BritBike Forum logo
BritBike Sponsor BritBike Sponsor BritBike Sponsor
BritBike Sponsor

BritBike Sponsor

BritBike Sponsor
BritBike Sponsor BritBike Sponsor BritBike Sponsor
JWood Auctions JRC Engineering dealers JWood Auctions
Home | Sponsors, Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons, "OLD" BritBike Forum | DVD- Manuals & Parts books | BritBike Stickers & Decals
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
Member Spotlight
Blapper
Blapper
Kent UK
Posts: 4,542
Joined: August 2007
Show All Member Profiles 
Shout Box
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Random Gallery photo
Who's Online Now
22 registered members (Alan_nc), 219 guests, and 434 spiders.
Key: Admin, Global Mod, Mod
Newest Members
Dan1818, Konaflyer, Begbie, Andrew Fallo, Zack Banks
10419 Registered Users
Top Posters(30 Days)
btour 85
Rohan 77
Triless 70
reverb 68
Popular Topics(Views)
713,648 mail-order LSR
Forum Statistics
Forums34
Topics68,327
Posts665,185
Members10,419
Most Online3,995
Feb 13th, 2017
Like BritBike.com on Facebook

Previous Thread
Next Thread
Print Thread
Rate Thread
Page 1 of 2 1 2
Amal float adjustment question #258794
06/12/09 11:21 am
06/12/09 11:21 am
Joined: Apr 2002
Posts: 1,029
Cadillac, MI
JT441 Offline OP

BritBike Forum member
JT441  Offline OP

BritBike Forum member

Joined: Apr 2002
Posts: 1,029
Cadillac, MI
I've read the articles on the AMAL website about adjusting float height and how to determine the float height. I'm not clear on one thing though. When I push down on the tabs on the float, do I measure float height just as the needle seats or when the float begins to press down on the needle instead of lifting it?


JT441
'70 B44
'71 T120
'66 Spitfire
'85 Honda Shadow (the SO's bike)
'90 Honda Pacific Coast
'96 Honda Pacific Coast
Support your #1 BSA Forum and our favorite sponsors

Check out BSA on e-bay: BSA Parts in UK, BSA Motorcycles in UK, BSA Parts in North America, BSA Motorcycles in North America

 
Re: Amal float adjustment question [Re: JT441] #258876
06/12/09 8:29 pm
06/12/09 8:29 pm
Joined: Mar 2005
Posts: 731
Asheville, North Carolina
C
ca7a Offline
BritBike Forum member
ca7a  Offline
BritBike Forum member
C

Joined: Mar 2005
Posts: 731
Asheville, North Carolina
AMAL makes many different styles and models, JT. Which is it?

Re: Amal float adjustment question [Re: ca7a] #258889
06/12/09 9:24 pm
06/12/09 9:24 pm
Joined: Apr 2002
Posts: 1,029
Cadillac, MI
JT441 Offline OP

BritBike Forum member
JT441  Offline OP

BritBike Forum member

Joined: Apr 2002
Posts: 1,029
Cadillac, MI
Oops! AMAL Concentric 930.


JT441
'70 B44
'71 T120
'66 Spitfire
'85 Honda Shadow (the SO's bike)
'90 Honda Pacific Coast
'96 Honda Pacific Coast
Re: Amal float adjustment question [Re: JT441] #258900
06/12/09 9:56 pm
06/12/09 9:56 pm
Joined: May 2004
Posts: 3,862
Sydney Australia
B
BSA_WM20 Offline
BritBike Forum member
BSA_WM20  Offline
BritBike Forum member
B

Joined: May 2004
Posts: 3,862
Sydney Australia
The float height is actually not what you are measuring.
You are measuring the maxium fuel height when the float has stopped the flow.
On 900's it is really easy.
Get another drain plug for the float bowl and insert a bit of thin plastic tube in it.
Run the tube up the side of the carb and turn on the fuel.
Put a little piece of masking tape on the side of the carb so you can mark the fuel level.
If it is a twin carb do both of them.
The float height is not quite as important with single carbs as with twins as it affects the idle and it makes them hard to balance so it is a good idea to get twins matched.
In reality it needs to be low enough so that fuel dose not flow out of the holes in the bottom of the carb body or tickler and high enough so that induction vaccuum can draw it through the idle circuit at kick over speeds.
It is not in any way shape or form a critical measurement unless you are trying to get 2020 performance out of the bike. In 99.999% of cases fiddleing with it will make almost no noticeable difference aswith normal tuneing you are adjusting the air screw to match whatever fuel flow the carb has.
High performance , speed shops and racers do need adjust them, daily riders don't.
It is another thing that has got picked up and become a major issue of worry that to all effects and purposes did not exist


