How to determine worn amals? Opinions on wassell?

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StephenP

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Oct 23, 2021
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I determined the issue with my 850 is not ignition, it has a strong blue spark, I sprayed out the pilot jets and i can once again get it to start first or second kick. However it wont idle. It’s either super high and erratic, or idles lower then dies. Pilot screws are 1.5 turns out and i am trying to set speed with the stop screws. No combination works. I am sure i am still fighting a partially clogged pilot, but since i have owned this bike i have always chased idle to a degree. I could get it where i want it, but never trust it for more than about 30 seconds to not go dead. But. Who needs it to idle longer than that? And if the temp outside changed more than 10 degrees i would have to tweak pilot screws..


I kinda suspect they are just worn. How do you make that determination?

I do not wanr to go to a mikuni, and i can’t justify $700 on premiers. Has anyone had any luck with the wassell evos?


*EDIT*

I went inside and took a long shower and calmed down, popped the breather off pulled idle and pilot screws out installed the thumb screws. And felt for when the idle screw engaged the slide went in probably two turns, set pilot screws at 1.25 turns out and walked the idle down from there and it’s about where i like it. Still finicky still don’t trust it at all red light with my hand totally away from the throttle, but then again i never have.
 
Last edited:
StephenP said:
I determined the issue with my 850 is not ignition, it has a strong blue spark, I sprayed out the pilot jets and i can once again get it to start first or second kick. However it wont idle. It’s either super high and erratic, or idles lower then dies. Pilot screws are 1.5 turns out and i am trying to set speed with the stop screws. No combination works. I am sure i am still fighting a partially clogged pilot, but since i have owned this bike i have always chased idle to a degree. I could get it where i want it, but never trust it for more than about 30 seconds to not go dead. But. Who needs it to idle longer than that? And if the temp outside changed more than 10 degrees i would have to tweak pilot screws..


I kinda suspect they are just worn. How do you make that determination?

I do not wanr to go to a mikuni, and i can’t justify $700 on premiers. Has anyone had any luck with the wassell evos?
Click to expand...
So it's worn out old carbs . How many miles are on them approx. ?
You can easily determine if the slide in body fit is worn out . Remove the air filter and the 2 rubbers . Using a thumb and forefinger , reach in and grab a slide bottom . Wiggle it . Any sloppiness and it's new carb (s) time . You can also save money by having them resleeved in bronze , Bruce Chessell here in Ont. Canada did mine , very pleased . Seeing as you have pilot jet issues too .. New ?
These eventually started to wear on me , so I bought a pair of New Wassel's , 32 mm , anodized slides , direct copies of new Amal units with removeable pilot jets . After 3 years they run great .
 
I fix the pilot jet problem first, they can be tricky to unclog need the wire trick then spray, I ran my original Amals even when the slides were worn, just effected the idling more than anything, by the time I replaced them with new Amals my slides were so worn you could just about turn them in the slide area only thing stopping them was the keyway lol, also needles and jet wear out as well.
 
Last edited:
Torontonian said:
So it's worn out old carbs . How many miles are on them approx. ?
You can easily determine if the slide in body fit is worn out . Remove the air filter and the 2 rubbers . Using a thumb and forefinger , reach in and grab a slide bottom . Wiggle it . Any sloppiness and it's new carb (s) time . You can also save money by having them resleeved in bronze , Bruce Chessell here in Ont. Canada did mine , very pleased . Seeing as you have pilot jet issues too .. New ?
These eventually started to wear on me , so I bought a pair of New Wassel's , 32 mm , anodized slides , direct copies of new Amal units with removeable pilot jets . After 3 years they run great .
Click to expand...
Speedo has 9k on it. It hasn’t worked since i have owned it. So i have no idea
 
StephenP said:
I determined the issue with my 850 is not ignition, it has a strong blue spark, I sprayed out the pilot jets and i can once again get it to start first or second kick. However it wont idle. It’s either super high and erratic, or idles lower then dies. Pilot screws are 1.5 turns out and i am trying to set speed with the stop screws. No combination works. I am sure i am still fighting a partially clogged pilot, but since i have owned this bike i have always chased idle to a degree. I could get it where i want it, but never trust it for more than about 30 seconds to not go dead. But. Who needs it to idle longer than that? And if the temp outside changed more than 10 degrees i would have to tweak pilot screws..


I kinda suspect they are just worn. How do you make that determination?

I do not wanr to go to a mikuni, and i can’t justify $700 on premiers. Has anyone had any luck with the wassell evos?


