Probably a common Monster issue but...

[Skeldy]

Hi All

My 2003 Monster 620ie has an intermittent electrical issue that I’ve read quite a lot about online, but no successful fixes. Hoping someone understands the problem:

Once every while, without any obvious pattern, the electrical system goes completely dead when attempting to switch on. Like there’s no battery connected - not even yellow immobiliser light flashes. No dash lights or dial spins when I insert the key. Another day, it will be fine.

Stuff I’ve tried:
- new battery
- replaced rec/reg with new MOSFET unit
- fiddled with and checked every visible connection I can see

No luck. I know the battery and new reg work because they fired up the first time then I switched off and the system went completely dead again.

Welcome q y advice and experience of this.


Cheers

[slob]

main relay. on the left hand side of the battery
http://www.ukmonster.co.uk/monster/showpost.php?p=554424&postcount=3

[Dukedesmo]

Agreed, sounds like main relay. I had this on my 916 - intermittent but total electrical failure, usually when first switching on the ignition.

On my Monster (and 916) it is a yellow relay, not your standard changeover relay as it has two NO contacts rather than a NO/NC but they are (probably) available from motor factors and online as well as Ducati though not as common as the normal changeover relay.

Best buy two so you have a spare...

[slob]

Skeldy’s profile says 620ie, if that’s correct they’re next to the battery under the tank and interchangeable (main and efi) with each other as a basic test

[Skeldy]

Thanks. New relays on order ��

[Skeldy]

Hi guys,

Two new relays installed. Master fuse checked. Battery fully charged.
Still as dead as a dodo. Not even the yellow immob light on.

Any other thoughts or theories please?

Cheers
Rob

[Luddite]

That's frustrating.

My old M900 used to completely cut out intermittently and it turned out to be chafing wires where they passed around the steering stem. When the bars were straight, the wires made contact and it ran fine but, as soon as you turned them more than about 10°, everything went dead. There was no obvious external evidence of this unfortunately but you could just feel the break through the insulation.

I don't think this is a unique problem so it might be worth checking this area on yours.

[Darren69]

No its fairly common fault on bikes of that era. I noticed tthe loom on my bike has been installed the other way around by the previous owner, presumably to prevent this.

[Skeldy]

Thanks guys. Found the culprit. Melted 30A fuse. ����
I had checked the main fuse under the tank but not this one. My first monster ... learned a lot in the past week. Appreciate your help
����

[Dukedesmo]

You might want to investigate as to how the fuse melted as there shouldn't really be that much current draw anywhere?

The fuel pump fuse on my 916 melted, along with the holder and some of the insulation on the cable - probably due to the pump working extra hard due to the filter being partly blocked?

It was still working though despite being a ball of squidgy plastic... :scratch:

[Darren69]

Melted 30amp fuse? That's not good, could be fuel pump as Duke says or otherwise a big short out somewhere (starter circuit maybe? Relay, motor). Look for melted wires somewhere.

[Mark9]

Melted 30A fuse could be because it’s loose, mine went, when I pulled it out it just slipped out with virtually no physical resistance, it wasn’t being gripped properly by the connectors that it slides into, it was one of those really cheap ones made of very thin metal, I swapped it for one from Halfords made of a thicker gauge metal and this one had a nice sliding fit into the connectors, no further problems.