Blowing fuse on start-up

My '09 G12 blew the 15 (amp? volt?) fuse on start-up this morning. This is the second time and I am armed and ready with my can of DeOxit. What should I be disassembling and cleaning to prevent this issue? Is this related to Startus Interruptus? DW

Could be. Check/clean the battery lugs and terminals. Check/clean the earth strap connections on the starter.

And replace the fuse with a 20A. It'll still blow if you get a short but it will be less likely to do do with the instantaneous current draw from the circuit if resistances are just a bit high.

Pete

Thanks Pete, I did the battery lugs and ground strap. I have a 20A ready for the next time it blows.

Pete means put the 20A in now - so there is not a next time - or at least the odds are more in your favour...

+1 on 20A fuse

I replaced mine with 20A fuse after my GRiSO popped a dozen of 15A.

It will still do the "click-and-nothing" when I press the start button from time to time but the extra 5A save the fuse from popping.

When I had this problem, I finally solved it by cleaning and rebending the "tangs" that connect the "brush carrier" to the body of the starter motor. Just FYI . I did try all the other fixes first, but this was the one that solved it for me.

Thanks to all for your responses.

Phang, I thought your bike was perfect in every way. Now I hear that it has been "modded"

These tangs, are they on the inside or outside of the starter?

DW

guzziownr wrote:

Thanks to all for your responses.  

Phang, I thought your bike was perfect in every way.  Now I hear that it has been "modded"

These tangs, are they on the inside or outside of the starter?

DW

It was a dilemma.

In the beginning, I have tried cleaning and greasing the usual suspects to lower the resistance of starting circuit, that only last for a while. The more common and proper solution is the starter relay bypass mod.

It is against what I have learnt to put a 20A fuse in a 15A fuse holder, much like a taboo but I did it anyway.

So the 20A fuse solved the fuse popping issue, left with the random and occasionally "startus interruptus"

When that happened, the second try usually starts the engine. Rarely I have to jab the start button for more than three times. In fact, if you press and hold the start button rather than a short jab, it will bypass the automatic starting mode and goes into manual mode, taking out ECU intervention and allow you to crank it the old fashion way (green path in the diagram).

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I have to admit I quite like it. At times, she will throws tantrum to remind me that she is an Italian bella but never enough to strand me at the road side.

Until things get worse, I will keep it this way and shelve the idea of starter relay mod

The "tangs" are on the inside of the starter. I'm afraid you need to remove the starter and then remove the two long (m8?) bolts that hold the end cap on. Once disassembled you can see that the plate that holds the electric motor brushes connect to the body of the starter (and thence to earth) via a couple of bent bits of metel (the tangs). these only connect (electrically) to the body of the starter by "interference" (touch). On another starter motor (Honda CX650T), a recognised fix is to permanently wire the brush plate to the starter body to ensure a good electrical connection!

Hopefully on of the other fixes will work for you, but if all else fails try this one. The starter fuse blowing is a well known GRiSO problem discussed here and in other forums

What a great thread! Thanks to Phang for the information on the circuit and to "crisis" for the tang tip. Starter disassembly holds no terrors for me. I was a Guzzi Beta Tester for the early days of the Valeo

Just to clarify then, my starter is a Bosch (09 UK GRiSO). I was a bit embarrassing to discover that the problem was with a German starter motor after I had been so rude about Italian electrics!

I imagine the Valeo internals are very similar? Seems to me like all starter motors are very similar?

Midlifecrisis wrote:

I imagine the Valeo internals are very similar? Seems to me like all starter motors are very similar?

The Valeo was a French design made in China.  The magnets were attached with used chewing gum and were failure prone.  The later ones were better.

Where are these tangs exactly?

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See picture in this link. Tang is at 4-30 position. Its just a bent (forked in this case) piece of metal, but it forms the electrical contact to the starter body. I cleaned mine (there are two on the Bosch) with a piece of wet n dry and bent it out a little to get a better contact

Circled in red.  Hmmmmm...
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15A went poof, 20A in place now. I had a nice ride through the hills to West Point Military Academy. They have their own golf course and ski slope!

I guess that the bent tang/starter motor/electrical contact is cheap and easy and seems to be common industry practice, but I also understand why some owners (especially in the "classic" arena where bikes are used less frequently) prefer to run a nice thick wire between the brush plate and the starter body. Although I've not done this on my GRiSO, it works a treat on my CX650T!