Starting problems

Hi all.
Recently bought a '74 Interstate that has been standing unused for 10 years or so and I'm having problems getting the old girl running. With a squirt of start spray into each carb I can kick her into life but it then dies after 2-3 seconds, no matter whether I rev it or just let it idle. During the short time it's running it sounds like it's running very cleanly, with no spluttering or misfiring, etc. This led me to believe that it's a fuelling problem rather than an ignition problem so I cleaned the carbs out and changed to fresh fuel. Still no better.
Next I cleaned out the pilot gas jets according to Bushman's carb-tuning secrets and resealed where I had drilled out the carb bodies. Still no better.
The carbs don't appear to be too worn, I was told to check for play in the slides at about half-throttle and there is very little. The fuel taps flow as they should, the float bowls fill and if I press on the ticklers fuels leaks out as it should. The carbs and jetting are all standard. The choke slides are removed and holes sealed. Battery is fully charged.
So, can anyone here point me in the right direction as to what more I could check? Desperate to get out on the road with her and get my first taste of riding a British classic.
Cheers!
Paul

One 74 that sat at my place for some years after a decade somewhere did same taeaser fire up then die with direct carb spray and could not get any change by pilot screw turning till float level corrected till pilot screww effective to sustain idle and beyond. Commando can have combo of things causing same thing so might check for wire loose and bounced looser on firing - key, kill and points and coils and ever loving Earth conductors.

Carbs passages are likely still plugged. This time, verify flow through every passage using spray solvent. There is a chamber closed with an expanding plug, it may, or may not be able to be cleaned with the plug in place.

What I find clogs carbs is the whitish zinc oxide leached out of the pot metal so only mild acid like acetic acid or phos acid in rust and scale bathroom sprays or physical removal works. Organic solvents only take the color out of the oxide crusts leaving cleaner looking crust. Most miserable to track down is broken copper under intact insulation that connects until vibed slowly or only connects at high vibes. Air leak at intake or exhaust side might do this short rev up die thing too.

Thanks for the replies. After spending the whole evening out in the garage i've finally got her running! Seems it was the float heights that was the problem. I moved the float needle seat slightly so as to effectively change the float height. Unfortunately I've gone a bit too far with the adjustment and now the carbs are leaking fuel so I'll have to pull them apart again tomorrow and try and find the sweet spot. Still, really glad to have located the problem at last.

The float height really shouldn't be that critical. I would look at the idle passage again and, as suggested, verify with a spray that it's actually clear. I suspect that by changing the float height to where it's too high you've accidentally created a burnable mixture to make it run but haven't really solved the problem.

What price sanity?

Old Amals are almost impossible to clean completely, and, if you are one of the lucky ones you'll be looking at the same issue in less than 2 years.

The relatively new Amal Premier model carbs seem to have addressed all the issues found in previous iterations, but, conservatively, I'd say that the "jury is still out".

A Mikuni conversion is a good option; you'll lose some top-end power, but you also lose any issues associated with synchronization. The Mikuni also offers considerably more jetting options and tends to have more local-ish vendors for parts/seals. The Mikuni will also suck up idle jets, but they are easy to replace and much less expensive than the Amal counterparts.

Probably needs to be in a new thread but here are some points to consider. Have premiums on my 74 Commando and on my 73 Trident.
First, use great care in removing and replacing the new removable idle jet. When I replaced mine after inspection and cleaning despite
great care turned it off! ...as in severed the head from the jet. I left it in as it was and glued the head in. Seem fine. But unless you
are or have a good machinist you are looking at a new body. Not funny or cheap.
The premiums on the Commando are happy, idle fine run fine. Perhaps I could raise the needle a notch or try a different cutaway as they
are a trifle lean at slow speeds. Removing and replacing Commando carbs is a pain so maybe over the winter.
As for the Trident, I cannot get a good idle unless Im 3/4 turn out or less. Same on all carbs. So the floats are too low I suspect. Nearly, but
not quite, as annoying as removing and replacing the carbs on a Commando.

