Starter motor stuck on after bike rebuild

MikeO

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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... :mad:

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 :confused:
 
Mike, I have a K75S and had a similar problem a year or so ago, I thought the problem was with the starter motor (as Proff will confirm as I spent a lot of time on the blower with him :blast). The problem was caused by the battery getting low which caused the starter relay to stick in the open position so it was constantly trying to turn the engine over. I topped up the battery and put it on charge and before refitting I gave the starter relay a few vigorous taps in order to free the sticking contacts as they can get fused together. This freed them up and when I refitted the fully charged battery all was well. Hope that this is a similar problem for you as it is an easy fix. :thumb
 
Thanks Lord S.:thumb2

Not the solution, unfortunately. :mad:

New battery fitted today - exactly the same symptoms. 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 or 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...

i-J5Wsc9B-L.png


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...

i-LXPjnFP-L.jpg


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 :cool:
 
valeo starter

the valeo starters are ok if you rebuild them . replace the part that carries the magnets with one from a saxo ( more glue ) . there 's a few threads on here about it .
 
Just seen this post Mike.

When I rebuilt my mate's Old Nail R80/7 some years ago, I had exactly the same thing happen. It turned out to be a wrong connection, a silly little error.

I have vague recollections that it turned out to be something counter-intuitive, two wires should have been on one connection when (to me anyway) it looked as though they went on separate ones.

With the ignition on, as soon as the battery was connected the starter leapt into life. It took a bit of trial and error to track down the mistake (I disconnected the battery Neg lead, left the ignition switched-on, played with the connections and then just touched the Neg lead to see what happened).
 
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.

i-sVr2KKM-L.png


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... :mad:

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.

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 :cool:
 
If you check for continuity it should be open circuit between A B and C. When A is energized there should be continuity between terminals B and C.
 
RESOLVED!

: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. :thumb2

Let the rebuild continue!

Mike :cool:
 


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