Bike Beesa
Trevor
Re: Amal float adjustment question [Re: BSA_WM20] #258905
06/12/09 10:47 pm
06/12/09 10:47 pm
Joined: Jun 2002
Posts: 10,242
Scotland
S
Stuart Offline
BritBike Forum member
Stuart  Offline
BritBike Forum member
S

Joined: Jun 2002
Posts: 10,242
Scotland
Hi,

Originally Posted by BSA_WM20
The float height is actually not what you are measuring.
You are measuring the maxium fuel height when the float has stopped the flow.

Never seen that definition before. confused Going back years, long before the www, to when I could speak on the 'phone to an actual AMAL technician in an office in Birmingham (GB), the 'float height' was just that.

'JT441': I'm assuming you're trying to set the float height to a particular value - 0.04" or 0.08"? As near as makes no odds, that's 1mm or 2mm respectively. The method I've always used is:-

1. inside the float bowl, opposite the inlet, measure the distance you want down from the gasket face of the bowl and scribe a short line parallel to the gasket face;

2. assemble float, needle, pivot pin, etc. into the bowl;

3. with a thumb over each end of the pivot pin, invert the float bowl; gravity is now mimicking the force fuel would apply to the float and needle when the carb's in normal use;

4. look where the top edge of the float is in relation to the line you scribed in the bowl earlier; adjust float height by moving brass needle seat vertically in bowl;

5. repeat steps 2. to 4. 'til you're happy. wink

Btw, if you haven't done it before, bear in mind it's easy to damage the brass needle seat, after which it'll leak. frown I put the float bowl in hot water (near to boiling if the bowl's old frown ), then use a piece of wooden dowel with the end shaped so it engages in the seat to push on the seat; again, if a bowl's old, I have a small hammer to hand, to tap on the other end of the dowel to get the seat moving. One thing I never do is use any metal tool on the seat itself.

Hth.

Regards,

Re: Amal float adjustment question [Re: Stuart] #258985
06/13/09 2:04 pm
06/13/09 2:04 pm
Joined: Mar 2005
Posts: 731
Asheville, North Carolina
C
ca7a Offline
BritBike Forum member
ca7a  Offline
BritBike Forum member
C

Joined: Mar 2005
Posts: 731
Asheville, North Carolina
Trevor has the better approach, I believe: it's the fuel level, not float height that needs setting.

A simple test is to remove the pilot screw and tilt the bike to that side. At about 15 degrees tilt, fuel should start to trickle out of the screw hole. This works with AMAL types 2, 3 and GP carbs, and with Mikuni VM's. I don't know about the 9 series.

AMAL type 3's have a float chamber cover with a small pip cast on the outside of the cover that tells where the fuel level should be. How one can practically use this info is a mystery to me, so I fabricated a clear cover with a mark on it at this pip location to visually confirm the fuel level.

David

Re: Amal float adjustment question [Re: ca7a] #259034
06/13/09 10:36 pm
06/13/09 10:36 pm
Joined: May 2004
Posts: 3,862
Sydney Australia
B
BSA_WM20 Offline
BritBike Forum member
BSA_WM20  Offline
BritBike Forum member
B

Joined: May 2004
Posts: 3,862
Sydney Australia
Ok I admit that my text was not as accurate as it should have been.
Yes what we get told is to "set the float height" but what the float height is doing is controlling the fuel height in the bowl and that is what is important.
But the rest still stands.
Particularly for concentrics where they are extreamly tollerant of mal adjustments and have a wide range of acceptable parrameters.
It is not worth worrying about on most singles but dose cause problems if a pair of them are not the same.
They can both be high or both low just as long as they are the same.


