961 - Heavy Misfire - the full kangaroo

iwilson · Apr 19, 2019

My 2c, do you see anything else occurring at the same time? i.e. instruments behaving strangely? I know you've looked at the electrics but it might be worthwhile having another look with the engine running. Remove the fuse cover and wriggle all the relays and fuses as well as all the wires feeding into the fuse box and see if the engine stumbles. It's possible that a fuse/relay/fuse holder is not sitting snugly or has a hair line crack. I mention this because I've suffered from all of the above! The amount of vibration and its effect on the electrical system cannot be under estimated!

Given the starter motor is also causing problems I'd be making 100% certain the main fuse (inside a little cover next to the battery) was firmly seated. As the starter motor draws a lot of current a poor connection would allow the electrics to operate (poorly) but the starter motor would struggle to operate - this fits with your symptoms.

Here's a vid showing an example. In this case a hair line crack in a fuse - the fuse looked ok and metered out ok, but with the engine running it was like a little on/off switch!

Jump to the 30 sec mark to see the problem.

TerryW · Apr 20, 2019

Hi Guys,
I have been all over wiring like a cheap suit. But, I’ll go over it again literally using a magnifying glass.

I shortened the plug leads yesterday and that seemed to make a difference. The violent kangaroo was asleep. However, I only got a few hundred yards before a softer misfire stopped me dead. This seems fuel related as the engine just whirred to a halt. I cant get back on the case for a day or Two.
Instruments: on the led screen in the speedo , when I switch on it initially says low voltage. This almost immediately disappears and the battery reads 12.7v. The engine spins easily on the starter. When cranking the voltage drops but she starts as usual and runs. When warm she idles fine.
I am going to do a fuel flow check and see if the pump is delivering after I check the wiring again.

Thanks for all the advice so far.

Terry

Ps I didn't mean the starter operates on its own. I was clumsily saying that after a stoppage sometimes pressing the starter button has no effect and its function is restored by turning the ignition key switch off then on. Might be a clue to an intermittently dodgy relay. I suspect that I am wrestling with a couple of simultaneous faults.

MxMartin · Apr 20, 2019

With that starter switch giving you occasional probs I'd take a good look at that switch housing and give the kill switch a thorough check over, could it be making/breaking intermittently when engine is running?

Raphi · Apr 21, 2019

Fast Eddie said:
Texas to Niagra falls Rich? That’s a good ride!!

I think we should point out here that whilst anyone with an older 961 may have the knock off coil issue, the newer bikes use the genuine Bosch items.

Well, the very early bikes had Bosch coils as well. Mine is a 2012 and when I wanted to swap the coil I noticed it already was a genuine Bosch one...

Britfan60 · Apr 22, 2019

TerryW said:
Hi Guys,
I have been all over wiring like a cheap suit. But, I’ll go over it again literally using a magnifying glass.

I shortened the plug leads yesterday and that seemed to make a difference. The violent kangaroo was asleep. However, I only got a few hundred yards before a softer misfire stopped me dead. This seems fuel related as the engine just whirred to a halt. I cant get back on the case for a day or Two.
Instruments: on the led screen in the speedo , when I switch on it initially says low voltage. This almost immediately disappears and the battery reads 12.7v. The engine spins easily on the starter. When cranking the voltage drops but she starts as usual and runs. When warm she idles fine.
I am going to do a fuel flow check and see if the pump is delivering after I check the wiring again.

Thanks for all the advice so far.

Terry

Ps I didn't mean the starter operates on its own. I was clumsily saying that after a stoppage sometimes pressing the starter button has no effect and its function is restored by turning the ignition key switch off then on. Might be a clue to an intermittently dodgy relay. I suspect that I am wrestling with a couple of simultaneous faults.

My bike never gave me a "low voltage" reading until recently, and like yours, it only says it for a second then goes to 12 and change. This is not long after the battery weakened a little and my digital display started freaking out again. Always does that if I forget to plug in. I'm guessing its almost time for a new battery again even though this one is only about 2 years old. Stock lead acid Yuasa. No problems firing right up though and after being back on the tender, the display is normal again.