*EDIT*

I went inside and took a long shower and calmed down, popped the breather off pulled idle and pilot screws out installed the thumb screws. And felt for when the idle screw engaged the slide went in probably two turns, set pilot screws at 1.25 turns out and walked the idle down from there and it’s about where i like it. Still finicky still don’t trust it at all red light with my hand totally away from the throttle, but then again i never have.
Click to expand...
You will have to rod the pilot jets out
Take a look a Bushman's carb tuning secrets website
 
So let's say 10 K. or more miles . Typically they wear out around that , or a bit more . Violent shakings to the carbs will do that . Time to $pend . It's winter now in N.A. , so best time to do it .
 
Put a set of Wassels on the last Commando I did. Had Amal Premiers on the others. The Wassels worked fine but finish is not quite as nice as the Amals. IMHO spending money on original carbs is like pouring it down a rat hole. The new ones have removable pilot jets, anodized slides and stay up ethonal resistant floats. Time you do a resleeve and buy all new parts you will be getting pretty close to the cost of new carbs.
 
If I had an original Commando, I would probably struggle on with Amal carbs. But a more sensible thing to do, might be to investigate the engine management system on the large capacity Royal Enfield twins. It might even be cheaper.
It can be amazing what can work well. My mate had a green frame Ducati 750SS. He got an ignition system from a VT750 Honda, and made the crank trigger for it. It took a few attempts but he got it to advance-up very nicely. The bike was much nicer to ride - less harsh.
 
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Post #2. Pete,
Your Quote:
"You can also save money by having them resleeved in bronze , Bruce Chessell here in Ont. Canada did mine".

I think the OP should look elsewhere.

Bruce Chessell does not take on new work as far a I know through conversations with him at rallies gone by. He is retired. He will look at Amals that he re-sleeved, but as far as any new re-sleeves IMHO, its not going to happen.
But I have had Bruce do many sets for me and they are just great. Great workmanship. 👍

To the OP:
StephenP,
Re-sleeving is an option but you need to replace jets/ needles etc. etc., so the price will add up to almost the same as a new unit and you still have zinc bodies.

The New Amal MK1 Premier's are 100% better than the original 1968 designed zinc bodied and zinc slide type that lasted at best 5000 miles before they wore out. They were made to a price, As cheap as possible. Forced on from the British M/C industry during that era.

With that said:

The New Premiers have,
New slide design, stay up floats, new pilot jet design, Lighter bodies because they are alloy as opposed to zinc. ( 3/4 lbs per carb less weight) They are stronger and less susceptible to warping or galling.
I have a pair on my 850 Interstate and love them. I got mine from BCS but Walridge carries them now. Seeing you are in the US try and check out Greg Marsh. He can set you up for your Commando by your bikes year.

Vintage British Motorcycles Home - GME

The home of Greg Marsh Enterprises Vintage British Motorcycle Parts and Service
www.gregmarsh.com
He knows his stuff.
See what he can do for you.
Cheers,
Tom
 
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CanukNortonNut said:
Post #2. Pete,
Your Quote:
"You can also save money by having them resleeved in bronze , Bruce Chessell here in Ont. Canada did mine".

I think the OP should look elsewhere.

Bruce Chessell does not take on new work as far a I know through conversations with him at rallies gone by. He is retired. He will look at Amals that he re-sleeved, but as far as any new re-sleeves IMHO, its not going to happen.
But I have had Bruce do many sets for me and they are just great. Great workmanship. 👍

To the OP:
StephenP,
Re-sleeving is an option but you need to replace jets and needles so the price will add up to almost the same as a new unit.

The New Amal MK1 Premier's are 100% better than the original 1968 designed zinc bodied and zinc slide type that lasted at best 5000 miles before they wore out. They were made to a price, As cheap as possible. Forced on from the British M/C industry during that era.

With that said:

The New Priemers have,
New slide design, stay up floats, new pilot jet design, Lighter bodies because they are alloy as opposed to zinc. ( 3/4 lbs per carb less weight) They are stronger and less suseptable to warping or gaulling.
I have a pair on my 850 Interstate and love them. I got mine from BCS but Walridge carries them now. Seeing you are in the US try and check out Greg Marsh. He can set you up for your Commando by your bikes year.

Vintage British Motorcycles Home - GME

The home of Greg Marsh Enterprises Vintage British Motorcycle Parts and Service
www.gregmarsh.com
He knows his stuff.
See what he can do for you.
Cheers,
Tom
Click to expand...
Plus one on new Premiers - love mine .
 
