Greg Marsh Amal Carb Syncing Technique

Dellis

Dellis

VIP MEMBER
Joined
Jul 22, 2018
Messages
490
Country flag
Stripped and ultrasonic cleaned the carbs last weekend and used Greg’s method of syncing the carbs, never done it this way before but I have to say this is by far the best method I’ve come across. I usually use vacuum gauges for the final tweaks but these were spot on from the initial adjustment. What’s more is that my Commando is a one or two kick starter apart front the first start after winter which normally involves several kicks to get it fired up but this time it went first kick. Thank you Greg.

Dave
 
Dellis said:
Stripped and ultrasonic cleaned the carbs last weekend and used Greg’s method of syncing the carbs, never done it this way before but I have to say this is by far the best method I’ve come across. I usually use vacuum gauges for the final tweaks but these were spot on from the initial adjustment. What’s more is that my Commando is a one or two kick starter apart front the first start after winter which normally involves several kicks to get it fired up but this time it went first kick. Thank you Greg.

Dave
Click to expand...
I'm 76 and my father who worked at the Norton before WW2 taught me a very similar method and it's never let me down including a CB750.
 
I have always used my fingers on the slides for syncing and adjusting the slides and cables, no need for any other tool or gauges, fingers and a small screw driver for air/idle adjustments, fingers and feel are the most accurate way of doing it, been doing it this way on my Norton for 45+ years and also have never used a timing light on my Norton or Triumphs.

Ashley
 
Yep, I always used Ashman's method UNTIL I, in a fit of currently unimaginable stupidity a couple of years ago, JB Welded a set of long velocity stacks onto my Amal Premiers. Now I can't reach in far enough to touch the slides!

I don't know what I was thinking the day I JB Welded them instead of using, say, Silicone sealer. I wish I could say I'd had a few too many drinks but I had no drinks at all, just a bad case of the dumbass.

But I can certainly give credit for JB Weld's ability to keep things stuck together!
 
I did use lollipop sticks to get the throttle stops synced as I couldn’t feel when the screws were touching the slides other than that I stuck t o Greg’s method.

Dave
 
MexicoMike said:
Yep, I always used Ashman's method UNTIL I, in a fit of currently unimaginable stupidity a couple of years ago, JB Welded a set of long velocity stacks onto my Amal Premiers. Now I can't reach in far enough to touch the slides!

I don't know what I was thinking the day I JB Welded them instead of using, say, Silicone sealer. I wish I could say I'd had a few too many drinks but I had no drinks at all, just a bad case of the dumbass.

But I can certainly give credit for JB Weld's ability to keep things stuck together!
Click to expand...
Use 2 long zipties under the slides - the length means that they are very sensitive to movements of the slides.
Just remember to remove them before starting the engine - don't ask why I know this :)
 
If you are using the drill bit method you need to use the correct bit size to match the cutaway on your slides. Cut away is measured in 1/16th increments, so a #3 is 3/16 bit size. A #3.5 in 7/32. #4 is 1/4.
 
htown16 said:
If you are using the drill bit method you need to use the correct bit size to match the cutaway on your slides. Cut away is measured in 1/16th increments, so a #3 is 3/16 bit size. A #3.5 in 7/32. #4 is 1/4.
Click to expand...
If you’re talking to me, I know nothing about the drill bit method you describe.

I’m synchronising the twistgrip’s lifting of the slides.

I’m using a thin strip that slips loosely in under the slide cutaway. One in each carburettor.

The other end, hanging outside the intake, is longer and heavier, so it dips down when the slide lifts. I adjust the throttle cables so that the two strips dip at the same time.
 
What is wrong with mercury sticks to sync with? I do sync carbs "by hand" when I set up new carbs or cables. But the Mercury stick really fine tunes the sync and it can be done quickly and check the sync when you have done the test rides and plug chops to dial in the carbs without removing any parts other than the equalizer tube. I do it once a season on my bikes just to be sure. There are too many variables to just count on by feel or any other method . The mercury columns show the level of sync throughout the whole slide travel as the slide opens and closes, which is needed to get the perfect sync. I know Jerry Wood still marvels at how well my bikes carburate and how strong they perform when you need to push hard and count on dependable carburation.
 
Using drills, sticks gauge pins or using "feel" on the slides is fine for Initial set up and goes gives mechanical accuracy to each other, But for complete accuracy on the balance of what the engine is actually drawing, there is nothing better than vacuum guages of columns of Mercury.
The task is made even simpler as the balance pipe stubs make the perfect take of point.
If folk are fitting performance components, mlkuni carbs etc. Why wouldn't you balance the carbs accurately?
 
Carl H said:
What is wrong with mercury sticks to sync with? I do sync carbs "by hand" when I set up new carbs or cables. But the Mercury stick really fine tunes the sync and it can be done quickly and check the sync when you have done the test rides and plug chops to dial in the carbs without removing any parts other than the equalizer tube. I do it once a season on my bikes just to be sure. There are too many variables to just count on by feel or any other method . The mercury columns show the level of sync throughout the whole slide travel as the slide opens and closes, which is needed to get the perfect sync. I know Jerry Wood still marvels at how well my bikes carburate and how strong they perform when you need to push hard and count on dependable carburation.
Click to expand...
Right on Carl.
The "toothpick trick" and it's ten variations are a good starting point.
I've had the same CarbStix 46 years, still the last word in syncing.
 
As with most gauges or tools, there are many more things you get to see or realize why the proper tools and techniques show you more info than what the tool's main task is. When you've blue printed as many Amal carbs I have you see that there is small differences in the left and right carbs and lots have major flaws or mistakes. that make good syncing or jetting not even possible.
 

Similar threads

B
A shout-out/thank you to Greg Marsh
Replies
9
Views
1,522
BERT
BERT
Back
Top