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N15 after complete restoring: doesnt start

Discussion in 'Other Norton Motorcycles' started by pierodn, May 5, 2018.

  1. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    Hi.
    My 1968 N15 after a complete rebuilding doesnt start.
    Engine, gearbox, transmission, all new.
    New Pazon Sure Fire I.E. setted 31 degree with new coils (clock wise setting for rear distributor ok!).
    The spark plugs have a good fire and battery full charged.
    Carbs are his stock concentric 930/7/8 overhaulled.
    I fear that the fuel doesnt go to spark plug.
    Throttle Needles are in place and go up and down.
    Pilots in place too.
    When i push the kick start the fuel spray from ticklers.
    Let me have your sugests to check the problem.
    Thanks.
    Piero
     
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  2. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    Compression, valve timing and ignition timing verified? If all are Ok the engine should start using a squirt of starting fluid into the manifolds.
    Most often firing prolems are related to ignition timing being far off. Your headers (exhaust pipes) are not blocked by rags by chance?

    If it fires using starting fluid the problem is with your carbs. You need to check the impairing factors systematically.

    -Knut
     
  3. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    Hi Knut.
    You say well!.
    But the engine is all new (flat pistons, valves, guides, gaskets, conrod shells, superblends, hea and cylinder bases skimmed, etc.).
    Valves timing as usually and ignition timing too, 31 degree before TDC (clockwise points for rear distributor).
    Exhausts well opened.
    Carbs overhaulled: pilots 25 in place, float bowls 2 mm under the top, throtle needles with clip in the center and go up and down, air way cleaned and opened.
    I cannot understand.
    Surely i am not a mechanich, but from 2012 i have rebuild 12 Norton Twins engine, all started first kick!.
    If i should play one $, i would think that fuel doesnt arrive to the park plugs, but why?.
    I really dont know where find the problem.
    I always use Pazon and never had failure.
    I have seen a lot of bikes with a very bad setting of timing, valves, carbs, that run and start the same.
    My N15 never gave any sign of firing.
    Let me know.
    Thank you.
    Piero
     
    Last edited: May 5, 2018
  4. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    Hi Piero,
    The mechanical parts appear to be up to spec. I guess you have a feel for whether compression is correct or not.

    You mention points, distributor and Pazon. N15CS bikes had a magneto (Lucas #42379B) for 1964-66 or points and coil (points housing 033066, superseded by 034049) as of later 1967 models. I guess you meant the latter.

    Have you tried disconnecting the carbs and squirting starting fluid ("starting gas") into the manifolds ? Methanol will also do the trick.
    Apply the K/S soon as the gas evaporates quickly. Make sure there is not lots of oil in the combustion chambers by flushing them with petrol. Lots of oil there may inhibit the ignition process.

    If it still doesn't start, you have either weak sparks, or your your timing is still very incorrect. A common error is setting timing to degrees after TDC rather than before TDC. If your ignitition doesn't operate on the lost spark principle, maybe timing is 360 degrees off?? Try switching HT leads.
    Are coils new as well, and did you observe both spark plugs firing?
    Have you measured voltage at the coils? Maybe the earthing is poor, creating too low voltage at the coils?
    You claim to have good sparks but assessing sparks is difficult! If sparks are weak, they will be even weaker in the combution chamber.

    Good luck!

    Regards,
    Knut
     
    texasSlick likes this.
  5. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
    I agree with Knut.

    If fuel sprays from the tickler, and you do not get a short burst of engine run time, the problem is not fuel.

    Problem is likely timing.

    Slick
     
  6. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    Hi Knut,
    thank you so much for your kindly suggests.
    The bike is a 1968 and has coils (new) and rear distributor (with new Pazon with y/b and w/b wires in the correct position on the plate clockwise setted).
    Timing is setting on the right cylinder from TDC (both valves closed) back to BTDC of 31 degree (with graduate wheel taken).
    The black wire from I.E. is on the coil that goes on the right cilynder spark plug so that the timing isnt possible to be 360 off: but, sorry, in any case i think that with I.E. is the same if you set on the right or on the left and what HT leads you fit where (or not?).
    Earth is with the red wire from battery on the frame and i assume it works.
    Coils not tested but spark is full.
    I go on to think that is the fuel.
    Let me know mire about the timing inversion.
    Thanks.
    Piero
     
    Last edited: May 5, 2018
  7. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    If you fear fuel is not reaching the plugs, put fuel in through the plug holes.
     
