Yours will probably be whiter than that because it is lean, though if the choke has had to be on just to keep it running then they will be black and sooty.
The cause of this could be a leak into the inlet tract so check that the manifold has a good seal to the head and the carbs to the manifold likewise. If you find a leak there then end of problem,probably, if not then remove the carbs and check all the jets are clear. Blow them through and if you can remove the jets them place them in a glass jar, with a lid, and soak them in carb cleaner (toluene). Avoid getting carb cleaner on any rubber components because it is not good for rubber, or your lungs! Any stubborn blockages can be persuaded clear with fuse wire but don't get too brutal or you'll cause more problems.  Remove the floats and check that they float in a pot of fuel or water. Check that the float needles seat properly and reassemble the floats to the carbs. Check the float heights are correct and that the needles are set correctly in the slides. I'm sorry but I don't know the settings for these off the top of my head. Reinstall the carbs to the manifold and head ensuring that you don't create a leak as previously mentioned. Et voila! Problem sorted.
Check this site out for settings/answers to start with, though you may have to use the tried and tested 'suck it and see' method - http://www.hitchcocksmotorcycles.com/amal/mk2_conc_ht.html

Best of luck, Tony.

[L.A.B.]

Various suggestions were offered to you when you asked exactly the same thing on another forum in May this year, what actions have you taken with regard to the advice given then?


It was suggested to you then, that you could try a choke cable kit, as that would probably allow a little more control over the choke plungers than the levers do, or that you disconnect the choke linkage that has apparently been fitted to all three levers and then operate the choke levers independently as you can knock off one choke at a time (this was my own advice given to you at that time) as it would then be possible to start up, and knock off one (preferably the centre carb) choke, and then ride off with either two outer chokes on and one off, or two off and one on, as I find I have to do with my T160 that has three Mikuni VM carbs and practically identical choke plunger and lever arrangement, once I have pulled away I find that the 'on' chokes can be knocked off almost immediately (the R/H one by pressing down on the plunger as its lever isn't easy to reach on the move), the bike is then happy to run with all chokes off even if I need to stop and pull away again within a short distance.      


As I see it (and apparently you do too) that this is a problem of transition between choke 'on' and choke 'off' as the Mk2 Amal lever operated chokes only have the two positions = full on or off, and that this is probably not an actual running mixture problem?  

[welding_rod]

hi LAB, have tried letting choke levers down in graduations, similar to the effect a cable system would have...no different. also tried just using chokes on 2 outer pots, hoping the centre cylinder would 'drag' them along untill the 'normal' running curcuits kicked in.....no joy there either.
          the bike runs realy strongly once off the choke, it's just getting it off the choke thats the problem. ticks over at 750 rpm, accelerates well , and pugs(new champs) seem good colour . so the reason for asking again, was just to see if i'd missed anything, or if there was some one on who has experience of MK2's and could offer a cure, or say sorry dude but they all like that.....in which case it will be the bin, and fit some MK1's back on..... tickle them start bike ride away no fuss.

[fidobsa]

My Hinckley Trident 900 could not be ridden with the choke on. Actually this would have been impossible as the cable was missing so you had to keep the choke pulled in by hand until it was warmed up enough to manage without. In practice this was not a problem as it only needed choke for 20 seconds or so. It would still be lacking a bit of power at that point but would keep going to get you onto the road. How long does yours take before  you can ride off without choke?

[welding_rod]

hi fidobsa,
                it takes an age, you can leave the bike on choke for 5mins plus, engine is warm still a problem when choke switched off. but if i can switch choke off while bike rolling down hill in gear the motor cuts out for a second or so and then fires up again as the momentum keeps it churning round.  once through this stage of p*issing about, you can stop bike and will start and run without choke no problem.
    not sure if these carbs are meant to be able to be ridden with choke on or not, this one can't at moment for sure, as as soon as you open the throttle off the stop, it baulks.

[welding_rod]

 hi guys,            
            quick up date, found some bigger jets for the cold start. bike now starts good and takes throttle. after 20-30 seconds i can RIDE off, and once in second gear, flick choke off and normal running is fine.
 YYYYYYYYYYYYYYYYYEEEEEEEEEEHHHAAAAAAAAAAAAAAAAAAAA
 looks like i'm on the right track. will see how it goes for now, and if any fine tuning alters or improves it even more.
 cheers trev.