N15 after complete restoring: doesnt start

I would switch plug wires before doing anything else. It's easy to set timing 360 degrees off. DAMHIK. It's the easiest and quickest diagnostic you can do.

Hi.
I dont understand what you mean with 360 degree off.
Both sparks have fire together every 360 degree so that is not important what the HT lead is fitted where.
Thanks.
Piero
 
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You are correct. If it is a wasted spark system it should not matter if you time ignition to the compression or the exhaust stroke, so that is not your problem. With a magneto it is an easy mistake to do and diagnosed/corrected by switching the plug leads. So my suggestion was not helpful.
 
Thank you, Piero. You confirmed the engine had an AAU which you removed. That's what I wanted to know.

Now to the question of timing .....
 
Knut, I referred to the points housing as a distributor because that is what Piero called it and I didn't want to confuse things with different terminology. It is difficult enough diagnosing technical problems in your mother tongue, let alone a second language.
 
Hi.
About the carburators, 930/7/8 old Amal, the needle jets 106 dont have the two holes.
I can change with two new with holes, but i dont think that this is the problem.
Thanks.
Piero
 
Hi.
About the carburators, 930/7/8 old Amal, the needle jets 106 dont have the two holes.
I can change with two new with holes, but i dont think that this is the problem.
Thanks.
Piero

You are most probably aware that your 'older style' Concentric carbs will have a shorter jet holder and main and needle jets, and the pilot jet #25 screws into the bottom of the carb body. There is no pressed in pilot jet like the more common later Concentrics.
 
You are most probably aware that your 'older style' Concentric carbs will have a shorter jet holder and main and needle jets, and the pilot jet #25 screws into the bottom of the carb body. There is no pressed in pilot jet like the more common later Concentrics.
Hi.
Yes.
I have the shorter jet holder and the pilot jet 25 screwed into the body.
I would only say that the needle jets 106 dint have the two holes like later.
Thanks.
Piero
 
Piero, with two 6volt coils wired in series both plugs spark at the same time every revolution. One will be firing the mixture in the left cylinder for example under compression the other will be sparking on the right cylinder on the exhaust stroke- this is called ‘a wasted spark’ because it achieves nothing. On the next revolution of the engine the right cylinder will be on compression and will fire while the left cylinder will be on exhaust and will not fire. This type of ignition is essentially a two stroke which fires every time the pistons reach near TDC. Since there are two triggers on the base plate if one is short circuited you will see spark at both plugs but you are actually trying to start a single cylinder 375cc. Look under the base plate and see if the rotor has been touching the solder joint when it roasted, if so file a bit and space the plate away from the rotor.

Hi Dave.
I have fitted the two shims in the rear of the IE plate.
Sorry, but nothing happened, the bike still doesnt start.
Good fire to the soark plugs.
What i must do?
Will change carbs and IE!!!
Thank you
Piero
 
Just wondering, if this is the same bike that sprays petrol from the carb when you kick it over, could the valve timing be way off? Intake valve overlap off enough that the piston is pressurizing the carburetor on compression more than would happen with normal overlap? Seems to me like most other suggestions are sort of working around the margins of your problem. If the engine is getting petrol (starter fluid spray in carbs) and the timing is off even a couple of degrees, the bike should fire, maybe badly and not steady, but you should at least get some backfiring and banging. The fact that you get nothing makes me think something more key than bad carburration or slightly off timing is your problem.
 
Just wondering, if this is the same bike that sprays petrol from the carb when you kick it over, could the valve timing be way off? Intake valve overlap off enough that the piston is pressurizing the carburetor on compression more than would happen with normal overlap? Seems to me like most other suggestions are sort of working around the margins of your problem. If the engine is getting petrol (starter fluid spray in carbs) and the timing is off even a couple of degrees, the bike should fire, maybe badly and not steady, but you should at least get some backfiring and banging. The fact that you get nothing makes me think something more key than bad carburration or slightly off timing is your problem.

Hi.
You say "more key than bad carburration ....".
Please, what you mean for "key"?.
Thanks.
Piero
 
Hi Piero
Sounds like Bodger is saying that something is key to problem ie the main problem and everyone is skirting around it, the thing that sticks out that it is highly unusual that the fuel sprays from the carby, I am assuming that is from the carb inlet not the tickler, if so this to me suggests wild valve timing/wrong valve timing!
When I start my Manx in cold weather at low speeds it throws out fuel vapours but clears up once you stick the revs into it, remembering Manx Nortons have big valve overlaps, but this is not straight fuel being sprayed out, so in your case maybe it is valve timing issue as suggested by Bodger???.

Burgs
 
Hi Piero, Burgs has correctly translated my poor English which may also have suffered from having a drink on the way home from work. I apologize for not being more clear. I meant that it seems logical that there is a bigger underlying problem than ignition timing or carburation. I'm just thinking that when ignition timing or carburation is the problem the engine will usually at least fire poorly. For example if you had access to some starter rollers, and spin the engine over and spray some starter fluid in the carbs, the bike should at least fire ocassionally or at least backfire. (If you try this I suggest you do it outdoors with a fire extinguisher nearby). If that experiment doesn't get the engine to run even badly it suggests a bigger, underlying problem, like valve timing. I hope this is more clear. I envy your ability to write in a second language. Bodger
 
Piero, sometimes the rotor of the electronic ignition can slip on the taper of the shaft, this can happen even when kicking the engine over, I suggest you recheck the ignition timing.
 
Fuel spraying out of the tickler sounds like incorrect valve timing. The piston is coming up and the valve closing is too LATE to stop pressure from being driven backwards through the port and pressurizing the carburator. With the slides down, the pressure goes through the idle jet passage to pressurize the bowls. If the float's needle is seated then the pressure pushes out of the bleeder...

You need to pull the timing side engine cover and make sure your camshaft and crankshaft sprockets are the sycronized properly. It sounds like you are off by at least 1 tooth...
 
Hi All,
and thank you so much for your kindly help that i have very very apreciate.
To day i have changed the Pazon (rotor well hold into the shaft: dont slip) and resetting timing 31 degre BTDC: the bike didnt start the same.
To morrow i will change the carbs.
About valve timing i have the pictures of the engine rebuilt: seems to me well syncronized but i will check tomorrow.
What can i say more?: seems to me that the engine has less compression of my Atlas and P11.
Thank you.
Piero
 
Very interested to know what you discover. Poor compression could be a symptom of a valve timing problem. Then again it could be something else. It is strange that the bike seems to have so little compression. Might be worth putting a compression gauge on each cylinder. If the compression is significantly less on one side than the other that would tend to disprove the valve timing hypothesis. Incorrect valve timing would affect the compression equally on both cylinders.
 
Piero also check that the wires to the trigger plate on the electronic ignition are the correct way round. They must be connected to the correct pole - they are colour coded
 
Hi.
To day i have removed all the timing gears, sprokets and chains.
They seemed to be well in place.
Mounted all again, resetted the Pazon I.E..
Tomorrow i will find to start again.
Good spark , good compression, good luck!.
Piero
 
Tomorrow i will find to start again.
Good spark , good compression, good luck!.
Piero

You still need the third part: fuel, which comes back to your original issue of fuel spraying from tickler when kicking.
Hopefully after kicking this time your sparks plugs will show wet with fuel.
And success!
 
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