Bike Beesa
Trevor
Re: Amal float adjustment question [Re: BSA_WM20] #259232
06/15/09 12:26 pm
06/15/09 12:26 pm
Joined: Apr 2002
Posts: 1,029
Cadillac, MI
JT441 Offline OP

BritBike Forum member
JT441  Offline OP

BritBike Forum member

Joined: Apr 2002
Posts: 1,029
Cadillac, MI
Thanks all. We've got them adjusted and the bike starts easily and idles nicely even when cold. The carbs are not original to the bike since it should have GP carbs ('66 Spitfire). We had quite a bit of trouble with it running too rich and progressively kept changing the notch in the needle we had the spring clip in. This problem was compounded by the fact that the we found that one of the spring clips was bad and kept allowing the needle to push up through the center to the spring. We swapped a good clip out of one of the other bikes and that cured that problem. We had to go all the way to the #1 (top) notch in the needle to cure the too rich condition. I don't know how old or how much use the carbs have had but I suspect that the main jet may be worn. They have 190 main jets fitted. I think I'll order new 190 jets, new needles, and based on an intermitent leaking problem, new brass float needles. I'll probably swap out the nylon float needles in all of my bikes while I'm at it since shipping will probably cost me more than the parts any way.


JT441
'70 B44
'71 T120
'66 Spitfire
'85 Honda Shadow (the SO's bike)
'90 Honda Pacific Coast
'96 Honda Pacific Coast
Re: Amal float adjustment question [Re: JT441] #259235
06/15/09 12:43 pm
06/15/09 12:43 pm
Joined: Aug 2001
Posts: 254
Duesseldorf/Germany
Phil in Germany Offline
BritBike Forum member
Phil in Germany  Offline
BritBike Forum member

Joined: Aug 2001
Posts: 254
Duesseldorf/Germany
JT;

the main jets should be okay. It is the needle jets and needles that get worn by vibration. So if you order new parts get the .106 needle jets. To cure richness they are much more important than the mains.
The viton-tipped brass needles are perfect for the concentrics.
FWIW

Last edited by Phil in Germany; 06/15/09 12:58 pm.

Best regards
Phil
Duesseldorf/Germany
'62 A 65 Star (disassembled)
'69 A 65 Lightning
'71 A 65 Firebird
'75 T 160
'84 Yamaha SR 500
Re: Amal float adjustment question [Re: JT441] #259244
06/15/09 1:36 pm
06/15/09 1:36 pm
Joined: Mar 2005
Posts: 10,221
Boston, Massachusetts
J
John Healy Offline
BritBike Forum member
John Healy  Offline
BritBike Forum member
J

Joined: Mar 2005
Posts: 10,221
Boston, Massachusetts
ca7a: These plastic float bowl covers were common "in the day" and sold by the US distributors. Lacking plastic float bowl cover, one can remove the acorn shaped cover from the pilot jet and put a small plastic tube on the its threads. The tube then can be held along side of the float bowl cover an the fuel level in the tube compared to the "pip" in the middle of the cover.

For those who don't eat, sleep, drink... Amals when ca7a is referring to the 3 series he means 375, 376, 389 and 689 Monoblocs.

While it is certainly fuel level we are interested in, it has a direct relationship with position of the float when the float needle is seated. Thus the short hand method of using .060" to .080" stated in Triumph Service bulletins. Because you have to take the body on and off the carburetor several times to reset the float level after using the "sight glass" method of determining fuel level, why not just take the bowl off once and use the time tested method of float height.

Now, I agree with Trevor that the Concentric is especially forgiving as to float height, unlike its cousin the Mikuni, but there are valid reasons for the average rider to have it checked. This is especially true when one is having problems with the carburetor. The fuel level is the foundation for all of the fuel circuits. It effects idle through full throttle.

Over the past 15 to 20 years we have had three different manufacturers of AMAL carburetors. We have also had many varied opinions, quality of production (especially of the floats themselves) and other issues that have influenced why I always recommend checking the float itself, and the float/fuel level, using what ever technique you choose.

An an example of a deviation is the information published in the Norton Tech Digest: it recommends a float level where the top of the float is level with the top of the float bowl. This places the float about 1/16" above the bowl and it can hit the bottom of the carb body and hold the float needle open. It also makes for a very rich overall mixture. Beside being rich, if a thinner float bowl gasket is offered, or the stock gasket compresses with age, it increases the chance the float will foul the body.

