I keep blowing starter fuses

[RetiredGuzzi]

Hopefully someone can help me with insight on blowing starter fuses.

History: 2007 Breva 1100. Ridden weekly for years with never a problem. Recently the bike sat for 3 months, started the bike, was running fine for @a minute and I had to turn it off to use the keys to lock a bag. Would not start back up.

Trouble: Tried to jump it off but it would not start. Thought it might be a weak battery, so I charged it, put it back in but nothing. Went through the fuses and found the STR 15A fuse blown. Replaced the fuse, the bike started right up. The next time I went to ride, nothing. Checked the fuse again and it was blown. Replaced it, blown, replaced it, blown.

Would anyone have a clue why it keeps blowing this fuse? Thanks in advance for any insight.

[Thunderbutt]

Sounds like your bike is suffering from the Startus Interruptus Syndrome.  Plenty of info regarding that here.  Check ALL your main battery connections for corrosion at frame and even starter solenoid.  Also, dont hesitate to replace the starter relay. 
After I checked all terminals and connections I replaced the relay and ran a new heavier gauge wire from the relay to the starter solenoid.
If that doesnt cure it check inside the ignition switch, some have found problems there.  Hope this helps

[rodekyll]

Hello, and welcome!  I can't help you (I'm an antique Convert kind of guy -- don't understand these moderner ones), but we have some rather sharp people who will know.  You might save some time by searching 'starter fuse' and 'startus interruptus'.  Use the search function on the top right part of the page.  I does something with Google and searches wildguzzi.

[Wayne Orwig]

Trouble: Tried to jump it off but it would not start. Thought it might be a weak battery, so I charged it, put it back in but nothing. Went through the fuses and found the STR 15A fuse blown. Replaced the fuse, the bike started right up. The next time I went to ride, nothing. Checked the fuse again and it was blown. Replaced it, blown, replaced it, blown.

Would anyone have a clue why it keeps blowing this fuse? Thanks in advance for any insight.

Not too uncommon.

The long story is, the starter solenoid pulls well over 30 amps when you press the button. NORMALLY, once the solenoid pulls in, there is a bypass that drops the current requirement well down, and the 15 amp does not pull.
So, you likely are not getting the solenoid pulled in fast enough.

One option, would be to use a 20 amp fuse. Probably not the best answer even if it helps.
Another option, would be to pull the starter and clean the solenoid. Make sure it is free to quickly pull and hit the bypass contact.
A third, common option/problem, we often call startus interuptus. The wiring that feeds the solenoid is quite long and goes through a number of circuits. It often does not provide enough power to pull the solenoid. So you get a non-start. Maybe enough current to pop the fuse, but just not enough to pull the solenoid.  If you search this site for startus interuptus, you should find a number of fixes for it. MPH used to make a plug and play fix, and I think it is still available.

[RetiredGuzzi]

Thank you all for this information. I'll be spending the day tomorrow trying the fixes you've suggested. Thanks

[Kiwi_Roy]

The starter solenoid would like to pull 45 Amps for a split second, there's just too much resistance in the wiring and switches for it to do that. Solenoid engagement becomes sluggish as resistance (electrical and mechanical) builds up with age to a point where it's pulling enough current to blow the fuse but not enough to get the plunger moving.
After the Startus Interuptus fix the starter will engage and start turning in half the time.

Don't over lubricate the solenoid plunger,  the oil may go gummy causing it to stick, some guys put them together dry but I usually use just a single drop of 3in1

Sometimes cleaning the ignition switch is all it takes, the grease get's hard with age, fresh Vaseline will perk it right up but the fix is a better long term solution.

Using a 20 Amp fuse might act as a short term fix.

Always use grease on the battery leads, it prevents the lead from oxidizing (lead Oxide is an insulator)

[RetiredGuzzi]

Thank you all for all the help. I cleaned off all the connections and since I have not had a bit of trouble. I think she was just upset with me for not riding her more often, so I stroked her tank, looked into her headlight, and promised to read her more often. Thanks again for everyone's help.

[Kiwi_Roy]

It will likely occur again one day if she catches you looking at other bikes. The fix is very easy to do on a Breva