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PVL Coils

Home Forums TR3OC Members Forum PVL Coils

This topic contains 9 replies, has 5 voices, and was last updated by  Tim Harwood 1 year, 1 month ago.

  • Author
  • #5593

    Mike steer

    Having massive problems getting my T160 started. Bike back fires after several attempts on the starter button, back through the nearside exhaust. I’d like to think I have tried everything. There are PVL coils fitted along with a Mk3 Boyer. Does any one have coil testing values they could pass on to me so I can do a thorough check as possible on the primary and secondary aspects.   One reading is giving 2.2 ohms on each coil. However what I have done in the list below you might say that the coils are fine if ‘this and that’ is happening. The only thing I can see clearly is that I’m only getting 9.7 volts at the Boyer Ignition box when I crank the engine over.  Is it right that the BB ignition box needs 12v to make it work? However it won’t start on the kick start, after several kicks I get a pop back through the carb. Could it be the Zenor Diode or rectifier???  How can I check these? I was hoping not to right the list below but it will give you an idea of where I am with it all.

    Brand new battery (Yuasa YTX14L-B5) 200 CCA.  Supplier has checked and all ok. 12.4 volts at battery and into coil 1

    Carbs stripped x2, (pilot grub screws removed, carb cleaner, air line, all orifices clean)

    Float heights checked. Stay up floats added.  Viton tipped needles several years ago.

    Fuel tank flushed

    Plenty of fuel when carbs tickled

    New ethanol resistant fuel line

    Earth wires on frame, engine and in headlight removed cleaned and replaced

    Plugs changed

    Kill switch checked, cleaned.  12+volts evident

    New fuel

    New K&N air filter

    Spark’s at plugs cranking engine over on the starter

    Black/white, yellow/black wires touched on Boyer which sparks the plugs.  This apparently indicates that the Boyer is probably OK (their words)

    Timing at stator plate spot on.

    Its come to a point now where I can’t see the wood for the tree’s so any suggestions would be most grateful.






  • #5594

    keith berry

    Flat battery mk 3 boyer needs more umph should be near 14v and use the kick start first

  • #5595

    keith berry

    I have a 19amp battery fitted and that needed to be kicked over first after that its fine, also alternator needs to be checked or a new high power unit fitted

  • #5596

    keith berry

    Oh and fit a new reg/rec modern

  • #5597
    David Lord
    David Lord

    I’m not sure about the mk3 Boyer but certainly some versions will not work on under 10volts.  You can eliminate that by either using another battery in parallel with jump leads to increase the cranking capacity or by connecting the Boyer only to a separate battery/supply so it’s supply voltage is not affected when you crank the engine.  What starting procedure are you using? It’s very easy to get into a buggers muddle when an engine won’t start on the first 2 or 3 goes I.e. It floods, battery voltage drops etc making it less likely to go! You did say in a previous post that it did run so I do still suspect battery voltage is your problem?

    • #5599

      Mike steer

      Dave thanks for replying again.  Yes it did start.  I did squirt some fuel into each cylinder though the night before so it was that residue the next morning that fired it up for a while. To me this all points to fuel starvation if it starts like that but I feel I have done all I can in that area to eliminate it.  The only thing I haven’t taken out of the carbs is the welch washer in the main body.  I’ve had grub screws put into the pilot jet area, I took these out and everything was clean. The pilot holes were all clean. Checked all the jets all clean.  Used carb cleaner and comp air, Flushed the tank out,  Carbs flood nicely on the ‘tickle’.  The only other thing that points to fuel starvation is when I take the plugs out (again) they are dry and not soaked in fuel as you would expect after flooding the carbs 3-4 times.  As I said above I am only getting 9.7 volts going into the BB ignition unit from the kill switch wire yellow/white to white on BB.

      Just tried it on the kickstart again, nothing.  A small pop back through one of the carbs.  I have a brand new Mk4 BB system on my mk1 R3 Im going to pull it off and fit it on the T160 and see what happens.  That way I can eliminate plenty of potential problems

  • #5598

    keith berry

    Try a set of jump leads of your car? 👍

  • #5600

    keith berry

    Flat battery, try supplying the coil off the batter direct

  • #5612
    john smallwood
    john smallwood

    I would suspect that you’ve timed the Boyer on the exhaust stroke rather than the compression stroke. I did that once and it coughed and popped but obviously wouldn’t run.

    Time it on the T/S cylinder according to the Boyer instructions (screw head visible through the little hole on the backlate at 38deg BTDC but make sure its on the compression stroke (Bothe valves are closed)

    Fingers crossed ….


  • #5639

    Tim Harwood

    Mike – what are your pilot screws set to?

    I tuned mine (T160) a while ago, and they were around 2 turns out +/- 1/4 turn for best running.

    However, more recently I did some work on the rocker box, re-torqued the head and needed to reset the tappet clearances.

    Upon going to restart, it would barely fire on one cylinder and certainly wouldn’t start, even using the choke.

    Eventually I reset the pilot screws to 1.5 turns out and bingo she fired up pretty much straight away.

    A bit more trimming and she runs really nicely with the pilots 1.25-1.5 out depending on cylinder.

    Why the difference just because of a tappet reset, I cannot fathom or explain?.

    I have done a lot of work on 2 stroke carbs, and quite a few 4 strokes and never encountered this type of sensitivity to the pilots before.

    Just an idea – try your pilots at 1 or 1 1/4 turns out and see what happens???

    HTH – p.s. I run a Trispark on mine with 3 6v coils and ballast resistor.  Cannot use kicker as I had 2 new knees fitted a couple of years ago.


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