Seeking Inside Diameter dimension of 210 Main Jets

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Stillreel

Stillreel

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I'm refusing to give up on the plug fouling problem plaguing my original Amals. I've replace the needle and jets (106 needle, 210 Jets) and it will start and idle but as soon as any throttle is applied, it stalls. This happens at all but extremely rich mixture setting, which is exactly what I'm trying to avoid. It appears that as soon as I apply throttle, the taper chokes off fuel supply at the main jet. But I could be wrong.

I'm wondering if the "Wassel" jets I've been sold are actually cheap Chinese knock-offs with an incorrect ID. Does anyone know what the inside diameter of the 210 jets should be?

If this fails, I'm going to new Amal Premieres.

Thanks
BC
 
Buy real Amal parts. if the manufacturing tolerances aren't right with the Wassel parts you are jut chasing your tail.
 
Try raising the needles, the main jets usually only work above 3/4 throttle when only the tip of the needle is hanging inside the needle jet. In any case trying to use number drills to modify main jets is a futile exercise, you need to use a flow meter and ream them to get the specified flow. This is usually done during manufacture by people who know what the jet number means.
 
I've got a chart that shows #200 at .048" and 220 at .050", so chances are your 210 = .049.
Jaydee
 
Sorry. My bad. I need to check the ID of the needle jet. I'm measuring it at ~ 0.099" which I think is correct. If this is the case, the problem lies elsewhere (?). I'll try lifting the needle one slot (currently middle) see if it helps but new Premieres are looking better al the time.

BC
 
acotrel said:
Try raising the needles, the main jets usually only work above 3/4 throttle when only the tip of the needle is hanging inside the needle jet. In any case trying to use number drills to modify main jets is a futile exercise, you need to use a flow meter and ream them to get the specified flow. This is usually done during manufacture by people who know what the jet number means.
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+1 The mains probably have nothing to do with your issue. Look to needle. Why people are always blaming the main jets is a mystery to me. You could go out and ride all day with no main jets in at all.
 
That's a good observation , that Main Jets aren't much necessary AT ALL. This issue is probably " something else". Float level . Float internal leakage. Float needles ,dirt ,slide/body wear. Slide fracturing. Plug change needed.
 
a .106 needle jet should measure @ .106 and be perfectly round. if as you state it is @ .099 than there is your trouble
Stillreel said:
106 Wassel needle jet. 0.099". Is this correct?
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The parallel part of the NEEDLE should measure 0.0985"
The NEEDLE-JET orifice should measure 0.1060"
Buy a number 36 drill and measure it,The flutes of the drill should measure 0.1065",and shouldn't fit through the jet.
The shank of the drill should measure a little under 0.1060",and will just fit into the jet.
You could buy pin gauges if you want to spend more money.
 
Measuring jet sizes with drill bit flutes is about as accurate as trying to measure cylinder bores with a ruler
for correct measurement buy a plug gauge .106 and it should be a good sliding fit in the jet

by the way I have checked my Wassell .106 needle jets with a .106 gauge and they are spot on
so I think the AMAL propaganda regarding jet calibration is questionable

check your actual fuel level it may be low Commandos suffer with poor manifold depression
which causes issues when moving from pilot circuit to needle jet

that why AMAL used the modified needle and spray tube for the 850 motor
 
Thanks all, for the info. Measuring the ID of the .106 needle jet with drill bits and am able to determine that the orifice is smaller than 0.105". This leads me to believe the 106 "Wassell" needle jet is a piece of &%$#! and I am now looking for genuine Amal Premieres. Walridge sells them, as does Brit Bike in NS. Any other reputable dealers out there, preferably in Canada?
 
Well well , Mike of Walridge sold me 2 kits from Amal of matching jets and needles that went perfect. Not expensive. Wassell too small for I.D. stated size is now noted. There's probably a more accurately calibrated small - I.D. measuring set out there even better than a drillset size stamping. A machinist would know or have, just to be certain as precursor to a complaint process ?
 
Torontonian said:
There's probably a more accurately calibrated small - I.D. measuring set out there even better than a drillset size stamping. A machinist would know or have, just to be certain as precursor to a complaint process ?
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I would never rely on stamped size on a drill bit as being accurate.You need to measure it with a micrometer to be certain.Then it's good enough.You can always turn up a pin to use as a go/no-go gauge.
 
I did use a micrometer. A drill bit shaft with a diameter of 0.1052" will not fit into the needle jet labeled "WASSEL 106". Itsa no good. Itsa no letta da fuel in.

BC
 
It doesn't matter what size the needle jet is, the motor should not miss when under load at 3/4 throttle if the clip is in the centre groove on the needle. It you lower the needle by raising the clip up one notch, you should induce a miss - unless the needle jet is too big. If your jetting is too rich in the midrange (on the needle), your bike will be sluggish however you won't necessarily notice it.
I suggest you might be better off using appropriate Mikuni needles in your Amal carbs, there is a much better range of tapers available. Of course, if you get your bike tuned really well and performing to the max, the outcome might change with the weather.
 
As the main jet only acts at WOT there are those that tune the needle w/o a main jet installed then later size for the WOT power surge.
 
acotrel said:
It doesn't matter what size the needle jet is, the motor should not miss when under load at 3/4 throttle if the clip is in the centre groove on the needle. It you lower the needle by raising the clip up one notch, you should induce a miss - unless the needle jet is too big. If your jetting is too rich in the midrange (on the needle), your bike will be sluggish however you won't necessarily notice it.
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I think the needle-jet size matters VERY much,between idle and 1/3 throttle,and gradually less above that.
The parallel part of the needle is still in the needle jet until 1/3 throttle.A 105 needle jet is about 14% leaner than a 106 needle jet,between idle and 1/3 throttle.

That's enough to be noticable,and right where most street riding is done.
 
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