Starter motor stuck on after bike rebuild R80RT 1983

Discussion in 'Airheads' started by MikeO, Jun 6, 2012.

  1. MikeO

    MikeO Part-time wage slave...

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    Good evening all,

    I've been rebuilding my 1983 R80RT this week. The bike has been off the road since March when I removed all the bodywork and left it with my friendly neighbourhood paint sprayer. I picked the bodywork up on Monday and have been rebuilding it yesterday and today.

    Whilst the bike has been in the garage I have intermittently had it connected to a battery tender. A couple of weeks ago I fitted a set of HiCap battery leads, a stainless battery tray and other bits of bling. At that stage I reconnected the battery (although there was no ignition switch fitted so nothing worked). I cannot remember whether I put it back on the tender, to be honest - I think probably not.

    I got as far as reconnecting all the electrics at the front end of the bike today and decided to check that everything was working. I turned the key - nothing. No warning lights and the clock wasn't working.

    I checked the connections on the ignition switch, but they are exactly as they were before the strip down.

    Starting at the basics, I put the meter across the battery terminals. Nothing - not even a glimmer. I immediately checked the meter on the Adv and got a fully charged reading.

    The battery is a wet cell - I have been so used to gel batteries that I am ashamed to say I hadn't looked at the levels, all of which were below the minimum line. Poo - new battery time... :bluduh

    A neighbour came over and offered a set of jump cables. I parked the Adv alongside and connected the batteries up. As soon as I connected the Earth (second) cable, the RT's starter motor fired. I disconnected and rechecked that the ignition was off, then reconnected with the same result. I noticed that the clock started running - the starter continued to run no matter what I did to the kill switch, starter button or ignition switch. I switched the lights on, but they stayed off (I think they are disabled when the starter operates anyway, but I may have made that up).

    It was getting late, so I took the battery out and left the bike for the evening.

    Now, let's go back to fitting the HiCap leads. These come as a kit from Motorworks and will improve your starting, make the day brighter and generally improve your life. They are meant to be a straight swap, but they are not (and this may be significant). The earth lead is a straight swap, but the OEM positive lead splits into two, one cable connecting directly to the starter, and a smaller cable running to the starter relay. I called Motorworks about this when I was fitting it and they advised splitting the original positive cable and running the original wire to the starter relay, and running the new one to the starter. I did this with no particular drama.

    I do remember that fitting everything neatly under the starter cover on top of the engine was a bit of a struggle and wonder if I've touched something against the inside of the cover or something.

    Any ideas on what might be causing this please??

    Mike :ear
    #1
  2. Wirespokes

    Wirespokes Beemerholics Anonymous

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    Either the starter relay is activated when it shouldn't be, or it's fried (always on). Check to see it's properly connected, then try swapping in a different relay.
    #2
  3. MikeO

    MikeO Part-time wage slave...

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    Thanks for the input Wirespokes.:thumb

    New battery fitted today - exactly the same symptoms. :bluduh

    I disconnected, then took the starter motor cover off and unbolted the positive cable. I then reconnected the battery and MOST things worked fime.

    What doesn't work:

    Rear light (brake light does - maybe a bulb - will check).
    Headlight, on neither dip nor main beam (although it does work when you hit the 'Flash' switch). Is there an interlock that stops the headlight coming on if the engine isn't running?
    The side light only works in the sidelight and 'park' position - this may be normal??

    Back to the main event - the starter. I removed the motor (along with the front cover, diode board etc) and put it on the bench...

    [​IMG]

    The way it should work is that when power is applied to contact A (male spade connector) then the solenoid engages, allowing the main cable power, connected to contact B, to fire the motor.

    I put the motor in the vice and earthed the casing, then applied the positive terminal to contact B - no effect (as it should be). When I bridged A&B with the positive cable, the starter fired. So all seems well there.

    The cog on the motor is in the resting position - so nothing jammed there...

    [​IMG]

    I got my multi-meter put and checked the wire going to contact A. With the ignition off it was dead. With the ignition ON, it registered about 2 volts :confused With the ignition ON and the starter pressed it measured 16v (exactly as it should).

    So, the 2 volts shows all is not quite right in that circuit. But the problem is that the starter fires whether the ignition is on or off. It also fires when the starter relay is removed.

    Darren at Motorworks reckons it'll be something quite easy to find - we're talking again tomorrow.

    Incidentally, the motor is a Bosch one, which the Clymer manual suggests changing for a Valeo one. Darren's view is that the Valeo motor will spin the engine quicker, but it's notoriously unreliable. He reckons the best course is to use a Bosch motor coupled with a set of HiCap leads - it should give me the best of both worlds.

    Any more ideas?

    Mike :ear
    #3
  4. Wirespokes

    Wirespokes Beemerholics Anonymous

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    Mike - One of your pics didn't come through, and I'm guessing that's where the cantact A is pointed out. So I don't know where that is.

    So the starter motor checked out ok.

    Move on! Don't worry about replacing it - it works!

    Did you pull the starter relay? It's in the socket on the left side of the frame by the steering head. If it's got a horn relay there will be two little black relays side by side.

    You shouldn't have 16V anywhere in the system except maybe the diode board. Did you mean 12V? Maybe 12.6?

    With the relay removed, the starter shouldn't operate at all unless there's something wrong internally - which you've determined to not be the case.
    #4
  5. gerrynj

    gerrynj Been here awhile

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    If the started checks out - and it looks like it does based on your tests then I would suspect the starter relay. I just helper out a friend who had the exact opposite problem. Nothing would happen when you hit the started button.
    We checked everything - then we removed the starter relay and sure enough it was dirty inside. We cleaned it up - lubed it - and everything works now.

