Starting A10

[cbrosolo]

Hi all, I’m new to this forum and have just purchased a Super Rocket 1958, I had the bike running for a few minutes, but then could not restart it, I removed the plugs and they were dry and I had spark, after 1/2 an hour of kicking it and tickling the carby it would not start and the plugs were still dry, could it be the Amal Concentric carby problem, or weak spark, or is there a sequence I should follow when starting it, any help for a novice would be greatly appreciated, thank you

[Catz]

Longshot, but have you used all the juice in the right hand side of the tank and need to switch over to the left side tap? JAT.

[cbrosolo]

Thanks for your reply, I had both fuel taps turned on, even tried a bit of “start ya bastard”  ??

[muskrat]

G'day cbrosolo 
Is it an old Mark 1-1.5 ? A problem with the pilot circuit is crud can gather in the junction (under the brass welsh plug). Ultrasonic cleaning of the carb is the best way to get all the capillaries clean. The float needle may be stuck closed, I'd recommend a new "stay up float". https://amalcarb.co.uk/optimising-mark-1-concentric-fuel-levels
One of the problems I found with using a concentric on an alloy head was the intake angle and fuel height in the bowl. I had to set it very low to avoid the float hitting the roof and holding the needle open (flooding).

Now get over to Introductions and give us your story.
Cheers

[limeyrob]

I have exactly the same problem.  It is as said, very likely the idle circuit blocked.  Try everything you can to unblock it but it all else fails (which is where i am) you can drill the jet a bit bigger and screw in the threaded pilot jet. I'm waiting on the 5BA tap and new jet.
The blockage will be under / behind the pilot jet at the bottom of the hole for the pilot air screw, its just about impossible to get to.  The hole is so small a compressor won't clear it.
https://www.youtube.com/watch?v=tArRwSnAu0s&t=558s

[cbrosolo]

Thanks for the reply's, I think I'm going to go with a new Amal premium carb, I can get for a reasonable price, as I think the slide is worn out on this one as well, at least I will be able to eliminate 1 x potential problem.
 Also a new one will be shiny, LOL.
 

[muskrat]

G'day cbrosolo, (still working on an Aussie nick name, how does solo sound?)
I threw a premium on the 51 A7. Best thing I've ever done.
Just be aware of the float/fuel height thing.
I have a modified bowl screw to check the fuel height. Your welcome to borrow it.
Cheers

[cbrosolo]

Thanks mate, my nickname for 50 years has always been “Bros”   I love my English bikes, so I must love oil leaks, thanks for the offer of the screw, I’ll post when I get the new Amal 👌

[muskrat]

G'day Bros.
Funny how a nick name sticks. 99% of my mates for 45 years that only know me as Musky (short for muskrat). Given to me by the club Pres for the amount (pints) of muscat I drink!
What size concentric? Should be the size of the inlet port and don't forget a tufnol spacer.
Cheers

[Swarfcut]

  Plugs out and a slug of fresh fuel down each cylinder should get it to fire enough to run on a wider throttle. Fade out on tickover is a problem with the  carb idle circuit. Regard early AMALS as 2 in 1 Carb, the "idle carb" is problematic with small drillings subject to blockage from deposits and corrosion.

 Flooding with the old fashioned tickler disguises these failures, plenty of fuel into the inlet tract and choke on and just a touch of throttle will normally do it.

 The concentric design attempts to improve this idle circuit, but I doubt any success claimed.

Swarfy.

[cbrosolo]

G'day cbrosolo, (still working on an Aussie nick name, how does solo sound?)
I threw a premium on the 51 A7. Best thing I've ever done.
Just be aware of the float/fuel height thing.
I have a modified bowl screw to check the fuel height. Your welcome to borrow it.
Cheers

Hey Musky, can you send me a picture of modified bowl screw, so I can check what you've done? , I may make one,
 Regards Bros   

[limeyrob]

I had trouble starting my Road Rocket after a rebuild. 2 things fixed it and it now starts first or second kick.
Clean and check the mag and make sure its sparking well at around 80 rpm. I did this on the bench with a hand brace and stop watch and mine wasn't, in fact it was hardly sparking at all.  It sparked great when I span it by hand, but not at a steady speed and not when a bit retarded for starting. I ended up raiding the parts bin and building a better mag.  I made a wooden dowel to fit in the earth brush holder so I could time the mag on the bench then lock it in place for fitting.  Saved a lot of time.
That didn't explain the dry plugs so i stripped the Concentric.  Idle circuit was blocked solid and its near impossible to clean so I drilled out the pilot jet under the pilot screw to .5mm so I could poke it though.  I got a 5 BA tap and cleaned up the tread for the alternative pilot jet fitting and got a 020 jet and screwed it in.
Total fix , good starting and clean idle.  The tap was about £5 and the jet about £5 so its £10 fix.
I believe the screw-in pilot jet needs good suction and the A10 has this with a single carb, on twin carb set ups its less effective.  Odd becuse the fuel path is the same length, but with the screw-in jet the jet is at the start of the passage, with the press-in its at the end. A mystery.

[muskrat]

G'day Bros.
I thought I had a pic of the drain screw. I have a pic of it in action. just pick up another screw fill the under side with JB weld then drill and tap 1/4 BSP. Get a hose tail and screw in, attach clear tube and open the tap. fuel height will be seen.
Cheers

[limeyrob]

With care, and no naked flames...you can take the bowl off and hold it then turn a tap on and it will fill to its level. Its a useful way to tilt the bowl to match the inlet angle and see where the level settles. I got a Concentric "StayUp" float so I could bend it to get the level up a bit.
(Who ever thought of that name for a carb float? No explanation for a line on my card statement with "StayUp £15" would be believed) 

[cbrosolo]

Hi Musky and others, I put the new Amal carb on and it now starts 2nd kick from cold, bit harder to start when i'ts hot, but I found giving it full throttle for the 1st kick then about 1/4 throttle 2nd kick gets it going. I'm still nervous about a long ride , worried about the magneto letting me down, so I will stay around town on it till I can trust it. If it tops for no reason again, it must be the magneto???  can't be anything else?//, as now has the new carby. Regards Bros