Pick Up Coil Air Gap?

Discussion in 'Technical Help' started by Pike, Sep 29, 2019.

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  1. Pike

    Pike Member

    Sep 25, 2018
    54
    18
    Bristol
    Hi.
    whilst renewing the pick up coil on my 12k mile 2006 Bonnie T100, I measured the old ones air gap. I could only get a 0.229mm feeler gauge between the coil and rotor pip. Spec is 0.8mm.
    What does too close a gap do?
    the new one is installed and set at 0.813mm nearest feeler gauge i had.
    I have also replaced the single coil and HT LEADS.

    Had the common fault of backfire and single cylinder running before dieing completely. Re starting after leaving to cool for a bit but rinse and repeat limping home.

    the bike now starts better and warmed up smoother but need to ride to make sure 100% sorted.
     
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  2. Callumity

    Callumity Elite Member

    Feb 25, 2017
    1,932
    750
    Nr Biggar
    This a bit of Goldilocks story........

    Too big is not too hot because the magnetic field/trigger can be weakened causing a misfire. The original bikes were set at 1mm and .8mm was the revised figure being ‘close enough’ but not ‘too close’.

    Too close is really about risking contact and physical damage or a foreign body in the gap (possibly transported in oil?)

    It sounds like you have gone full Irish replacing ignition AND pickup coils AND HT leads (to be sure, to be sure, to be sure). With the single coil 360 degree twins the symptoms can be harder to isolate than the twin coil 270 twins. Personally, having replaced my 2005 ignition coil with a sub 3,000 rpm misfire I suspect your entire problem lay with the pick up. The ultra fine windings are prone to fracture and before total failure they work until the coil is hot enough for expansion to open the gap in the winding.......and close when it cools.
     
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  3. Pike

    Pike Member

    Sep 25, 2018
    54
    18
    Bristol
    Thanks,
    I guess someone has been in there before me. I can't believe such a small air gap would have been set at the factory?
    replaced coil n leads with TTP Blueflame anyhow, as relatively cheap components and should pep things up a bit?
     
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  4. Callumity

    Callumity Elite Member

    Feb 25, 2017
    1,932
    750
    Nr Biggar
    I am a bit of a marketing cynic about ‘hot’ ht leads etc.m since the coil has far more influence. Plugs and gaps......it goes on. Opening inlet and exhaust DOES make for a worthwhile hike in mid range torque.
     
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  5. Pike

    Pike Member

    Sep 25, 2018
    54
    18
    Bristol
    Yeah..know there are lots of performance mods I can do but purpose of adding this bike to the stable was in keeping it standard. Hope the fixes have sorted it. Before buying a RE Continental 535 the Bonnie was favourite ride. Now the RE.....super grin factor.
     
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  6. Pike

    Pike Member

    Sep 25, 2018
    54
    18
    Bristol
    I have test ridden and still have the problem. Retraced all previous work. Even swapped HT leads over but still the same.Still think it's electrical ignition. Checked for broken wires and thoroughly cleaned all connections.

    New pick up coil is 560 ohms cold and 720 ohms engine hot. New coil is measuring 1259ohms hot and same room temp. Haynes manual quotes 15k ohms?

    Could it be the ignition igniter unit as can't think what else in ignition circuit it could be?
     
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  7. Callumity

    Callumity Elite Member

    Feb 25, 2017
    1,932
    750
    Nr Biggar
    The only way to test the igniter is by substituting a known good one. Is there any visible sign of the seat pan crushing the igniter or connector block? That is a known cause of ignition gremlins.
    My own igniter certainly gives no signal to the rev counter. It was initially intermittent then died totally so I rigged a live feed from the ignition coil to the instrument and all is superficially well.
    Do NOT waste money on the £320 OEM igniter. Triumph Twin Power supply the same item with a better map for £234.
    https://www.triumphtwinpower.com/fire-starter-performance-igniter-unit.php

    Btw your resistance figures all sound ‘in the ballpark’.
     
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  8. Pike

    Pike Member

    Sep 25, 2018
    54
    18
    Bristol
     
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  9. Pike

    Pike Member

    Sep 25, 2018
    54
    18
    Bristol
    Yeah.just ordered igniter from TTP. NO signs of damage to existing igniter but chatting to the very helpful guy at TTP he says he is selling a lot of replacements for Bonnies of my vintage. Also spoke to my garage guy I use for MOTs (whilst booking in another bike) and he confirmed your advice re resistance figures. If the igniter doesn't cure it then plenty more head scratching. I will keep you posted and thanks very much for your valued advice mate.
     