Suggest you keep them drained over the winter or over longer inactivity periods during the season. Avoid ethanol. Fortunately we now have
now ethanol 91 octane in our area. 75 cents more a gallon than regular ethanol. But the dollar difference may be worth it.

I see Burlen is offering alloy carb bodies in the smaller sizes. Id have gone for them if they had them on offer when I purchased. Well I
would have for the Trident, none yet for the Commando available. But maybe worth thinking about.

Sanity is priceless while motorcyles are pricey. Carefuly tap float needle seat back up till bowls stop over flow then diddle pilot our to 1 turn to start then diddle so idle ok. Try the anodized slide and one size less cut out and may decent runner to spend more on other things. My Amal had worn bore and slide to not idle below 2000 and had flutes in them but working a treat 7-8000 mile till something else stopped show. If carbs still trouble can buy new w/o the slides and combine the money put in.

Well, after removing, adjusting & replacing the carbs more times than I care to mention, I've still not got things working properly so I've bitten the bullet and ordered a pair of Premiers. Did consider the single Mikuni but prefer the original look the Premiers give. Hoping to get them on by next weekend so I'll post the outcome here.

So,... You've already committed to buy the premier carbs, but don't discount trying something like a new set of plugs too. I've torn my hair out trying to figure out why my bike wouldn't run. It was a intermittently bad plug.

It happened after a complete rebuild, so I feared that maybe my cam timing was wrong. I messed with the carbs endlessly. I could get the bike to go Pop, pop, pop and it would die.... It was a god damn spark plug that was bad. After I figured it out and put a pair of new plugs in, the bike started. I fine tuned the ignition timing with a strobe light, adjusted the carbs, and I was on my way to a decently running bike.

Because the bike went pop, pop, pop when I kicked it, I assumed the ignition was good and my plugs were firing. I thought that my issue was the carbs and I messed with them for hours on end over the course of a few days... Don't overlook the ignition. Test the coils, check all the wires for good connections, and try new plugs... good luck

Not much you can do if a 'good' spark plug turns on you and goes 'bad': no chance of rehabilitation once they turn.
However, AMAL carbys are often 'misunderstood' and seem to be playing up just to get your attention. I'm of the opinion that they can be rehabilitated with nurturing care although I am also aware some people have no time for their antics and simple replace them with 'nice' new ones. To those people I say "Send to me all your naughty, your wayward, your erratic, your 'bad' carbys and I will gratefully receive them and implement a corrective regime upon them to eventually return them to motorcycling society as functional and capable 'reformed' carbys". Note/warning: some may be used for experiments (scientific of course, like vivisection without the vivi-) but it will be for the greater good of british bikes especially Norton Commandos, trust me . PM for shipping address .
Ta.

Many Amals are bad out the box d/t casting cooling distortions and bores wear about as much as slides and fastener threads get fouled or worn and outsides get dull, life is short eat desert first and ride more. Hang the old ones up like bull fight trophy. I glance at that area to see if a familiar pair rounded shapes. Sure wish some way to preserve the bright finish and ease way to grime out nooks.

Glad to say that I've got the new Premiers fitted now and she seems to be running very nicely. I'm impressed by the Premiers, they seem to be very decent quality so I think I made the right choice. Only been for a sneaky ride around the block so far as the bike isn't yet road-legal (though it's going for it's first roadworthiness test since 1999 tomorrow, so fingers crossed) and I've been busy stripping & rebuilding the front brake caliper & master cylinder. So hoping to get out for a proper ride very soon, but will be taking a few tools with me, just in case

Hi Delbert, you say you ordered your amals on the 25 july, well I ordered mine on the 16 july and still haven't got them. They say their waiting for parts to come in , and i thought they were a stock standard item at burlens, plus I`m in the UK.
:cry:

Got mine from RGM in the UK. Ordered on the Friday & they turned up here in Sweden the following Wednesday lunchtime. Not bad.

I`LL GIVE THEM A RING.
Just received email from amal saying they are still waiting for the 301 body and this will be 6 to 8 weeks!!
Bloody useless.
I don't think they are made in China or India as they would have them made and shipped by the weekend.
Thanks
chris r