New Amal 932 carb adjusting

maylar

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Compared to my other Brit bikes the Commando's seem to "hunt" a bit at idle. I'm wondering if minor flexing of the timing chain is messing with the advance. The timing chains definitely have tighter and looser spots when adjusting tension. These bikes all have Pazon Surefire ei's. Maybe the timing chain flutter would be less noticable with points with centrifugal advance.
Timing chain wear can be seen as a flutter when strobing, but it's too rapid to have any effect on idle speed. Hunting is usually carb wear especially if it changes with temperature.
 
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Amal 932 premiere tuning… finally successful

NOTE: BIG UPS TO HTOWN16!!! Without his help I'd still be kicking with no result. Thanks M

Turns out - by using the choke I was flooding it, badly, which in turn fouled the plugs (quickly) thusly made starting / running / tuning a huge challenge.

Per HTown16’s help – this is what I did just yesterday.

I removed the fouled NGK iridium resistor plugs and installed a new set of Denso IW22 / 5307 resistor plugs (my personal choice), with the gap set at 28. I connected plug wires, tested spark... all good, both sides. Installed plugs, connected plug wires... done.

Air filter off… I rechecked slide synchro which remained equal. I reset the slide height using a 7/32 drill bit (my choice, in-between 3/16 and ¼) and checked Sharpie marks on Throttle Stop screw – all good. replaced air filter.

Rechecked Pilot Air screw, confirmed set at 1 & ¼ out. This setting was recommended when I changed out the pilot jets from #17’s to #19’s.

CHOKE OFF - Fuel taps on… hold down tickler till fuel emerges… key on… kick once… twice… a third time and nothing. Concerned about lack of air = flooding / fouling, I turned Throttle Stop screw one full turn in (lifting slides). Key back on… kick once and a sputter… I now opened the throttle 25% (approx.) kicked again and VAROOM. Not only did it start immediately, but it sat at 1300 rpms at idle, even after blipping the throttle a few times. My opinion... my slide height setting success was pure dumb luck.

I let the engine warm up then slowly adjusted the Throttle Stop screws out to drop the rpms… about a 1/8th turn out each side… the rpms now sit at 1100, steady.

Went for a ride, about 30 minutes, which included neighbor streets, a highway, and avenues… Every stop the idle returned to 1100, every time. Acceleration was smooth with no hiccups, wheezes or snorts – smooth. It’s a miracle. I consider my starting / idling issue solved… at least for now.

I’m learning all our bikes are the same, but very different. Lots of trial and error, but when it we get it right… it’s awesome. In my case, my 850 doesn’t like to be choked, but then… who does?

Thank you Htown16… I’ll be checking in soon when I begin work on my clutch. I noticed some slipping while riding #Itneverends
 
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If you want to get a four-stroke motor going well, perhaps you should start by learning to tune a two-stroke motor ?
 
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If you want to get a four-stroke motor going well, perhaps you should start by learning to tune a two-stroke motor ?

Maybe 2 stroke bike vs OPE 2 stroke...Apples and oranges.
In the last 8 years I have been given 80+ chain saws-weed wackers and blowers. fixed 95% and most of the problems were E-10 poisoning causing damage to the carbs.
This causes extreme carburation problems which can occasionally burn the piston and cylinder.
The main difference is the F/A progression of the main circuit. The 2 stroke when LOADED and running at a 80% rpm but at peak torque.
If UNLOADED and then reving close to 100% it will revert from normal 2 stroke ratio and go into rich 4 stroke mode.
The difference to 4 stroke engine is a quite different fuel air progression. It would be explained similar to running a bike flat out and the carb dispensing gas as if the choke was slowly being engaged.
If you then tune the OPE 2 stroke carb for flat out (on a 4 stroke engine) , a 2 stroke OPE carb design will be still be leaner at less than flat out and burn up the engine. Try it some time and be prepared to buy a new piston and cylinder...
I'd be curious to know if marine 2 stroke works more like OPE or 2 stroke bike A/F progression.
 
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If you want to get a four-stroke motor going well, perhaps you should start by learning to tune a two-stroke motor ?
I've learnt to tune 2 stroke carbs by junking the original carbs in the bin and fitting more modern up to date carbs. Don't quite see the connection between the two, it's like chalk and cheese.
You yourself fit Mikuni needles into Amals carbs, so. . . . . .
 
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Thanks Eric, Dialing in these new 932's is work. By saying "drowning in air" I should have said it was more like pressing the kill switch when I twisted the throttle. Note... it happens as my rpms indicate I'm transitioning off the main jet (as it switches to the idle jet)... like I should wait another sec before blipping it.

Since then I've had some good success... starts on one or two kicks... warms up at 800 to 1000 rpm... throttles nicely (I never have trouble from 1/4 twist to full open)... drops to a steady 1100 rpm's when I stop. But inevitably, either later that day, or a day or two after I start having trouble.

One thought I had was I was causing it by blipping the throttle as my carb transitioned from main jet to idle jet thus disrupting the mechanics of the transition. Or the bike is leaning out as it gets hot (San Diego has been unseasonably warm the last 6 weeks)

Right now, my slide height setting seems Ok for an 1100 or so RPM idle... My air screws are at maybe one full out, or about a 1/16th turn in from a full turn. Is this just too rich to work from?

Heading out to the garage to try again.
 
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