VFR 800 2006, Main fuse B keeps blowing

[matsgone]

Another VFR electric gremlins story...

 

Here is the summary,

 

I own a 2006 VFR 800, 30000km, just put 6k km this season, all great.  Then it stalled, main fuse B blew, I replaced it, it blew again about 8km later running at 50-80km/hr in a +15C morning.  Parked it at home, went to work with the SUV.

 

Later that night, I ran the bike at idle for +-10min, the Main fuse B stayed cool.  I then revved up the engine a bit up and down fo a few minutes, the fuse started heating, I kept revving up and down for a few more minutes, maybe 5 min total, and the fuse got hot.  

 

Obviously the main fuse B have had some non OEM wiring done, just by the look of it.

 

I have printed the wiring diagram to start checking things out tonight (weather permitting...no garage....ya I know...)

 

Anyhow, do you have an idea to pinpoint my troubleshooting?

 

I do have a multimeter and electrical background.

 

Thank you much!!

[DannoXYZ]

We need to look at actual wiring you have.

So take factory diagram and add circuits for non-OEM stuff.

Then just looking at it, some areas to test will be obvious

Along with fix.

[matsgone]

Well the only thing the previous owner did is replace the wire on both side of Main fuse B with a bigger wire because it was showing signs of having overheated at some point.  You can see on the pic where his change connects to the OEM wiring, blue crimped connectors.  He sais he only blew 2 fuses on very hot days during the 6 years he has had the bike.  

[DannoXYZ]

Well... those wires are plenty large for transmitting 30-amp. Most likely extra flow from short somewhere was heating up wire. Rather than finding short and doing proper fix, PO just upsized wire. That's NOT proper fix and would be like you installing 40-amp fuse now.

 

Best to track down short. It's obvious there's one from PO's work. Might as well fix it properly now rather than kicking bucket down road for next person to deal with.

 

This is wiring manual I use. Pro-motorsports, aerospace and military wiring is done a certain way for performance, durability and reliability. It's always possible to improve on stock-wiring, and I prefer to go other extreme. If it can be done better, I do it.

[Grum]

17 hours ago, matsgone said:

Another VFR electric gremlins story...

 

Here is the summary,

 

I own a 2006 VFR 800, 30000km, just put 6k km this season, all great.  Then it stalled, main fuse B blew, I replaced it, it blew again about 8km later running at 50-80km/hr in a +15C morning.  Parked it at home, went to work with the SUV.

 

Later that night, I ran the bike at idle for +-10min, the Main fuse B stayed cool.  I then revved up the engine a bit up and down fo a few minutes, the fuse started heating, I kept revving up and down for a few more minutes, maybe 5 min total, and the fuse got hot.  

 

Obviously the main fuse B have had some non OEM wiring done, just by the look of it.

 

I have printed the wiring diagram to start checking things out tonight (weather permitting...no garage....ya I know...)

 

Anyhow, do you have an idea to pinpoint my troubleshooting?

 

I do have a multimeter and electrical background.

 

Thank you much!!

 

Hi Matsgone. Welcome to the forum.

 

On a 6gen that Main Fuse B is often referred to as the Fi Fuse. It purely supplies power (via the Engine Stop Relay) to all Fi stuff along with the ECM. What that means is, its NOT a power line you want to mess with by adding accessories etc. Main Fuse A would be best used for that.

 

The repair work on Main Fuse B looks O.K. Don't know what the heck that other black fuse is with the strange cut black wires is???? Suggest if it's not used then remove it completely.

 

I'm suspicious of your Charging System as it's the only other thing that hangs off Main Fuse B (assuming you have NO added accessories).  If you can run your bike long enough to see what the charge voltage at the battery is doing that might tell a story.

Check the voltage at idle and 5000 rpm. You should be seeing in the order of 13.5 to 14.5v. If you're not seeing this voltage or the voltage falls off at the higher rpm then you have a Charging System Issue. The R/R can develop issues that can take out that fuse. Revving the engine and having the fuse blow is also an indication something not being right with the charging system.

 

Have a very good inspection of both the Stator Output plug and socket going to the R/R with the three Yellow wires, as well as the R/R Output plug and socket. Both of these items suffer badly from overheated/stressed hi resistance joints over the years. While you're at it a proper check of the Stator for shorts to Ground and AC output voltage should be done. You can also download the full Service Manual from this site, that will give you extra information regards the Charging System.

Do a search in the forum for "The Drill" it will step you through a good check out of your charging system.

 

So, if you have a charged battery you could unplug both Stator output and the R/R output from the bike and run up the engine as you've done and see if that fuse doesn't blow. If you need to run the engine longer you may need to remove the headlight fuse (Sub Fuse F 20amp) to give you extra battery capacity. If you're not blowing Main Fuse B, then that points to the R/R being the culprit.

 

Good luck 

[matsgone]

Ok perfect, thanks for pointing me in the proper direction.  The other wire+black fuse you mentioned was added by the former owner for recharging the battery while being in the storage in the winter.  It is my plan to remove it.  It has been pouring rain so I havent had time to recheck anything but will do this weekend.  Thanks again for your help, greatly appreciated.  

 

DannoXYZ......40 Amps fuse.....now thats a great idea, if all else fails I will definitely go that route lol!!