Hi
I’ve just finished rebuilding a 1952 Model 7 Plunger and I’m having trouble starting it. Basically not a hint of any firing at all.
I’ve had the magneto rebuilt and have sparks at the plugs. There’s fuel to the carb and I’m reasonably confident with the timing. Disconnected the magneto kill lead.
I would be grateful for the base settings for the pilot and air screws, please.
Plus any other advice on starting
Thanks
Doug
Has it simply oiled the…
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Old bikes usually need help…
Old bikes usually need help with fuel supply to start. Some will be happy with full choke but many need a tickle and like the fuel to be dripping off the bottom of the carb. Do it outside the garage,and keep a fire extinguisher near the door. If really nervous invest in some fireproof undies, ---there has been occasions-------.
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Hi Doug - What is your…
Hi Doug - What is your starting drill ? My 1950 ES2 generally starts in a couple of kicks . Fuel on - full choke (air slide closed ) if cold . Tickle float chamber 3 quick pushes . Spark nearly fully retarded. The 276 has an “ easy start “ screw . Turn this to raise the slide .
Now you are ready to kick . Here is the important part . Slowly bring piston to top of compression stroke then ease it just past TDC using the valve lifter . Now give a long full swinging kick. By starting the kick just past compression you will get the mag spinning faster to produce a better spark . If you flood it , turn fuel off and pull valve lifter and evacuate cylinder by kicking through rapidly several times .
Another technique that is some times used in desperation is hold valve lifter open and kick rapidly to get crank spinning then pop lifter closed. Hope this helps - Cheers -Richard
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Have you tried...
... a squirt of easystart? If you have a spark that will usually get it firing and it will often pick up on petrol after the first few bangs. If it's still silent I'd be looking at plugs / mag.
Richard's technique is fine for singles but for twins I always found it best to get it on compression then put my weight behind the kickstart which would bounce it over the next compression.
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amal per mono bloc and starting
hello Now you say you have a good spark at both plugs but is the ignition set up the right way around as there is a right way and wrong way of setting up the magnetos and amal per monobloc and you need to check the throttle carbs and choke cables are working right now for magneto check that the points are looking upwards and the ignition lead is the one nearest to the battery box and check the timing by top dead centre on firing stroke to find this remove the rocker covers to check if all the valves are in the closed position now with a good timing disc fitted to the drive side of the engine set at zero and make your self a good pointer I usually use one of the barrels studs and its nut to hole down the pointer and with a pencil you can feel the piston moving downwards if you turn on the engine sprocket nut turning the engine backwards to 30 degrees and you see where the points are witch buy now they should facing upwards and the point cam at 5 o, clock now rock the crank back and forward to see the points open and close this should give you some idea where the points are firing and what degrees there firing at now to set the points you then have to undo the ADT and set the point at 30 degrees before top dead centre fullly advanced so its mean opening the ADT bob weights and punting a smal bolt to jam them open so then you can set the timing once the timing is set so the iginotion lead that the fathest away is for the drive side cylinder or left hand side cylinder ocne all this os done and then move on the carbuettor you need to check thigs like the needle size the cutway side is the right size a 6-3 and the needel is in the right notch two down your air srcew set at one and a half turns outwards and all put back together now turn on fuel and tickel ones or twice yuo should see a small amount of fuel check you have the right plugs fitted and then try starting the engine most model 7s and model 88s start easy if everthing in order and set up right way yours anna j
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Compression
Thanks, so how do I decide If it’s on compression?
From these comments I think I’m maybe a bit stingy with fuel.
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jet sizes
hello model 7 and model 88 of 1954 with pre-mono-bloc jet size should be a 170 or 180 pilot jet a 25 needle size D and a 106 needle jet try fitting a stay up float as Ethernol erodes brass over time and fitt neoprene Gaskets and fibre washers you find online IBHSLtd Boilerhouse Supplies for Neoprene gasket sheets or you can get them made for you by these people and they do all types of sealants You did not know I have a passion for steam locomotives of all sizes now have fun yours Anna j
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It does sound as if you have…
It does sound as if you have not flooded it enough. For starting, most carb settings (needle, slide, main jet) are pretty much irrelevant. The pilot circuit does most of the fuel supply. You hardly need open the throttle at all. If you open it too much when you kick start there will be too much air and not enough fuel sucked up through the pilot circuit.
When it catches, advance ignition quite quickly and open the throttle smoothly but not too fast. Blipping the throttle isn't a good idea because there is no accelerator pump. Open the air slide as soon as you can.
It'll all become second nature very soon. But they all seem to be a little different, and a newly acquired bike can sometimes be a bit awkward at first.
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I have 2 racey singles with…
I have 2 racey singles with seperate float chambers . They both demand loads of fuel to start and run ragedly for a few seconds till they clear the excess,They both have larger than usual (for the capacity) valves and intake systems .The air speed thro the carbs must be very poor at kickover speeds,so pulling fuel thro the pilot system just does not happen. Flooding is essential if a heart attack is to be avoided.One learns to hold the throttle open till things settle. Your bike should not be this extreme but sometimes thats what it takes.
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Has it simply oiled the plugs? When my single misbehaves, it's usually sorted either by a fresh plug, or by doing my best to clean the one it has.
Pilot screw usually starts 1 1/2 turns out.
Do you have other or previous old bikes?
Usually on mine with manual magneto, assuming it was timed properly when on full advance, is to retard just less than 1/4" on the disc on top of the lever, and bring it forward a bit as soon as the engine catches.