Amal Carb

Like many of the Coventry makes, Triumph had their roots in the bicycle industry, beginning motorcycle production in 1902.

Amal Carb

Postby NotTriumphtwin » Mon Jan 25, 2010 12:54 am

My 1970 TR6R has a single Amal 930 carb, as far as I know this is the correct carb for my 650cc motor. The jet sizes are 105 and 210, does this sound anywhere near right or near a good base to work from? As far as I know the motor is stock with the exception of open larger diameter pipes. The needle was set on the top position allowing it to sit as low as possible, I switched it to the middle position and it seemed to improve throttle response a little bit although I didn't go out for a ride just yet. Does my open exhaust hurt my bikes optimal performance and should I try to find some baffles? My pipes are also a little larger diameter, does this hinder performance? My bike seems to take off ok but is no power house when cruising. I don't really want to put another carb on there, even if there is a better one, I just want to make what I've got work as good as it can. Any input is welcome. Since the air choke on my carb is no more, I've heard if I were to fill in the empty space where the slide was that this would help for smoother throttle response, anything to this?

I can't wait for the snow to be gone! :18
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Re: Amal Carb

Postby 850norton » Mon Jan 25, 2010 1:31 am

Give these guys a try:

www.amalcarb.co.uk

info@amalcarb.co.uk if you want to email them

HTH
You sick little monkey!!!!!

http://www.thrashemmotorcycles.blogspot.com

'68 BSA B25 Sarfire, '70 BSA B44 Victor Special
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Re: Amal Carb

Postby Graham B » Mon Jan 25, 2010 2:43 pm

My info says 30mm ie 930 carb is correct size, with 3 1/2 cutaway slide, 230 main jet, 0.106 needle jet (the type with air bleed holes), needle with two scribed identifier rings

But none of these are set in stone and others may know better.

No need to fill the hole for the choke slide in the throttle slide but seal the choke cable entry hole in the carb top with a rivet or screw so extra air doesn't get in there (where it's not supposed to)

What is the outside diameter of your open pipes?

Any chance of a photo so I can see how long the pipes are?

My own feeling is that open pipes will be anti-social and hinder the performance unless you spend some time fiddling with the jetting.

It SHOULD be a powerhouse when cruising with 70-80mph absolutely no strain at all. If it's not, it may be the jetting, those pipes or something else ...

If you intend using it at those speeds, you should get the jetting right and strobe time the ignition (having first made sure the strobe timing marks are correct)

Best of luck :123
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Re: Amal Carb

Postby NotTriumphtwin » Mon Jan 25, 2010 5:30 pm

Thanks guys, I found a great article in the downloads section of the link you posted 850norton, that will come in very handy.

I'm gonna have to pull the carb off again though, I didn't know anything about the cutaway on the slide. I'll have to check that to see what it is. My main is 210, needle jet is 0.105 (the type with air bleed holes) and I believe my needle has two rings or small grooves at the very top but need to verify. I need to measure my pipes to tell you exactly but it looks to me like stock pipes get smaller right after the clamp at the head and mine don't, they stay the same diameter throughout. Here is a pic



Image



The hole for the air slide cable is plugged on top of carb. The loud pipes were cool for about two or maybe three days, now they are not. I want to hear the bike but it's a bit ridiculous. I want to be able to get up early in the morning to go to work and not piss off the neighbors. I know she'll do at least 90mph from a friend riding with me because I have no speedo or tach. I won't be operating at these speeds very often at all but I just want to know my bike has what it needs to operate right through the full range that it can. Thanks again.
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Re: Amal Carb

Postby Bill » Mon Jan 25, 2010 8:13 pm

on my 6T (same motor) i've got a 240 with the needle set in the middle slot. Works a treat. u k fl ag

Also a fellow chop/bobber rider..
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Cool. :211 :150
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Re: Amal Carb

Postby NotTriumphtwin » Tue Jan 26, 2010 2:59 am

Very nice, I like that back tire,16 inch? Wish I had got a more vintage looking back tire. You have the main style of rear frame I see most often, I hardly ever see them like mine. How do you like your high bars? I like the way they look on a lot of bikes but have never road anything with them. I like the way mine look but after a while it's a little back stiffening. You say you have a 240 main, my 210 seems to be the low end of the spectrum from most info. Have you got twin carbs or one, looks like two but can't tell.
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Re: Amal Carb

Postby Allanfox » Tue Jan 26, 2010 9:04 am

I guess the T120C (TT) ran open pipes form stock so you should be able to set up a twin to run well with open pipes. How about fitting a set of these and they are easy to muffle by inserting a baffle in the end. Would also be 'proper' triumph pipes!

Point being if you compare the stock T120 carb setting with the T120 C (TT) setting you should see what tweaks were made to accomodate the open pipes and give you a starting point for the single carb? Maybe?
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Re: Amal Carb

Postby Bill » Tue Jan 26, 2010 5:26 pm

cheers NTT. :153

The motor in my chop is from a T140 Bonnie, so is twin carbs. The 6T (my other love) has the same (bar a few minor changes) motor as yours, so is single carb. What ignition set up are you using? Good old points or a fancy electronic thing? Prefer points myself, but that's another argument. :201 :205

u k fl ag
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Re: Amal Carb

Postby NotTriumphtwin » Wed Jan 27, 2010 2:41 am

I want to get baffles for mine to quiet it down but don't want to plug it up or smother it. The way my one pipe is bent will mean a pretty short baffle. I'm running the same points that were in it when I got it. I have a hard time setting points, most all my vehicles have had electronic ignition. I took out the points and cleaned them and haven't seemed to have any problems at all with starting or spark related problems. I would put an electric set up on there if I had one but I'm fine with the points too. I've never strobe tuned it so it's probably not perfect but starts, idles and runs fine, just doggy from (guessing here) 40 or 50 up to 80 or 90 mph. I think it's my jets for sure and want to get a 0.106 needle jet and a 230 and 240 main jet and go from there starting with the 230. I'm just gonna get the whole kit with a new float and needle, What's the difference between the all white plastic float and the black one with metal tabs? besides the obvious that i just mentioned, is one better that the other?
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Re: Amal Carb

Postby Graham B » Wed Jan 27, 2010 2:12 pm

I hope you'll notice an improvement with a 0.106 - could try needle in lowest groove (raise it to highest position) in the meantime as an experiment. Should give an idea of whether richer is the way to go.

The black floats are the latest type that are adjustable for float height (metal tabs can be bent). Shouldn't be anything wrong with your present float so save the cash for the moment

Bit tricky I'd imagine with the current pipe setup to bolt silencers on the end of the pipes. Maybe look out for a two into 1 set of pipes that sweep back parallel with the bike and don't stick out?
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