JS Motorsports Carbs

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hi Jim,
thanks for that, after cutting my 5mm off the filter boot, i used the flat side of my bench grinder to make sure I had a nice finished edge, not some raggy cut with scissors!!
I am in Singapore at present at work and not back to the bike until first week of Jan, so will give you that answer on the SHCS size then . I have some vernier calipers to check.
I did notice a balance tube in the pic you posted showing the filter clearance.???
I hope me posting pics hasn't puy prospective buyers off, they worh fantastic. me just being fussy is all.
Regards Mike
 
SHCS means socket head cap screw, or in laymans terms , Allen headed screw or bolt, as you use Allen keys to fasten them
Regards mike
 
Brooking 850 said:
SHCS means socket head cap screw
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Oh good cuz I couldn't find a 32mm SHCS Carb anywhere on Google.

This is a good thread with a lot of positive feed back on these carbs. It almost lost me with the few negative comments but then Jim chimed in and now I am back to wanting to buy them.
The filter mod to the stock unit is the way to go I think. It's now winter here and I have a lot of fun ahead of me working on the bike.
Carbs, ISO and trans work. That should keep me busy for awhile.
 
Negative comments related to Amal carbs are very very common, but seemingly this doesnt stop people buying them, even though the new "Premier" Amal's seem to be suggesting the earlier ones werent fit for purpose!
 
The "premire" amals are offered with all the improvments made in the 40 or 50 years since the original ones came out. Floats and seats for modern fuels and a changable idle circuit. Things that were not an issue with the original design.
 
They still offer both, but from what I have read they are phasing out the original ones and replacing them with the premire.
 
bwolfie said:
They still offer both, but from what I have read they are phasing out the original ones and replacing them with the premire.
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Are the new carbs the same price as the old ones, and does anyone who has purchased an old type carb recently get sent the new parts FOC so old carb can be used with modern fuels?
 
You really need to get to the doctor and get your memory loss diagnosed and treated. This has been discussed at length 2 months ago.

Email from Amal

Greetings from The AMAL Carburetter Company,

We hope this email finds you well and you find the following of interest...

Introducing the AMAL Mk1 Premier Concentric Carburetter

We are pleased to announce the introduction of the new AMAL Mk1 Premier Concentric Carburetter.

The 900 Series AMAL Mk1 carburetter for four stroke applications has been re-designed to improve performance and wear.

The new carburetter incorporates changes in materials which reduce the rate of slide and body wear and a precision engineered idle circuit which improves the pick performance from idle and reduces fuel consumption. The precision manufactured forged alloy hard anodised throttle slide has a low friction surface for smoother operation and greater wear resistance. The material of the carburetter body has a “passivated” finish which resists corrosion. The ethanol resistant, puncture proof Stayup float and Viton tipped alloy needle valve improve control of the fuel flow.

A new easily removable pilot jet provides precise metering of the idle circuit. The jet, which is located in the opposite position to the Pilot Air Screw, is manufactured to tight tolerances allowing it to be replaced with minimum disruption to the adjustment of the carburetter. Initially the size of the jet replicates the 622/107 pilot bush. Other sizes will be available shortly. Removal of the jet allows access to the rest of the idle circuit for servicing.





The new jet cannot be fitted to earlier versions of the Mk1 Concentric.

The new carburetter is available in 28mm, 30mm and 32mm bore sizes and with right or left hand pilot adjustment.

The carburetters can be ordered by adding “Prem” to an existing specification number. E.g. 930/300Prem.

We will be launching the Premier Carburetters at the 18th Carole Nash Classic Motorcycle Mechanics Show at the Stafford County Show Ground on the 15th - 16th of October...
 
If they are still selling the old type carbs which cant be used with modern fuels, one wonders where in the world anyone who has these carbs would be able to easily obtain fuel without ethanol added?
 
The old style carbs work just fine when properly fettled, even with modern fuels (just don't use the late style cheap plastic floats & needles).
 
If the old type floats and needles work ok with modern fuels, then why on earth are customers being asked to pay extra for updated parts to replace ones which work perfectly well?
 
I've read that a few guys have relocated the ignition switch when converting to the JS Carbs.... is this required?
 
Hi Johnnymac, the answer is no to your ignition switch relocation, although if you remove the original aircleaner backing plate, then yes you will have to relocate the switch.
How I fitted my JS carbs after setting cable lengths, ie syncronizing the carbs, is to bolt on the manifolds to the head using the heat resistant gaskets that were on my original manifolds, completely assemble new JS Keihins with rubber boots and airfliters all clamped on and cables connected and carb tops screwed back on, then slide the rubber boot (with loose clamp in place on either the manifold or the rubber boot) over the manifold coming from an angle slightly under the ignition switch. If you think it is to tight a fit, remove the switch from its mount, (dont need to disconnect any wiring) and replace it after the carb c/w airfilter is in place. Tighten the hose clamp/jubilee clamp, job done.The right hand carb is done the same way but you don't have any interference from the switch or mount. Takes a couple of minutes each carb set up. Easy eh????
way easier than Amals which have bolts and are difficult to get out.
Regards Mike
 
Johnnymac said:
I've read that a few guys have relocated the ignition switch when converting to the JS Carbs.... is this required?
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Not me - '73 750

Mounting is a snap. Manifolds first, carbs second, filters third.

I have only one small tiny niggling concern with the JSM kit. It is that the cups of the cable adjusting barrels that are integrated into the supplied cables are a bit shallow - as compared to the usual depth I've seen before with British cables. That is, the male ferrules of the cables do not sit as deep into the female cups of the aduster ends. They are OK if in the middle of a straight run but if the ferrule/barrel junction is in the midst of a curve, then I had concerns that with cable wear or jostling of the wiring harness or the on & off of the tank, that they could slip out, causing intermittent slide imbalance.

I used some zip tie "cut offs," the useless ends, as splints. I zip tied the splints to bridge the adjuster barrel and on each side to hold the cable ends tight into the adjusting barrels' cups. You could do the same thing with simple electric tape. With the zip ties, as opposed to tape, I can still adjust the adjuster barrels while knowing the cable ends can't jump out.
 
I emailed all of my carb customers and got several replies. Some bikes have plenty of room between the backing plate and aircleaners, some just touch and some are too tight. This may be an isolastic sagging condition. So in some cases the backing plate needs to be removed and a new ignition switch mounting bracket fabricated. Or I just may shorten the aircleaners and supply narrow clamps for another 3/16" clearance. I will start on that project today.

In answer to John Laing about his cable adjuster post above.
I no longer supply cables with adjusters. The adjusters are now part of the carb tops. I still use the first style on my own bike and they are fine.
 
jseng1 said:
The adjusters are now part of the carb tops.
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I think that is what he was referring to in that those adjusters cups aren't deep like the Amal kind and are more shallow so support isn't there if the cables are not in line going straight into the adjuster cups.
Is that what you meant Mike?
 
Xbackslider,
if you are still having an issue with the cable ends being to shallow in the cups, before loading your flatslides onto the end of the cables, slide some thick walled 'heat shrink' over the cable, (all the joints if necessary)assemble your flatslides onto the cable, mount back into the adjuster, push the heat shrink over the whole joint, and heat with the heat gun. might also look neater than your splint method.
Regards mike
 
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