    You may have the same issue - try another starter relay - or open up the one
    you have. It could also be your starter button that is ON all the time - have you
    checked that the button does in fact switched on and off when pressed?

    As someone else said - you should NOT have 16 volts anywhere in the system
    Gerry
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  6. rambozo

    rambozo Been here awhile

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    don't know if this is of any use, but when i built my r80 i mistakenly put the wire that runs from the starter relay to the headlight relay(the one that also runs to the starter solenoid, terminal 30 on the starter relay) to the earth point on the fuse board

    this made my starter work all by itself, and gave light problems similar to yours

    there's a resistor in the headlight relay that switches the headlight off(or something like that) when the starter is activated

    maybe worth checking that wire for damage
    #6
  7. MikeO

    MikeO Part-time wage slave...

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    Thanks everyone for the input. The 16v is the across the terminals reading on my (new) battery - not under load. In my experience 14-15v is normal, until you press the starter, so I don't think the 16v is an issue.

    Right - today's analysis.

    The starter fires with just the positive lead from the battery connected to the solenoid - no other inputs. This is at odds with the test on the bench yesterday. There is no resistance between B and A, or B and C, but there is (as there should be) between A and C.

    [​IMG]

    We have discounted anything to do with the starter relay, as this problem occurs with no other input than that described. It has us stumped. I have checked that the contact stud (B) does not rotate when tightening down, but it's fine. It kind of defies logic... :bluduh

    Our best guess is that it is an intermittent fault within the solenoid.

    Darren at Motorworks has been a great help and is sending me a used solenoid on a sale or return basis. I have removed the starter (again) and taken the solenoid off in preparation for the replacement's arrival.

    Other matters - the tail light was fixed by replacing the bulb (the one win of the day:D). The headlight dipped and main beam do not work. With sidelight selected, I get the front & rear sidelight. Switching to headlight extinguishes the sidelights (front and rear). This is true whether on dipped or main beam. The headlamp flasher switch still operates the main beam correctly.

    Rambozo, I'll check the run of the wire you describe. :thumb

    I've had enough for today, I think. I will be able to fit the new solenoid to the starter later next week, but won't be able to refit the starter until the weekend in all likelihood - so please keep coming up with suggestions - it's really appreciated...

    Cheers,

    Mike :brow
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  8. Wirespokes

    Wirespokes Beemerholics Anonymous

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    There's something wrong with your solenoid!

    You should not have continuity between A and B!

    If the starter operates attaching a ground to the starter case, and a positive lead to B - you definitely have a problem with the solenoid.

    What are side lights? Are you talking about the turn signals?
    #8
  9. MikeO

    MikeO Part-time wage slave...

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    High Wirespokes,:wave

    There is no continuity between A and B.

    The starter operates when attaching a positive lead to B - but only when fitted to the bike, not on the bench...:baldy

    [​IMG]

    Mike
    #9
  10. Wirespokes

    Wirespokes Beemerholics Anonymous

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    Nice looking bike Mike!

    Side light - never heard it called that. Parking light I believe it's called over here.

    That is odd why the starter won't operate normally on the bench. I can't think with that one...
    #10
  11. MikeO

    MikeO Part-time wage slave...

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    Hi Wirespokes - that's BEFORE the respray... :D

    (The paintwork looks a lot better in that pic than it did up close).

    To be clear, the starter works correctly on the bench, but not on the bike...

    Mike :thumb
    #11
  12. Wirespokes

    Wirespokes Beemerholics Anonymous

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    I'm really batting a 100 on this one! :rofl
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  13. gvganser

    gvganser Adventurer

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    Make sure that the positive connected to solenoid isn't touching any other parts. I made that error last year when installing a new starter. When I tightened down the positive it rested on a fin between the solenoid and cable to starter.
    #13
  14. MikeO

    MikeO Part-time wage slave...

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    Thanks gvanser,

    I had a careful check around and couldn't see anywhere the cable could touch (it's insulated right up to the eye), but as a precaution I'm going to re-route it when refitting the motor (after fitting the spare solenoid).

    Cheers,

    Mike :thumb
    #14
  15. MikeO

    MikeO Part-time wage slave...

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    :lol3
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  16. R100LT

    R100LT Chasing 11

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    Hey Mike

    In regards to your headlights it sounds similar to what I experienced with my RT . I had just changed over to HID lights amongst other things ... and when I tested with the tank off it worked fine ... put the tank back on and I couldn't get high or low beam ... just the flasher ... take the tank off to check ... it all worked fine.

    Drove me mad for a couple of days ... checked everything ... from my wiring of the new HID and relays etc ... By chance I lent on the electrical connectors ( left hand side of frame, past the relays ) and it all worked fine. Basically I think they must have worked lose whilst removing and replacing the tank a few times.

    Solution was just to simply to tape them down a bit tighter to make a better connection.
    #16
  17. MikeO

    MikeO Part-time wage slave...

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    :clap:clap:clap

    The new (used) solenoid arrived from Motorworks today...


    It wasn't the solenoid that was the problem.

    More and more these last few days I have been coming to the conclusion that this was something REALLY simple. Sure enough, when refitting the starter (with the battery connected) I brushed the INSULATED end part of the power lead against the starter case and got a spark.

    There was a fine cut in the insulation that tightening down opened up and created the short. A bit of red heatshrink later and the starter works as advertised, as does the headlamp.

    Thanks very much everyone for your words of advice - it is really appreciated. :thumb

    Let the rebuild continue!

    Mike :brow
    #17
  18. Wirespokes

    Wirespokes Beemerholics Anonymous

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    Well done getting that one sorted out! Chalk one more up to just taking a good close look!
    #18