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Author Topic: New Charging system sorts out Backfire - why?  (Read 1117 times)

jonathanrowley

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New Charging system sorts out Backfire - why?
« on: June 18, 2016, 03:48:08 AM »
So just back from a first 5 mile jaunt to test the newly upgraded Enduralast 450W charging system.

Seems good, charging at 13.7-14.4V at low revs, Alternator can be heard whirring away and the Bikes former banging and popping on the overrun seems to have gone away?

I couldn't believe it at first, but took it up and down to hi revs to see if I could make it exhibit the banging and popping on the overrun reported on an earier post - but nothing?

I've not touched the timing or mixture or even sealed the short pipes as previously suggested.

Just removed the Diode board and old Rotor and replaced?
Bike was obviously not charging previously.

Am I making this up - why would the new Battery and working charging system affect sparks and banging on the overrun?

Any ideas you expert types?
« Last Edit: June 18, 2016, 03:53:38 AM by jonathanrowley »

Offline Barry

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Re: New Charging system sorts out Backfire - why?
« Reply #1 on: June 18, 2016, 06:51:07 AM »
If the system wasn't charging before then the voltage seen by the ignition coils would have be quite low, probably a little under 12 volts.

With the new charging system the ignition coil will be seeing up to 25 % more voltage. As spark energy increases with the square of the current or applied voltage then the improvement in spark energy is in excess of 50%.  That could well be enough to ignite the weaker overrun mixture and eliminate the popping.
« Last Edit: June 18, 2016, 06:54:40 AM by bhodgson »
Barry Cheshire, England 79 R45

jonathanrowley

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Re: New Charging system sorts out Backfire - why?
« Reply #2 on: June 18, 2016, 11:58:49 AM »
Barry - thanks, I couldn't work out an answer to this, but yes makes sense when you lay it out like that..

It definitely was not charging, never has I think - meaning the Batteries - 2 so far - now 3 with the new one, just discharged and died over time - amazing, as I've been running the Bike for 2 years with re-charges and an oxford maximiser to keep it moving.

50% more Ziggies is certainly making a big difference.
The bike has pretty much been re-built now electrically - new Coil, ICU, Bean Can, Charging system and Battery. Feels like a different machine.

Offline montmil

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Re: New Charging system sorts out Backfire - why?
« Reply #3 on: June 18, 2016, 12:53:28 PM »
Here in Texas, we explain the how and why of such miracles by saying, Don't look a gift horse in the mouth.

Ride Happy!
Monte Miller
Denton, TEXAS
1978 BMW R100S
1981 BMW R65
1983 BMW R65
1995 Triumph Trophy
1986 VW Cabriolet

Offline nhmaf

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Re: New Charging system sorts out Backfire - why?
« Reply #4 on: June 18, 2016, 09:02:28 PM »
Yup, I'd say Barry's theory is likely the explanation - you weren't getting consistent, reliable ignition before, so some cycles were pumping some combustible fuel mixture into the exhaust system on the overrun
Airhead #12178 ? BMWMOA #123173 ?BMWRA #33525 ?GSBMWR #563 ?1982 BMW R65LS ?1978 BMW R100/7 1998 Kawasaki Concours

jonathanrowley

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Re: New Charging system sorts out Backfire - why?
« Reply #5 on: June 19, 2016, 08:00:28 AM »
Makes total sense - thanks guys, happy with the outcome and a side affect of the charging upgrade it's always popped since built 2 years ago. So a result.