I agree that the carbs are probably scrap. However, part of your problem could be that the carbs are not synchronized. If the slides are even a bit off from each other the idle will do that sudden spiking or shutting off completely. You can spend a lot of time trying to get it running right. Before I install the carbs I always match the slides on the engine side using a .040 wire gauge to get them as perfect as possible. This helps immensely on the start up. And I have a vacuum gauge for further synchronizing. However, rattly slides will throw a monkey wrench into this process.
 
Before we all get carried away and suggest that the OP fit a set of FCR Mikunis, I would remind you that he is on a tight budget, and it seems that in reply to his original question, a set of Wassel carbs is probably a Good Idea.
 
Whilst it's true that Amal Concentrics are way beyond their best at 10,000 miles, that doesn't mean they won't hold a reliable idle. I went down this path twenty odd years ago on my 850. Even after fitting new Concentrics the thing would still not hold a reliable idle. I tried a single MK2 & later an SU, also with no luck. Then one day some kind person on this forum mentioned that fitting a Trispark had cured the same problem on his Commando. I replaced the Boyer with a Trispark & have since then had a perfect idle.
Whilst the carbs may be causing the problem, I would be interested to know what ignition are you running on the bike?
 
StephenP said:
I determined the issue with my 850 is not ignition, it has a strong blue spark, I sprayed out the pilot jets and i can once again get it to start first or second kick. However it wont idle. It’s either super high and erratic, or idles lower then dies. Pilot screws are 1.5 turns out and i am trying to set speed with the stop screws. No combination works. I am sure i am still fighting a partially clogged pilot, but since i have owned this bike i have always chased idle to a degree. I could get it where i want it, but never trust it for more than about 30 seconds to not go dead. But. Who needs it to idle longer than that? And if the temp outside changed more than 10 degrees i would have to tweak pilot screws..


I kinda suspect they are just worn. How do you make that determination?

I do not wanr to go to a mikuni, and i can’t justify $700 on premiers. Has anyone had any luck with the wassell evos?


*EDIT*

I went inside and took a long shower and calmed down, popped the breather off pulled idle and pilot screws out installed the thumb screws. And felt for when the idle screw engaged the slide went in probably two turns, set pilot screws at 1.25 turns out and walked the idle down from there and it’s about where i like it. Still finicky still don’t trust it at all red light with my hand totally away from the throttle, but then again i never have.
Click to expand...
Have Amal Premiers on my MK3 and they are a doddle to set-up and never had any trouble over 5k miles. I also have a recently acquired 1967 BSA A65 that had original concentric carbs. It would idle fine at around 1k but once hot it would keep creeping up until it reached nearly 2k. Took them apart and cleaned everything including using an ultrasonic tank but still the same. Finally realised slides were slightly sticking when hot and not returning properly. Bit the bullet and purchased new Amal Premiers and now it runs and ticks over perfectly at 1k. Just glad they didn’t stick at high speed🫣
 
Not suggesting it's not carbs, but other factors also mess with a stable, reliable idle. e.g. you might have a good spark, but have you checked your timing with a timing strobe gun? You don't mention which ignition system you have. If it still has original points the auto-advance could be wandering all over the place. Worn and/or loose timing chain....

BTW, I have a single Amal mk2 (34) and a Boyer mk4. Idles nicely, once warm. May be a fluke. No plans to mess with it!
 
I have put a set of the Wassell's on a bike and they work just fine. Not finished as nice as the Amal's, but good enough for the price.
 
Eurojamb has a reasonable price on Wassel carburetors in the USA. If somebody else already mentioned it, I stand accused of repetition.
 
Before blaming the carbs, take a good look at the cross over balance hose on the intake maniflld spigots. A leak or poor fit there will mess up any idle stabilty. Also, try spraying some wd40 etc around carb to mani, mani to head joints while idling....any repeatable idle change indicates an air leak.
 
The amal slides wear and let in more air,.... AND,... at the same time the needle wears on the needle jet and lets in more fuel....... 😏

Most people give up and claim that their carbs are "shot" when the reality might be in many cases, that they don't know how amals work well enough to adjust them properly... In defense of that idea, the numerous potential problems are many with a carb that is a series of complex overlapping circuits. For most people, they only need to make one adjustment to fix their carburetion problem,..... They buy new carburetors...

Some years ago I began using a specific adjustment technique on amals with great success. A friend said exactly the same thing that you are saying about not trusting that the bike will not to cough and die when accelerating from idle speeds. After I finished adjusting his carbs, he said he had been trying to get a non-stumbling acceleration for a long time but couldn't get it. He was surprised that a simple adjustment technique fixed it...

I've got 20,000 miles on my sleeved amals. One year they were starting to feel sticky and the use of some dykem dye proved that they had worn unevenly causing one slide to stick. I sanded out the high spot that was making them stick and they are still working ok...
 
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