While the original drawing of the float bowl and its related parts illustrates the bowl as described in the Norton Tech Digest, in practice the carburetor works better with the float level described in the Triumph Service Bulletins. It could be that Norton owners were trying to overcome the "lean" jetting mandated by the US EPA with out replacing the cut spray tube and lean needle. But setting the float/fuel level that high on a Triumph or BSA just doesn't seem to work all that well.

While the AMAL production was in the hands of Grosvenor Works in London, thousands of floats were produced with the needle tangs not level with the top of the float body. They were taken out of the mould while the plastic was still soft and the tangs drooped. All of these floats made their way into spare parts or production. Many of these floats are still in unsold carburetors and dealers spare parts. When this was discovered a tool was developed to individually check the tangs before they were issued to production or for spares parts, so it is not a problem with current production. This is NOT an "urban legend."

JT441 main jets do not wear, but effectively get smaller with age. The leading edge of any tube that flows a gas or fluid has an effect upon the amount the tube, or jet, will flow. The velocity stack on the air inlet is a good example. With age the brass the jet is made from "blooms" from oxidation. This oxidation seems to be most prevalent on the sharp leading edge of the tube that forms the jet. This totally upsets the flow of fuel through the jet. When these jets are made and checked on a manometer for flow the worker uses a burnishing tool to "worry" that sharp edge to adjust the flow. Imagine when you look at that leading edge, and instead of a nice rounded edge that promotes fuel flow, it looks like a rocky outcrop. Unless you have a manometer and the standard to compare the jets flow you cannot clean the edge to restore the original flow.

Now, the needle jet does wear, a lot. As little as .001" wear in the needle jet will cause the bike to run rich. Especially rich at the point where we use these bikes the most: 1/8 to 1/3 throttle. Because the straight part of the needle (.0985") does not leave the needle jet until approx. 1/3 throttle (depends upon needle clip position) the Delta area of only .0075" created by the needle and needle jet is dramatically effected by very, very small changes in the needle jet size. It isn't until the tapered part of the needle enters the needle jet does the taper begin to have an effect upon carburation. Again, depending upon needle clip position, it can be as high as 1/3 throttle.

You are most likely having problems with the spring clip that located the needle by failing to make sure it centered in the needle jet as you offer the slide assembly to the body. This is a common fault overcome with some patience and practice.


Re: Amal float adjustment question [Re: John Healy] #259250
06/15/09 1:52 pm
06/15/09 1:52 pm
Joined: Jul 2001
Posts: 12,962
Central Virginia
Lannis Offline

Life member
Lannis  Offline

Life member

Joined: Jul 2001
Posts: 12,962
Central Virginia
Originally Posted by John Healy
The fuel level is the foundation for all of the fuel circuits. It effects idle through full throttle.



John -

WHY does it affect all that? As long as there is fuel available to flow into the main jet, and as long as it isn't spilling into the manifold from being too high, how does it make a difference where the actual surface of the fuel is?

Surely the amount of fuel that flows isn't affected by a mil or two of "head pressure", not in that bouncing, splashing, tilting, vibrating environment inside that bowl?

Lannis


I stopped believing for a little while this morning. Journey is really going to be upset.
Re: Amal float adjustment question [Re: Lannis] #259269
06/15/09 3:09 pm
06/15/09 3:09 pm
Joined: Mar 2005
Posts: 10,221
Boston, Massachusetts
J
John Healy Offline
BritBike Forum member
John Healy  Offline
BritBike Forum member
J

Joined: Mar 2005
Posts: 10,221
Boston, Massachusetts
For the same reason there are variations in the location of the main jet itself. For two strokes the main jet is located higher in the body and on the four stroke version it is lowered. It is for the same reason opening up the cross drilled holes on the four stroke needle jet as little as .002" from the standard .035" makes a dramatic effect upon the amount of fuel delivered. For the same reason that the location (height in body) of the orifice in the needle jet is different in the two stroke than in a four stroke. It is the same as small changes in the primary air bleed makes changes in the amount of fuel delivered to the inlet port. For the same reason changes in barometric pressure will change the overall jetting of the carburetor. For the same reason changes in elevation will change the overall jetting of the carburetor. For the same reason small differences in piston ring sealing will make changes the overall jetting of the carburetor. For the same reason different cam duration will change the overall jetting of the carburetor. For the same reason an overly advance ignition timing will change the overall jetting of the carburetor.

