Fried plug, intact fuses, reletively new R/R from Honda... wtf? Help please?

I've got a 1990 VFR750F and she's been ridden every day for the last year (My main ride) with no major issues, until yesterday morning. I did extensive research on the Interceptor before I bought her and knew going into it that there was a history of R/R issues and my bike had a new R/R (SH701-12 Honda replacement?) installed shortly before I purchased it for this reason. I know because the old fried one was left under the seat.. there is a ton of great info out there on R/R issues however my experience has been a little different from the ones I've been reading about. Basically: I choked the bike as usual for a cold start, put in the key and turned it until my dash lit up, then switched to start; nothing out of the ordinary. Then I hit the ignition and the engine turned for a split second then everything died, immediately. No lights, no engine turning, nothing. I immediately checked all of the fuses and they're all intact, however the plug from the wiring harness that connects to the main fuse hub (Bikebandit.com has this part listed as “SW, STARTER MAGNETIC” but doesn’t go into specific plugs on the harness) has a hole melted through it, right down to the prongs. Again, no fuses blown. Any idea’s as to what could have caused this? It’s been 1 day and I’m having riding withdrawals!! I’ve included a pic below. Any help would be incredibly appreciated!

 

It was probably a dirty and/or oxidized connection. Whenever an electrical connection gets compromised, it becomes a "load", rather than an electrical pass-through. When it is a high current connection, it gets hot very rapidly, and the heat makes it become even more of an electrical load, which makes it get even hotter, which makes become even more of an electrical load, etc., etc.

It is always a good idea, depending on the environment where you live, to occasionally disassemble the high current connections and clean them up a bit with a very fine wire brush. All you want to do is knock off the surface junk, not score the metal. That would also include the negative lead from the battery to the chassis connection, FWIW.

And it always helpful to unplug electrical connectors and plug them back in. The wiping motion of the contacts tend to clean themselves.

 

As said, bad connection = high resistivity = high heat.

I'd take that cleaning regimen a tad farther and replace anything corroded too badly and then hit all your conections with dielectric grease once every, or every other, season.

I wish I could go back in time and give myself this advice when my bike was new.

 

CRC Electrical contact cleaner (available at walmart, auto parts store) works very well for cleaning contacts. I usually blast a connection out with the high pressure spray, then repeatedly insert/remove the connection as LGN suggests. After all that liberally apply dielectric grease to both female and made ends of the connector (I literally flood the connector, so that when I push them together I've got grease spewing out which can be wiped up).

 

It doesn't take much resistance/corrosion in a higherish current connection to quickly turn it into the equivalent of a soldering iron. Power (watts) = amps squared * voltage so in say a connection carrying 25 amps, just 0.05 ohms resistance makes over 30 watts :flame:

 

Wade, all the comments above me are good. Lets not take from that. Instead, lets focus on getting the bike back running.

First, your connector needs dielectric grease in it. You need to buy some. Next we need to eliminate some variables. Get a meter, and check your battery. You need about 11.6V to about 12.2 or 12.4V. Next you want to check your starter solenoid. You can bypass this by the ole’ screwdriver over the contacts trick, and jump it out.

So, lets start there, and see if we can at least get power to the bike, and then lets work on getting her cranked.

Also, you should know, your bike has two Main Fuses… and then the fuse panel. Please check ALL your fuses.

 

I usually use a copper electrical connection grease on highish current contacts and then silicone dielectric grease on the wiring and connector around it. Dielectric grease is great for keeping water and crud out of the connection and it is non-conductive.

 

I want to thank all of you for the great advice. It was in fact a bad/corroded connection. Which one I'm not entirely sure but I stripped the fairings and cleaned/greased every electrical connection on the bike including the battery terminals and grounds. After that she started right up. I went on a 60+ mile ride yesterday and I can even feel a difference in performance. I'll definitely not let that go unchecked again!:thumbsup:

 

Good Job Wade. Well done.