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  10. mpllineman

    mpllineman Senior Member
    Subscriber

    Feb 12, 2018
    678
    250
    Pearl,Ms.
    This thread certainly came along at the right time for me, I am having the old single cylinder Scrambler. Mine is also a 2006 model as well. I am at the stage in my diagnosis of either the pick up coil or the igniter. Thanks for the tip on where to get the improved model for less $! I have to work again today, but I will definalely will be testing my Pick up ASAP. From my online investigating, this seems to be the more likely culprit, but we'll see. I'll post when I find out!
     
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  11. mpllineman

    mpllineman Senior Member
    Subscriber

    Feb 12, 2018
    678
    250
    Pearl,Ms.
    I have read that the plug in connection for my pickup coil can be a real pain to access. Where is it?
     
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  12. Pike

    Pike Member

    Sep 25, 2018
    54
    18
    Bristol
    Good timing th
    En.
    Yeah On mine i can't see it's fueling issue as fine when cold all be It briefly. Lovely bikes when running fine. Hey ho...a good challenge for us all
     
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  13. Pike

    Pike Member

    Sep 25, 2018
    54
    18
    Bristol
    Good timing th
    En.
    Yeah On mine i can't see it's fueling issue as fine when cold all be It briefly. Lovely bikes when running fine. Hey ho...a good challenge for us all
     
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  14. Pike

    Pike Member

    Sep 25, 2018
    54
    18
    Bristol
    The t100 pick up coil connector is under the tank/seat frame. Access by removing rh side panel trace wiring from alternator cover. On mine it has 2 wites. A blk and red. It's a tight squeeze to uncouple but be patient and don't yank too hard on the wires! Good luck.
     
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  15. Pike

    Pike Member

    Sep 25, 2018
    54
    18
    Bristol
    A bit more info. Suddenly wondered if it was a battery issue. Swapped out but no difference. A desperate measure but you never know.
    So,gone back through my servicing record and the fault first appeared after I had done valve check but not as severe and had ridden with no issues until now. Had to replace 7 out of 8 shims. From my notes am absolutely certain everything went back together correctly and mechanical timing is correct. I have experience doing valve checks working on mainly jap multi cylinders Inc the R1 5valve/cylinder head so the Bonnie much simpler...however could I have missed something?
     
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  16. Callumity

    Callumity Elite Member

    Feb 25, 2017
    1,932
    750
    Nr Biggar
    Connectors. There are a couple you might have overlooked. One buried under tape under the tank and one inside the headlamp shell.

    Other possibilities. Ignition switch contacts. They could be an issue and disassembly might reveal arcing but a clean up and application of silicone grease (Di-electric) will do no harm on a ‘mature’ bike. Outside chance your side stand switch might be sticking. Likewise benefits from a clean up, wiggling with a WD40 blast and re-grease.

    Watch the birdy. Does the rev counter die when the misfire occurs? That would suggest the problem is with the trigger I.e. igniter or pick up rather than downstream of the ignition coil +ve tab.
     
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  17. Pike

    Pike Member

    Sep 25, 2018
    54
    18
    Bristol
    Nope...rev counter does not die when misfire and subsequent stall occurs. When checking valves I did not disturb any wiring in headlight. What do the connectors I might of missed do under tank?
    If mechanical timing was out would fault occur from cold?
    Will get the deoxit out and attend to parts you suggest. Starting week of night shifts now so limited time. TTP igniter will arrive tomorrow so try and fit that then. Silly question. How does the plastic stud holding the r side of the igniter come apart?
     
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  18. Callumity

    Callumity Elite Member

    Feb 25, 2017
    1,932
    750
    Nr Biggar
    Under Tank connector is just a joint in the loom.

    I am beginning to suspect you have a duff igniter. From recollection the stud does not come apart. It just locates the igniter and prevents rotation. It is non critical so use a bolt and locknut if the stud cannot be transferred......but I suspect the TTP item will come with ‘destructions’!
     
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  19. Pike

    Pike Member

    Sep 25, 2018
    54
    18
    Bristol
    Yes...I hope it is the igniter. Seems funny how started happenning after valve adjustment though but probably a coincidence. Will have more time next week so if igniter doesnt cure it will go back in there and double check mechanical timing and valve clearances The last time it ran well for 20 or so miles a couple of weeks ago it was a joy to ride so am dobtful it was the valve check work. Will update once new igniter installed.
     
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  20. mpllineman

    mpllineman Senior Member
    Subscriber

    Feb 12, 2018
    678
    250
    Pearl,Ms.
    Thanks for the info! This has, or rather is, a frustrating problem. I guess it is due to the fact that in all the bikes I've owned, this is the real first electrical problem like this. I know the old Triumphs were famous for their Lucas electrics. And just to add that I replaced my battery, which was just under the specs. Also mine has no fueling problems. Best of luck with your igniter and I'm hoping for the same with a new pickup coil.
     
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