1990 loud pop/backfire and lurches on acceleration

Discussion in 'Motor' started by TheMeanSupreme, Jan 20, 2018.

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  1. Jan 20, 2018 #1

    TheMeanSupreme

    TheMeanSupreme

    TheMeanSupreme

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    My 1990 Max has been giving me problems since mid-last summer. I'm a daily rider but learning to wrench as probs arise. Not the best situation but it's reality. So... I've had a charging problem since spring last year. Bought new battery and all was well for two weeks or so. Then the new battery died so I started putting it on trickle charger every time I wasn't on it. That'd give me about 15min of ride time before speedo light goes out, which I quickly learned was how the bike warned me that total electrical shutdown was imminent. Sometimes the tach needle would start just flying all over the place even tho the revs weren't. Then shutdown. Just put an aftermarket regulator/rectifier on it today and started it for the first time in 3 weeks. Sounded good to this noobs ears but could be down a cylinder, for all I know. Straight pipes on the bike so it's LOUD. Neighbors hate me. Also have gas in the oil periodically. So as you can see, this is a total mess and I'm flying in the dark, here. Anybody brave enough to offer to try and sort this clusterf**k out will have legendary status in my small life.
     
  2. Jan 20, 2018 #2

    1FK00

    1FK00

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    Had the exact same problem on my '85, tach misbehavior and all. The remedy was to put a ground from the batt negative directly to the frame. Also make sure the battery isn't running out of electrolyte.
     
  3. Jan 20, 2018 #3

    ga_max

    ga_max

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    The other issue could be that the RR is not putting out enough voltage to keep the bike running. Put a multimeter between the pos and neg terminals and see what the voltage reads at idle and at 3K rpm. Mine puts out 14.4 volts at idle.
     
  4. Jan 21, 2018 #4

    Eugene Brad

    Eugene Brad

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    When you replace the R/R did you take the plug from the stator to R/R out and replace with solder connection or posi-lock? My charging issue was fixed by getting shut of that plug. Check voltage from stator at the plug to ensure good voltage there.

    Sent from my SM-G360V using Tapatalk
     
  5. Jan 22, 2018 #5

    MaxMidnight

    MaxMidnight

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    No point in guessing what the problem might be, you need to do diagnostic checks in a logical manner.
    This will save you time and money and increase the chance of getting a right first time fix.


    Three causes for fuel in the oil
    i) Float needle not shutting off/ float level too high/ float damaged. Check plugs to check for a richer mixture on one (or more) cylinders.
    ii) Lots of short runs with the choke on - get the motor up to operating temperature which will allow the fuel to boil off.
    iii) Choke(s) not shutting off. Check the linkages are free and the plungers fully return.
     
  6. Jan 22, 2018 #6

    TheMeanSupreme

    TheMeanSupreme

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    Thx for all the info and suggestions, fellas. Gonna start working thru them right now. I'm sure I'll be asking more questions as I go but before I even start, I have one more about the regulator. It's a 6 pin job -power, negative, ignition switch/sensor, and the last 3 go to the coil. My question is about the ignition switch/sensor. The stock unit only had 4 wires total - power and the three coil wires since it was grounded thru the unit itself. So I know why this new unit has the ground wire, but what about the ignition switch wire? Do I need to run z line to the ignition, sort of like you'd run a wire to the "acc" when installing a car stereo so that the unit turns on when you turn the key? Thanks in advance for any and all suggestions and corrections as I finale my way they this, everybody. Ok, I'm diving in....
     
  7. Jan 22, 2018 #7

    TheMeanSupreme

    TheMeanSupreme

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    I think saying "coil" when I mean "stator". The diagram that I have that identifies what each pin does on the regulator calls those 3 pins "power coil". Wondering why that is... It's not a tall order to confuse a beginner like myself, which is plainly evident, no doubt.
     
  8. Jan 25, 2018 #8

    MaxMidnight

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    I don't think you connect the ignition switch wire...see here, last picture.
     
  9. Jan 27, 2018 #9

    TheMeanSupreme

    TheMeanSupreme

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    Thx, Steve L. I think I might be s.o.l, tho. Gonna re-install the regulator, this time a little better than half-assed, and hope for the best, but when I fired up the bike after installing it the first time, the battery was reading 11.42 volts and I didn't see it rising. That points at the station as the culprit, right?
    There's one thing I didn't put in the original post, because I was pretty sure my problem started before this, but now I need someone to blame so here's what happened:
    Coming home late at night last spring and saw a Harley broke down (no surprise there, right?lol) on the side of my off ramp. Guys air ride went out. Told him to baby it the ⅛ mile to my place as I have tools & a garage. He ended up camping on my couch (wife not happy, let me tell ya) and we got his air ride handled in the morning. When he tried to start his bike, tho...nothing. Dead battery. Tried to I jump it off my bike, but no joy. I went across the road to ask my neighbor for a jump and when I came back, this guy has the jumper cables hooked to my solenoid and is trying to crank his bike again. Smoke is coming from below my battery at this point. Hot wire to the stock regulator is fried somehow. This is why I started there trying to fix the charging issue. Any ideas? Thx again, man.
     

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