All these effect the "work" being done moving fuel up, out of the float bowl into the intake track. Any change to the distance the fuel needs to be moved or changes in air bleeds which change manifold/venturi vacuum, or atmospheric changes is going to change the amount of fuel delivered.

All this and a lot more effect the amount of fuel delivered by a carburetor. Knowing the fuel level removes one more variable and establishes a base point to which you can return. If you could see the dramatic effect of just rubbing a burnishing tool over the leading edge of the main jet does to the amount of fuel it delivers you will begin to understand the importance of having a known fuel height that has proven to work.

Just look at the needle jet. We can agree that three needle jets cover most 4 stroke requirements: .105", .106" and .107". Anyone who has worked with these carburetors know that if a bike was originally fitted with a .106" needle jet, that a .105" would be too lean and .107" would be too rich. We are talking .001" difference from running too lean, with the potential of seizure, to running too rich and the motor 8 stroking. If as little as .001" difference in the needle jet will make such a dramatic difference you can begin to see that an 1/8 difference in fuel level in the bowl is going to effect how the carburetor works. It isn't uncommon to find fuel levels/float heights that are as much as a 1/4" than those specified by Triumph in their Service Bulletins.

Yes, the beauty of the AMAL Concentric, other physical issues aside, is how tolerant it is to lack of understanding about how it works and what changes do. But this is no excuse to be a cowboy...


Re: Amal float adjustment question [Re: John Healy] #259299
06/15/09 5:37 pm
06/15/09 5:37 pm
Joined: Apr 2002
Posts: 1,029
Cadillac, MI
JT441 Offline OP

BritBike Forum member
JT441  Offline OP

BritBike Forum member

Joined: Apr 2002
Posts: 1,029
Cadillac, MI
I need to restudy my AMAL literature. I think that what I called the main jet is actually the needle jet. I'll print this thread off and add it to my reference binder. Thanks for all of the information guys. The BSA owners manual and shop manual sure don't offer much information on Amals.


JT441
'70 B44
'71 T120
'66 Spitfire
'85 Honda Shadow (the SO's bike)
'90 Honda Pacific Coast
'96 Honda Pacific Coast
Re: Amal float adjustment question [Re: John Healy] #259317
06/15/09 8:08 pm
06/15/09 8:08 pm
Joined: Jul 2001
Posts: 12,962
Central Virginia
Lannis Offline

Life member
Lannis  Offline

Life member

Joined: Jul 2001
Posts: 12,962
Central Virginia
Originally Posted by John Healy


All these effect the "work" being done moving fuel up, out of the float bowl into the intake track. Any change to the distance the fuel needs to be moved or changes in air bleeds which change manifold/venturi vacuum, or atmospheric changes is going to change the amount of fuel delivered.



By the way, I'm not trying to have a technical duel or p!ssing contest here, I'm woefully underequipped for either of those. I'm just trying to state the hard parts in my understanding of this fuel-into-the-cylinder process.

It's just hard for me to imagine that the venturi vacuum in the carb throat knows much about what's down in the float bowl.

The float bowl could be tiny or could hold 3 gallons and that shouldn't matter, for the same reason that the hydrostatic pressure on a dam at a given depth is not affected by the size of the lake behind it.

The ONLY thing that the vacuum sees is:

1) The effective area of the jet (as and if modified by the needle).
2) The distance of the surface of the fuel in the jet below the venturi.

The ability of the liquid fuel to jump off the surface within the jet is going to be determined by the surface tension, the natural vapor pressure of the fuel, and the vacuum above it.

I wish I could draw a picture, but suppose the fuel level surface in the jet is .350" below the venturi (whatever reference point we use, as long as it's always the same). No matter whether it's .350" or something else, the vapor pressure of the liquid fuel and surface tension are going to be the same for a given temperature.

So if the engine is pulling some level of vacuum "V" at the venturi reference point, what's the vacuum/pressure profile over the .350" from there down to the fuel surface? Isn't it going to be fairly constant? Is there going to be a big difference if it's .300" or .400" down the jet?

What other forces are operating to make such a change in how much fuel gets sucked up the jet?