Hope you're sorted soon. Odd about running a little better after trimming the plug boot. Wonder if you have a bad wire.

TerryW · Apr 24, 2019

A bit of an update for anyone following my sorry tale. I am feeling a bit knackered at the moment as I just pushed the bike home again. I tested the fuel pump pressure and got 4 Bar (good pump). I had made good the spark plug leads to I was eager to see if I had any improvement. So, I went for a run up and down the road for 30 minutes. Got lulled into a false sense of security and went for a whole run around block. It conked out of course. Plenty of battery; no start. Pushed her home and found no spark at all. Fuse blown in the fuse panel. I replaced the fuse and got power on the coil.
The coil is a Bosch 0221503035. The fuse is rated at 10A. I can't see any probs with the wiring. So, I'll start to check that:
a) this is the right coil for the application.
b) 10A is the right fuse size.

Can anyone chip in before I splash out on a new coil and leads please? I would hate to fit a new coil and find that it needs a 12A fuse.

PS I had tested the coil and it draws a whopping 10mm spark. This doesn't mean it is faultless but it looked good when I tested it.

Terry

BritTwit · Apr 24, 2019

TerryW said:
A bit of an update for anyone following my sorry tale. I am feeling a bit knackered at the moment as I just pushed the bike home again. I tested the fuel pump pressure and got 4 Bar (good pump). I had made good the spark plug leads to I was eager to see if I had any improvement. So, I went for a run up and down the road for 30 minutes. Got lulled into a false sense of security and went for a whole run around block. It conked out of course. Plenty of battery; no start. Pushed her home and found no spark at all. Fuse blown in the fuse panel. I replaced the fuse and got power on the coil.
The coil is a Bosch 0221503035. The fuse is rated at 10A. I can't see any probs with the wiring. So, I'll start to check that:
a) this is the right coil for the application.
b) 10A is the right fuse size.

Can anyone chip in before I splash out on a new coil and leads please? I would hate to fit a new coil and find that it needs a 12A fuse.

PS I had tested the coil and it draws a whopping 10mm spark. This doesn't mean it is faultless but it looked good when I tested it.

Terry

10A fuse for coil and ignition is what the manual specifies.

Clive · Apr 25, 2019

I know you mentioned you checked relays but I had an issue a while back where the bike would run then cut then run. It cut on the way back to the factory - instruments went crazy then completely cut. Roll started it down a hill - ran rough then cut again. Got it back to the factory and it was an 'ECU relay' issue. No recurrence since. Recently had a relay issue with high/low beam. Was told that the wiring looms come with the relays attached...

TerryW · Apr 25, 2019

Hi,

I can’t see inside the relays so my checking was just pull relay out, inspect connectors and push back in. No signs of overheating. Looked pristine.

I have since found a poor quality wiring diagram and can see that current is drawn through the fuse that blows by 5 devices. Only 3 of them are recognizable from the diagram (in the service manual). It is a very poor reproduction. I have asked Rob in Norton to supply a better reproduction and offer advice.

Later today, I will electrically test the ignition relay and try and hunt down and test the mysterious diode and examine more wiring. This morning I have a 100 mile drive to clean a boat’s bilge.

Thanks for the advice.

Terry

Clive · Apr 25, 2019

TerryW said:
Hi,

I can’t see inside the relays so my checking was just pull relay out, inspect connectors and push back in.

Terry

My relay failure was on a bike less than a year old. A year on I could hear the headlamp relay clicking but the dip beam was not coming on intermittently.

TerryW · Apr 25, 2019

Rob Jameson in Norton was kind enough to email me a really good wiring diagram. This afternoon I'll be searching out any devices hanging off that fuse which is drawing an unexpected high current (coil pack, both injectors, ign relay coil, tilt sensor, tilt sensor diode, fuel pump relay).

TerryW · Apr 25, 2019

Couldn't find anything in least bit suspicious. I swapped relays around so that the main beam relay replaced first the ignition relay and then the fuel relay. Found the clutch switch wires loose in the headlamp. Made no difference. Ran around my village with a splutter out every 10-20 seconds.
I have given up any scientific approach and ordered a replacement genuine Bosch coil. We shall see if this cures the problem.
Terry

Fast Eddie · Apr 25, 2019

Terry, did you actually remove your fuel rail to check for the rust inside etc that you highlighted earlier?

