Hard starting when warm-ish

When cold (winter), my 1974 Commando 850 starts on 2 kicks with full choke. If I have been riding, and I shut it off for a few minutes (to fill up or to talk to someone), it restarts beautiflly with about 1/2 a kick. However, there is this in-between time period if the bike has been sitting for more than about 30 minutes where it takes a ton of throttle and a ton of kicks (at least 10!!!) to get it restarted. And even then, once started, I have to keep it on a faster idle manually with the throttle or it will die. No amount of choke in warm weather makes starting any easier so i just leave the choke alone in those conditions. It's been a very frusterating and sweaty proposition to say the least.

I'm running a single Mikuni and a Pazon ignition, and other than this problem, it runs beautifully.

Any ideas? Thank you.

Martin

I think the problem is it is simply starved for fuel, enough time has gone by for any fuel in the chamber'manifold to disapate

When I turn the throttle a good half way and hold it open while a good healthy kick, she fires up strongly under your conditions

My 850 is set up the same and does exactly the same thing,it's the transition between cold and at the correct running temp, mine was better with a 2.5 slide,but was changed for a3# to fix a rough cruising problem.

This worked for me on an Amal Mk1.5, which has a similar "all or nothing" cold start plunger to the Mikuni's I think.

When the full enrichment of the choke is not required, apply full choke, but slightly open the throttle just a little bit, to reduce the effect of the choke.

This situation is a bit tricky for me.

My normal routine is to tickle the carbs when the engine is cold, and no tickle when warm/hot. My rule of thumb is: If the jugs are warm to the touch, no tickle; if they're cool, tickle.

Now, I usually get it right, where its rarely more than two kicks to start warm, usually just one.

I also turn off the fuel about a block or two from stopping to minimize flooding.

What you may find is there is too much fuel that's why the bike starts on a wide throttle. Low air velocity through a wide open carb = less gas. To get shot of the eccess gas leave the ignition off and give the motor a couple of kick overs with the throttle fully open then start as normal.

Cash

From your description I'd also wonder if it was flooding when shut down. Then you might not have a spark that is hot enough to fire that fuel charged mixture. What you say you do to get it to run seems to be the same moves one would make to clear a flood.
Another possibilty is what was mentioned about heat soak getting the fuel out, but then I don't see why it would act flooded.. To find out keep a plug wrench andy and next time it does it pull a plug and see if it is fuel soaked or dry.

Go back to Amal concentrics as God intended.

I love ticklers.

grandpaul said:

Go back to Amal concentrics as God intended.

I love ticklers.

Click to expand...

I'm with GP on this one and even if I'm a bit ambivalent, Commandos love ticklers and that's what's important

Thanks to all my Commando mates for the helpful and funny advice. I'm riding tomorrow so I'll check out the remedies.

Cheers.