Single carb for 650SS

Brian, I have a 1964 650SS engine using an earlier cylinder head with the slightly bigger inlet.I use a single Mk 1 Amal 30mm (930) and the carburation is perfect.

What I should have done for each machine I ownis note down the settings. So, when ever I ever strip down a carb again I will keep a log.

Sorry I can't help with the detail but I can confirm that the single Mk 1 works well though I'mnot in a position to compare with twin carbs, although I'd be quite sure fuel consumption will improve with just the single.

Check out the attachment.

Excellent Phil and note the 3.00 front tyre too!

Hi Guys

Some guidance please on carb size and jetting to convert a 1963 650 SS to single carb

single Amal Mono bloc carb for 650, 1963 are 389/71 with main 320, but with this ethanol you may need a 300 main jet 3 slide ,106 needle jet . pilot jet 25 needled position 2 , well see if this works ok , as this is whats on my 650, A single carb conversion for these roads now twin carbs are just to much, and you get more mpg than twin cabs its somewhere around the 55 to 60 mpg mark at 65mph to 70mph on a long run , also try Bosch W7DTC spark plugs there better for starting and running hope this may help your anna j

Previously neil_wyatt wrote:

Excellent Phil and note the 3.00 front tyre too!

No its a 3.25 tyre front for a 650 thats whats on my 650,

Oh dear Anna, no it's not. It should be a 3.00 x 19 on the front. We have discussed this before. 1/10. See me afterwards.

Specs for almost any machine fitted with Amal carbs can be found on their website.

Anna, I said 3.00 front tyre because that's what it says in the 650 Mercury spec that Phil sent and the Mercury was the last official production slimline. Like Gordon says, we had that debate and here is the proof. That does not mean of course that the Manxman's wider section tyre as you state was not so but it wasmostly for export, The Manxmanwas not the standard bike.

But Anna, you would be right to consider a bigger main jet if running with Ethanol contaminated petrol, as the Ethanol content is 35% oxygen.

Add main jets to the replacements required when the day comes you have no fuel choice!

Brian, please let us know how you get on.

I'd also love to hear how a gentleman called Robert got on with his new carbs, to see if that fixed his problem? Perhaps we''ll never know since that thread was closed down...Grrrrrrrrrrrrrrrrr.

Anna, I said 3.00 front tyre because that's what it says in the 650 Mercury spec that Phil sent and the Mercury was the last official production slimline. Like Gordon says, we had that debate and here is the proof. That does not mean of course that the Manxman's wider section tyre as you state was not so but it wasmostly for export, The Manxmanwas not the standard bike.

But Anna, you would be right to consider a bigger main jet if running with Ethanol contaminated petrol, as the Ethanol content is 35% oxygen.

Add main jets to the replacements required when the day comes you have no fuel choice!

well then I knew there was something special about my Manxman 650 so its not a standard norton , but it sure rides nice, and really holds the road at speed round nasty corners and tractors with a muck spreader on the back ,and I do wish these farm would fit indicator or stick his arm out to tell us all know witch way there going, as one guy pulled right across me as I was over taking him but will my bike handling and its power I am still alive, and lesser bike, I would not be hear writing this , so its all down to quick thinking and my riding skills and and bluing good Norton 650 Manxman power and handling, and to top it all on this ride out round the next corner there was a spill of some kind a white greasy stuff all across the road and right on the corner and no were to go but up a grass verge with your feet out on the road to try hold you up and I just managed that one too, but it was very dangerous if a car had be coming the other way he would of lost control and hit me, so I am around to live another day, yours anna j

Hmm. It sounds like you are not really used to the hazards of riding on country roads. Do be careful. Gordon (also a tractor driver).

Hmm. It sounds like you are not really used to the hazards of riding on country roads. Do be careful. Gordon (also a tractor driver).

well around hear there not much heavy traffic .but you have to watch out for tractor drivers they just pull out from anywhere. with out any indicators or hand signals and very little care for other road users and drive there tractors like they own the roads , its just the same when there driving there land rovers or range rovers , one day we were out riding and a farmer pulled out from a petrol garage in a range rover right in front of a friend riding a BSA shooting star and knocked him off his bike he ended up a bank side, somewhat very winded and shaken , and we had the right of way on the road , one of our other friends on a Triumph T110 raced after the framer too get his reg number he came back with the number , and it was reported too the traffic police, and then farmers get way with leaving mud all over the road , but if this was a building contractor he would of been prosecuted for doing this, but the farmers gets away with it, I am not against framers its just they could be more careful on the roads and abide by the laws of the road like we have too do, yours anna j

You have to ride as if all other road users are out to kill you. Tractor drivers are no better or worse than any other road user - i.e. just as likely to try and kill you. Bear in mind that tractors don't travel far on public roads and that they will turn into obscure farm entrances. So it's better to be very patient and only overtake if you are absolutely sure the tractor is notgoing to turn in somewhere. The other killer is tractors turning left into field entrances with multi-furrow ploughs on the back. They swing out far enough when it turns to block the entire road, impaling whatever impatient road user is trying to squeeze past - usually a sporty hatchback. As for mud on the road,I don't like it either but there just isn't the manpower on a farm to try and clear it up. A 2000 acre arable farm may have only 2 workers. Sad but true.So blissful rural rides are particularly hazardous and that's where most motorcyclists are killed. You really do have to practice defensive riding. There are very few unavoidable accidents. That's the former motorcycle instructor speaking.

P.S. Very few farmers driveRange Rovers. Most have Japanese twin cab pick ups. Me? A couple of classic Land Rovers.

You have to ride as if all other road users are out to kill you. Tractor drivers are no better or worse than any other road user - i.e. just as likely to try and kill you. Bear in mind that tractors don't travel far on public roads and that they will turn into obscure farm entrances. So it's better to be very patient and only overtake if you are absolutely sure the tractor is notgoing to turn in somewhere. The other killer is tractors turning left into field entrances with multi-furrow ploughs on the back. They swing out far enough when it turns to block the entire road, impaling whatever impatient road user is trying to squeeze past - usually a sporty hatchback. As for mud on the road,I don't like it either but there just isn't the manpower on a farm to try and clear it up. A 2000 acre arable farm may have only 2 workers. Sad but true.So blissful rural rides are particularly hazardous and that's where most motorcyclists are killed. You really do have to practice defensive riding. There are very few unavoidable accidents. That's the former motorcycle instructor speaking.

P.S. Very few farmers driveRange Rovers. Most have Japanese twin cab pick ups. Me? A couple of classic Land Rovers.

well this topic about Amal jet sizes so how did we get to tyre sizes and framers tractors ! were all off topic but it was fun any way, roll on the summer, yours anna j