I sincerely hope it’s the coil and all is well when you fit the new ‘un.

The cam and head temp sensors on the bike have also been suspected of being poor quality ‘knock offs’ in the past. The head sensor is also very easy to damage by all accounts. Probably worth buying new ones from a Bosch dealer. See post #10 in this thread: https://www.accessnorton.com/NortonCommando/new-to-961.22618/

If none of that works, I’d be tempted to park it somewhere and await the white van...

TerryW · Apr 25, 2019

Not removed the injectors yet. When the engine stops there is plenty of petrol on the plugs and the Exhaust so I went for a spark problem. Haven’t got to the white van moment yet but maybe I’ll build the first 900 triton . . . Wonder if there are any Triumph twins being broken up?

TonyA · Apr 25, 2019

Do you have the Norton Service Manual in PDF ? It has lots of good information . Someone can send it to you if you need it.

iwilson · Apr 25, 2019

TerryW said:
Couldn't find anything in least bit suspicious. I swapped relays around so that the main beam relay replaced first the ignition relay and then the fuel relay. Found the clutch switch wires loose in the headlamp. Made no difference. Ran around my village with a splutter out every 10-20 seconds.
I have given up any scientific approach and ordered a replacement genuine Bosch coil. We shall see if this cures the problem.
Terry

I'm still inclined to believe its not the coil or a sensor but more likely a loose or broken connector. Bike on a stand running with as much wiring exposed as possible and start wriggling until it cuts out. Here's a pic of a nasty fault that caused me all sorts of head scratching. The terminal had broken but was still held in place by the fuse terminal locking system (fuse box has to be disassembled to get at). Sometimes the engine would be fine then out of the blue would give problems. Without disassembling the fuse box you'd never have spotted it.

Fast Eddie · Apr 26, 2019

TerryW said:
Not removed the injectors yet. When the engine stops there is plenty of petrol on the plugs and the Exhaust so I went for a spark problem. Haven’t got to the white van moment yet but maybe I’ll build the first 900 triton . . . Wonder if there are any Triumph twins being broken up?

That’s been done.

However, you could be the first to build a 1200 Triton...!

Before I got to that stage, I’d think about ripping off all that troublesome shite and fitting a simpler ign and nice FCRs !!

Clive · Apr 26, 2019

Fast Eddie said:
I’d think about ripping off all that troublesome shite and fitting a simpler ign and nice FCRs !!

Never mind the yabber - why are yours still sitting on your mantlepiece gathering dust?

TerryW · Apr 26, 2019

iwilson said:
I'm still inclined to believe its not the coil or a sensor but more likely a loose or broken connector. Bike on a stand running with as much wiring exposed as possible and start wriggling until it cuts out. Here's a pic of a nasty fault that caused me all sorts of head scratching. The terminal had broken but was still held in place by the fuse terminal locking system (fuse box has to be disassembled to get at). Sometimes the engine would be fine then out of the blue would give problems. Without disassembling the fuse box you'd never have spotted it.

Wow. If the coil doesn’t do the trick I’ll get serious with the wiring again. I have already had a magnifying glass all over the fuse box but I was conscious of adding a fault by yanking it about.

MxMartin · Apr 26, 2019

I ran a new Kwaka GPz1100 down to Paris soon after purchase in the 80's but at around every 100km or so it blew the main fuse, I checked everything that I could by the roadside but with limited tooling I couldn't find anything obvious so I elected to buy a bag of 10A fuses and just replaced them each time they blew. On return home I eventually discovered that the tight fit of the tank over the wiring harness on top of the engine had caused the outer sheath to crack and the vibration of exposed wires on a cam cover bolt abraded the insulation on one of the wires and it randomly shorted to the engine. Once fixed the bike went on to give me 30k trouble free touring miles around Europe over the following seasons

961 - Heavy Misfire - the full kangaroo

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