03 vfr800 main fuse b keeps failing

Hello vfrworld members,

I just purchased an 03 vfr800 with 9k its the abs model. It seems these bikes have problems with the regulators and I think I may be having one. I rode the bike on the highway for 25 min the other day at a very spirited pace. I got off the highway in the bronx and about 5 mins after getting off the highway and I roll up to a friends apartment and the bike died. The coolant temp on the highway is around 175 but when I was in traffic it went all the way up to 220. Anyway I found main fuse b had popped. I changed it then the bike started again but popped the fuse again minutes later. I tried a few more times without succes then decided to get the bike towed home. When I got home I put another fuse in and it didnt fail. I checked the charging system with the voltmeter and it seems within spec. After that I rode the bike 2 times for about 1.5 hours each time. It didnt fail either time. I pulled the seat off to check the fuse and found the plastic insulation to be melted but the fuse hadn't popped. I had a dollar store 10amp fuse so i though maybe this is the problem. I found the manual and It calls for a 30amp. So I put a 30amp fuse of good quality. The fuse and wires to the fuse connector are still getting hot though. I checked the voltage at these wires and it is around 14v and the amperage is around 6 amps. Seems ok but now I am afraid to take the bike out for a ride considering it may fail and if the wires are getting hot there may be a problem. I dont want to ruin the ecu. I'm hoping one of you guys could help me solve this issue. I could use a wiring diagram. I was thinking about purchasing the ricks upgraded regulator. Any and all help is very appreciated.

 

Oh yea the rectifier regulator is hot to the touch

 

Hot regulators are never a good thing.

Let's go through a few things first.

1. There were recalls issued on teh 2002 to 2006 VFRs, including a wiring harness. Find out if these were done. You Honda dealer shoudl be able to run your VIN, or call Honda. Sometimes the VIN sticker was punched indicating the work was done.

2. Why did it have a 10amp fuse when it called for 30? I'm not following if you put that there or if it was there and you swapped it out? Did the previous owner hack into the electrical?

3. Did you check your volts with a fully charged battery, then at idle, then at 5000rpms? What were your readings?

4. Your temperatures are normal. These bikes run HOT. Your fan should come on at about 221, give or take a degree. It should stay on until you're back down to about 212-214. 175 on the highway is actually pretty cool.

Obviously, if your popping fuses, you got some sort of issues. I'd start by checking your earth/ground. Pull apart each spade plug in clip and check for signs of burning or melted wires in there. Sometimes its not that obvious.

There are plenty of options for R/R, but the Ricks unit has worked fine for many of us (I'd strongly recommend a VFRness as well. Check out Wire My Bike). Do a search on this forum and you can find enough info on R/R to make your head spin.

Keep us posted, and let us know the exact volts your getting from that battery at Off, Idle and 5K.

 

Ok to answer your questions. I originally found a 20amp fuse blown in fuse location b. I wasn't sure what fuse it called for so I installed a 10amp fuse to be safe. The 10amp fuse was from a dollar store. The plastic insulation on that fuse melted but it didn't pop. I checked the manual and found that it called for a 30amp so replaced it with a good quality 30amp.

When I got off the highway and the bike was hot was the time when when it continuously burnt 20amp after 20amp. I tried about 5 fuses before I gave up and had to be towed home. After I got home I rodethe bike 2 times for 1.5 hr each. No problems with the circuit but the plastic had melted on the fuse. Only the cheap ones melted though.

Battery voltage 12v. When I checked the charging system at idle it was around 13.5v. If i revved it then let it settle at idle it would be around 14.2v. If i held it steady over 4k rpm it would rise but no higher than 15.0v.

I called Honda and they told me my bike was up to date. It had a harness changed and some valves I think(Idk she didn't seem to know that much).

So I had the issue with the fuses popping. I rode it the next day and it worked fine but melted the 10amp plastic insulation and got hot. Today I changed to a good quality 30amp and it didn't break the circuit or melt the plastic. It is hot to the touch. The r/r is hot also. I didn't have a thermometer but well over 100 degrees F.

So I am afraid of this happening again on a long ride. I pretty sure that the wires leading up to the fuse should not be hot to the touch and you are telling me neither should the r/r.

My conclusion is that when i was riding in the city the r/r got very hot and created to much resistance and popped fuse after fuse until it cooled down. Now if I am right and the r/r is faulty possibly when it is cooler it still created to much resistance and that is why the wires are hot and it melted the fuses. However I'm not even sure where the wires lead. It may not be the rectifier. I need the schematic to be sure. I do know heat means resistance and resistance means blown fuses.

Thank you for the help