  8. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    Does the engine suck through the carbs? Put your hand over a bellmouth with the throttle open and turn the engine over.

    Just in case you did something wrong with valve gear.
     
  9. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    Hi.
    I will try it but first i have to remove the air filter.
    Thanks.
    Piero
     
  10. Bodger

    Bodger VIP MEMBER

    Joined:
    May 9, 2017
    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.
     
  11. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    Sure i will do it.
    Thank you
    Piero
     
    Last edited by a moderator: May 5, 2018
  12. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    Hi Piero,
    Because of slack in the chain driving the "distributor" as you call it (I still think you mean points housing and spindle), you can't simply turn the engine counterclockwise (CCW) from TDC. By CCW I mean at the spindle end where points used to be. You will have to turn the crankshaft far more - say 60 crankshaft degrees CCW - and then reverse to clocwise rotation, approaching 31 degrees BTDC.

    Another thought: Is your AAU still in place, or do you run electronic ignition advance control? If you still rely on the AAU, did you remember to block it in the advanced position when doing the timing?

    Be sure not to use both the AAU and electronic advance control as this will screw up ignition timing entirely.

    I still miss the result of a starting fluid test!

    -Knut
     
    Last edited: May 5, 2018
  13. dave M

    dave M

    Joined:
    Oct 19, 2005
    Piero, I fitted electronic ignition on my G15 and I was getting good spark on both plugs, but I found the distance between the base plate and rotor on these distributor engines is less than on a camshaft driven Commando set up. The rotor was just touching one pole on the trigger plate and shorting on one cylinder. The spark at both plugs was actually only for one cylinder as the coils were wired in series. Have a good look for any evidence of touching under the trigger plate, I simply spaced the plate out with a couple of washers and the problem was solved.
     
  14. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    Hi
    Hi Knut.
    I dont have AAU (for magneto) but the chain sproket for points.
    Thanks
    Piero
     
  15. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    Hi Dave,
    nice to read you again.
    Coils are two 6 V in series and Pazon seems to be well in place.
    I have never had problems on Atlas and P11 with I.E. on the rear points (distributor).
    Please, could you explain me better what you mean when you say “The rotor was just touching one pole on the trigger plate and shorting on one cylinder. The spark at both plugs was actually only for one cylinder as the coils were wired in series.”.
    Thank you.
    Piero
     
  16. dave M

    dave M

    Joined:
    Oct 19, 2005
    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.
     
  17. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    Hi Dave.
    I understand now.
    In any case, please: as far as i know if you invert the HT Leads there is no iussue because both plugs fired at same time with 6v coils in series and I.E.
    Or not?
    Thanks.
    Piero
     
    Last edited: May 6, 2018
  18. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    Of course you have an AAU! It's hidden inside the c/b housing. Every engine needs advancing ignition timing.
    So, if using EI with built-in advancing ignition timing, either you have to block the AAU to the fully advanced position, or remove it entirely (and probably replace the spindle by a different type of spindle).
    There are several threads at Access Norton on how to cope with the AAU.

    -Knut
     
    Last edited: May 6, 2018
  19. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    Hi dave M,
    Why do you refer to "distributor engines"? Neither G/N15, P11 or Atlas/650 was ever fitted with a distributor. Maybe the 650 had the 18D2 distributor prior to 1962 - that I haven't looked up, but later on it was either magneto or points+coil.

    Cheers,
    Knut
     
  20. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    Hi Knut.
    Sorry but i dont understand what you mean.
    1968 N15, 1968 Atlas, P11 and first 1968 Commando have all the same rear points system that i name distributor.
    If you want to fit the I.E. instead of points you remove the points plate and the AAU.
    The spindle that remains hidden with the sprocket into the timing works great with the I.E. rotor.
    Thanks
    Piero
     
    Last edited: May 6, 2018
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