Lannis


I stopped believing for a little while this morning. Journey is really going to be upset.
Re: Amal float adjustment question [Re: Lannis] #259342
06/15/09 10:15 pm
06/15/09 10:15 pm
Joined: Mar 2005
Posts: 10,221
Boston, Massachusetts
J
John Healy Offline
BritBike Forum member
John Healy  Offline
BritBike Forum member
J

Joined: Mar 2005
Posts: 10,221
Boston, Massachusetts
"The distance of the surface of the fuel in the jet below the venturi."

and the weight of the fuel in the main jet passage. The longer the passage, as with the 4 stroke condition, the stronger signal, or difference between venturi vacuum and atmospheric pressure, required to lift the fuel.

All subtle stuff, but well thought out.


Re: Amal float adjustment question [Re: John Healy] #259374
06/16/09 1:49 am
06/16/09 1:49 am
Joined: Jul 2001
Posts: 12,962
Central Virginia
Lannis Offline

Life member
Lannis  Offline

Life member

Joined: Jul 2001
Posts: 12,962
Central Virginia
I guess I hadn't thought about the fact that liquid fuel is actually flowing up the jet, and not droplets being pulled off the fuel surface inside the jet. The liquid fuel doesn't turn into droplets until it hits the airflow in the venturi.

Makes sense.

Lannis


I stopped believing for a little while this morning. Journey is really going to be upset.
Re: Amal float adjustment question [Re: Phil in Germany] #259405
06/16/09 9:41 am
06/16/09 9:41 am
Joined: Jun 2002
Posts: 10,242
Scotland
S
Stuart Offline
BritBike Forum member
Stuart  Offline
BritBike Forum member
S

Joined: Jun 2002
Posts: 10,242
Scotland
Hi,

Originally Posted by Phil in Germany
if you order new parts get the .106 needle jets. To cure richness they are much more important than the mains.

Although I appreciate it might not transfer directly from triples, several owners have detailed on the Triples On Line Forum that they've solved richness low down with modern fuels with .105 needle jets.

Hth.

Regards,

Re: Amal float adjustment question [Re: Stuart] #259420
06/16/09 12:14 pm
06/16/09 12:14 pm
Joined: Apr 2002
Posts: 1,029
Cadillac, MI
JT441 Offline OP

BritBike Forum member
JT441  Offline OP

BritBike Forum member

Joined: Apr 2002
Posts: 1,029
Cadillac, MI
Okay. I've got the float height sorted and you've straightened me out on the difference between a main jet and a needle jet. After a 20 mile ride yesterday where the bike ran great and the plugs looked pretty good, should I consider replacing the needle jets since I had to set the needles in the top notch? The bike pulled great, started first or second kick hot or cold and idled better than any of my other British bikes. If I get new needle jets, should I get .106s as Phil suggests? Do I need a special tool to remove/replace the needle jets?


JT441
'70 B44
'71 T120
'66 Spitfire
'85 Honda Shadow (the SO's bike)
'90 Honda Pacific Coast
'96 Honda Pacific Coast
Re: Amal float adjustment question [Re: JT441] #259437
06/16/09 2:02 pm
06/16/09 2:02 pm
Joined: Feb 2004
Posts: 1,956
Flint,Mich
norbsa48503 Offline
BritBike Forum member
norbsa48503  Offline
BritBike Forum member

Joined: Feb 2004
Posts: 1,956
Flint,Mich
I had found a source for NJ that were reamed badly and under size. I was able to get them at cost, so with a .1055 reamer I fixed them. Now all my bikes that call for .106's get this fix.
The new mix of summer fuels with low volatility act rich and this fix seems to brighten up the response all through the mid range. Remember that all the stock settings were on the rich side to start. Your mileage may vary of course. Once your bike is all seated in tuning using MPG has been a safe approach for me not ignoring plug color though. PM me if you would like to try this but get it all broke in first.


norbsa
1960 TR6
1963 Super Rocket
1965 650 Star
1966 441
1968 Thunderbolt
1969 Twinkle 250
1972 Fastback
1974 Roadster
1970 S.S
Way too many BSA's not named
http://decentcycles.com
Re: Amal float adjustment question [Re: norbsa48503] #259450
06/16/09 3:22 pm
06/16/09 3:22 pm
Joined: Mar 2005
Posts: 10,221
Boston, Massachusetts
J
John Healy Offline
BritBike Forum member
John Healy  Offline
BritBike Forum member
J

Joined: Mar 2005
Posts: 10,221
Boston, Massachusetts
Stuart:
There is another way of doing the same thing, but instead of going one full jet size, you can open one, or both, of the cross drilled bleed holes in the needle jet. This makes for more subtle changes. It is sort of like hitting it with a pillow instead of a hammer. It also tends to keep the change to the period where the straight part of the needle is still in the jet.

