15A Ignition Fuse in 10A spot

Does anyone know off hand what damage a 15A inline blade fuse will cause in a 10A Ignition slot? I just replaced the fuse box with the blade style from chacal, and found that instead of a 10A glass ignition fuse in the box, there was an 15 A inline blade fuse with two female plugs in it just floating around the harness.
I'm just starting to get the bike back together, so I haven't had a chance to find any problems, but I was wondering what I should keep my eyes peeled for.
PS: I've got the Haynes Manual, so walking me through the possible fault path would be awesome.

 

Get rid of the 15A fuses, unless they are in the main power feed line (probably not). The 10A circuits are designed to carrya maximum of 10A (and it's a stretch at that, really) and allowing 15A to somhow get through it is a nice way to burn up your dash computer or your entire bike.

By the way, the 15A fuses were probably installed to "compensate" for the fact that the 10A fuses kept blowing, meaning you had better start looking for shorts or preparing for other odd problems on that circuit(s).

 

Oh the 15A is gone...don't you worry about that. I said I used your fuse box, which came nicely assembled with the proper fuses and the sticker installed (I ordered it of course) :wink: . The whole harness is off the bike and I'm working on cleaning it up and reinstalling and just wanted see if anyone knew of anything specific on the ignition circuit that wouldn't like more than 10A fed to it so I can keep an eye out for a problem.

BTW, I'm sure its obvious, but this was a PO's doing. Hopefully, the glass fuse holder just broke off, and it was replaced with what ever was lying around. *hopefully* :roll:

 

Okay, but also be aware that on your bike, there IS a separate 5A glass fuse in one of those semi-clear plastic "snap open" 1960's type of in-line fuseholders, on a blue wire I think, going to the computerized dash.....

 

Yeah I saw that one in the headlight bucket. This was definitely a replacement for the 10A ignition fuse. I guess "floating around the harness" is a little vague. The wires came out of the same bundle as the one going into the fuse box, right colors and everything (I don't have it in front of me but I believe it was Br and R/W), but these two wires were just hanging out outside it with a 15A fuse plugged in. At least they weren't just spliced with a wire nut...right? :lol:
While I'm at it, should I be replacing the inline 5A glass fuse (it was in the headlight) with a blade type or is it recommended to replace with a 5A blade fuse?

 

I replaced mine with a water-proof 5A ATC blade fuse when I did the fuse block. Good idea to get it done while you are thinking about it.

 

Don't know about the stock ignition system, but mine peaks (current-limited in the coil drivers) at 7A per coil during dwell. Other ignition drivers, like the Bosch BIP373 run as high as 16A before current-limiting.

At low RPM's, where dwell from TCI is especially long, you might find that you're stressing that 5A fuse a bit. Might want to carry a spare in case it finally decides to give up the ghost somewhere inconvenient.

 

I got the 5A ATC fuse holder from Autozone, but it's got 12 gauge wire, and I think the wire I was trying to connect it to was 16 or 18. I already soldered it, but was this a bad idea to solder dissimilar wire guages ? I'm not even sure how all of this with fit into the bucket.

 

As long as your soldering is good, mixing in a heavier gauge wire than original is fine.

 

You can use larger gauge wire to connect to smaller wires but never the other way 'round. Amperage rating is less for smaller gauge and using a smaller gauge wire with larger supply wire is asking for a fuseable link to happen. Just be sure that your soldering job is clean and sound. Cover with heat shrink (environmental type is a great idea) and you should be good for years.

 

Yeah I knew about the different current capacity of different gauge wires, I just wanted to make sure that there wasn't something wrong with soldering different gauge wires like there is with crimping.

Here's to hoping I did a good job soldering. I have a little experience and read up a bit, but my tools are old and a bit lacking. It sure took a while to heat up the 12 gauge wire! (nothing was connected) Twisting the wires takes some planning to.

SQLGuy, I don't think the 5 A fuse is involved with the ignition system. The Ignition Fuse I mentioned in my first post is the one from the fuse box. It should be a 10A, but the PO wired and "inline" fuse (two female connectors wired directly to the fuse) that was 15A. We went down the 5A path because chacal wanted to make sure that I knew that there was supposed to be an inline fuse somewhere else. So the ignition fuse will be 10A