Hitchcocks Forum

After about 10 miles of fairly fast (about 65mph) cruising on the motorway on my 612, it starts to miss a few beats, then the misfiring progressively gets worse even at lower speeds. After 30 minutes or so rest, it runs fine again for another couple of miles before it starts misfiring again. The same thing happened about 150 miles ago, when I assumed it was a shot condenser (the points having shown some erosion). After changing the condenser and points on that occasion, all seemed well, until today when it kicked off again. Incidentally, fuel flow seems ok, the float bowl is clean as a whistle and I have flipped open the tank cap in case of airlock. Also I have tried different plugs. So I am thinking it’s either a faulty coil or yet another faulty condenser (can a bad coil ruin a condenser?). It’s the original standard coil as fitted to the Sixty5 which has now done 8000km. There is some MILD blue sparking visible between the points when revved (they are still “clean”) and I get a blue spark at the plug which will jump across about three-sixteenths when kicked over, and it still starts on the first kick. And the coil doesn’t feel warm. So what does the panel think? Does it sound like just another shot condenser or a duff coil (or both)?

----------Which is the cheaper option to change ??-------- OR--have you another coil, known to be ok, which you can substitute ??--------- This year the HT coil on my 2005 Classic 500 went open circuit whilst out on an evening run !!------This is a "genuine " Indian Lucas item and was v. hot to the touch just after coming to a halt.(7,500 miles !!!) Electrically it's the HT Coil that creates a spark (collapse of magnetic field around the coil windings) but it's the capacitor(condensor) that multiplies this effect, both when the points have opened. They are sensitive to heat, moisture, vibration and poor/bad electrical jointing. The HT cable and plug cap can also give similar problems ----- try a cable with the solid copper centre and look at the route it's taking. I would just check what plug type is actually recommended for the 612 as you will have higher temps. and pressures compared to a standard 500 bike----hence a different plug, maybe ?? Also,give some thought to fitting the smaller-bodied PVL coil which is a better performer all round---IMHO...Then after breakfast -----------------------------------------------LoL !!

Thanks for the input Alan. Yes, it’s the correct plug as recommended by our hosts for the 612 (B8ES). I intend changing the condenser (again!) and perhaps a new plug cap, before I resort to trying a new coil (which if I do will be the PVL). But I am wondering the likelihood of it being the coil?

You could try asking an automotive engineer to check-out the coil for you but it does sound like a temperature-related fault which is a bit difficult to replicate on the bench.

Hi Barry

I had the same problem with my 65 last year. Changed points and condenser due to excessive arcing but no
improvement. Turned out to be duff coil with shorting primary coils causing high current flow . Check discharge
rate on ammeter with points closed to give you a clue as to whether it is excessive.

Hope this helps.

Regards

Mick H.

I am trying a new condenser this weekend (then the plug cap) and of course, will get a new coil if there is no improvement. Incidentally, the coil doesn't get hot when the problem occurs, I don't know if this means anything though. And regarding the ammeter as you suggest Mick, it seems to behave normally - ie, its dead centre when the ponts are closed, so does that eliminate the fault that you had?

Hi Barry
I think you would normally see a discharge of 2-3 amps. When after a few miles the fault occurred on mine the needle nearly went off the scale with ign on and points closed. Local RE dealer took one look and changed coil £105 ouch! Fixed it though.
Atb Mick

Hi BARRY--- I think that should be the ammeter is on ZERO when opened. When the points are closed electricity is actually by-passing the capacitor and flowing from the HT coil, via the points to earth, tus energising the primary windings. If you are using the "Ammeter flick" method of starting your bike then that "Flick" is the points having just opened thus showing you the piston is just over TDC from the compression stroke and is now on the power stroke. MICK----what on earth was that £105 for ??

HI Alan
Coil and lead £40 , 1hour labour£48 plus vat. They've gone bust now wonder why?
Mick

----------Crikey, mate!!! all the more reason to try the DIY methods. I know of a company called Bluestone Engineering here in Shropshire, (run by a v.good chap known as Alan R, incidentally)..who charges by the tea & Chokky bikky for labour rates. I use them all the time !!.......... Forum members ALWAYS welcome..............