This should only be done in .001" to .002" increments at a time!!!!!! Opening the cross jet holes from the standard .035" up to .050" renders the jet useless... the carb. will no longer function properly. We have had some luck with .039."
HTH



Re: Amal float adjustment question [Re: John Healy] #259481
06/16/09 5:33 pm
06/16/09 5:33 pm
Joined: Aug 2001
Posts: 1,839
British Columbia
hh Offline
BritBike Forum member
hh  Offline
BritBike Forum member

Joined: Aug 2001
Posts: 1,839
British Columbia
My '70 TR25W, which shares the exact bore and stroke of the triple, simply would not tune no matter what with a new .106 needle jet and needle after I had the carb sleeved. When I put in a .105, it was like magic and has never been so responsive with no flat spots or hesitation whatsoever.


"Beer is proof that God loves us and wants us to be happy" - Benjamin Franklin
Re: Amal float adjustment question [Re: hh] #259540
06/17/09 12:50 am
06/17/09 12:50 am
Joined: Mar 2005
Posts: 10,221
Boston, Massachusetts
J
John Healy Offline
BritBike Forum member
John Healy  Offline
BritBike Forum member
J

Joined: Mar 2005
Posts: 10,221
Boston, Massachusetts
hh:
Most people who sleeve Concentrics believe that AMAL left too much clearance on the slide. They believe that AMAL was either sloppy or not good enough machinsts to do it "right" (their choice of words). It is far from the case.

The original jetting (in your case .106") is built around .0035 to .004" slide clearance. By closing up the slide clearance it produces a stronger signal on the jet. It also increase the chance the slide will stick ten fold. It comes as no surprise that you had to fit .105" needle jets as it is a common complaint from people who have there AMAL sleeved.

There is a very good reason why AMAL provides the .0035" to .004" clearance it does! That is if you care about the person riding the motorcycle. With the .001" to .0015" clearance I often find with sleeved AMAL's, it takes even less over tightening of the flange bolts before the slide sticks. Often barely snugging them up will cause the slide to stick. This is no less a problem with sleeved Monobloc's.


Re: Amal float adjustment question [Re: John Healy] #259680
06/17/09 4:57 pm
06/17/09 4:57 pm
Joined: Jun 2002
Posts: 10,242
Scotland
S
Stuart Offline
BritBike Forum member
Stuart  Offline
BritBike Forum member
S

Joined: Jun 2002
Posts: 10,242
Scotland
Hi John,

Originally Posted by John Healy
There is another way of doing the same thing,

Thanks, I'll bear it in mind for myself and pass it on.

Regards,

Last edited by Stuart; 06/17/09 4:57 pm.
Re: Amal float adjustment question [Re: Stuart] #259717
06/17/09 9:50 pm
06/17/09 9:50 pm
Joined: Feb 2005
Posts: 6,478
NYC and York PA
wadeschields Offline

BritBike Forum member
wadeschields  Offline

BritBike Forum member

Joined: Feb 2005
Posts: 6,478
NYC and York PA
John - What was the tool for cleaning out the pilot jet? I should have taken notes at the TCH rally.
Thanks


http://wadeschields.tumblr.com/

Jack of all trades . Master of fun! wink

Beer is not the Answer.... Its the Question..... The answer is YES

[Linked Image]
Re: Amal float adjustment question [Re: wadeschields] #259724
06/17/09 10:53 pm
06/17/09 10:53 pm
Joined: May 2004
Posts: 3,862
Sydney Australia
B
BSA_WM20 Offline
BritBike Forum member
BSA_WM20  Offline
BritBike Forum member
B

Joined: May 2004
Posts: 3,862
Sydney Australia
A No 78 drill mounted is a piece of thin plastic tube or a couple of pieces of heat shrink rotated with the forefinger & thumb with little to no pushing pressure


Bike Beesa
Trevor
Page 1 of 2 1 2

Moderated by  Allan Gill, Jon W. Whitley 


Home | Sponsors | Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons | "OLD" BritBike Forum | DVD- Manuals & Parts books | BritBike Stickers & Decals
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
Powered by UBB.threads™ PHP Forum Software 7.6.2