We had a 420 in this week with badly chewed wiring. It is the second time, the first was the wires from the back of the engine for the speedo and gear position indicator, which threw the ES system out. This time the rats had been in the battery box and chewed the relay and ECU wires. I've soldered them up and the bike runs OK. As the owner seems incapable of keeping the rats off the bike, is there anything I can spray on the wires to stop the rats chewing them?

 

Have plenty of sprays like this online,but don't know if it's feasible for you across the pond.Buy Rodent Repellent Online | Critter Out Shop Plus read that rodents hate the smell of peppermint. Here's one article on how to deter them.

1. Put 5 drops of peppermint essential oil on a cotton ball
Place by doorways, window seals and any cracks
2. Grow mint around your home. Planting mint around your house will create a protective field.
3. Put 25 drops of peppermint essential oil into a spray bottle with 8 ounces of water
Spray around baseboards, windows, doors to repel them and if they wander around your house.
4. Soapy peppermint oil spray:
Mix 1 cup unscented baby shampoo and 25 drops of peppermint essential oil.
Fill a spray bottle with the mixture and spray on areas and surfaces where you wish to repel them like basements and garages.

I've had my share of chewed wires over the years from farmers leaving their machines in barns with hay,feed,etc and field mice would still eat up wires. Some owners have even gone as far as to leave packages of rat poison pellets on floor boards and around machines,but don't know how well that works.

 

Oddly enough, I had another 420 with rodent damage yesterday. The starter didn't work, took the battery box top off, (not easy with a slug pellet sprayer on the back) and the thin wires for the solenoid had been eaten off. That was one of the problems with the other bike, so those solenoid wires must be tasty. The battery box had some slug pellets in it, so that doesn't deter them. I will try peppermint oil.

 

Reviving my old post here. I have had three Honda 420s in a week with rodent damage to the wiring in the battery box. Old model is an understandable design mistake, they obviously never thought that the battery box lid forms a shoot to funnel anything that drops off the rear rack into the battery box. Standard modification by dealers was to put a sheet of soft plastic across the top of the box, to catch and deflect the debris off and down between back plastic and airbox. This “sort of” works. However to make it even worse when Honda came up with the new model in 2014, is outright stupidity. The “shoot” is lower, so goes down below the rim of the battery box, ensuring that the plastic sheet mod can’t work. As farmers carry leaky animal feed bags on the back rack, the battery box rapidly fills with wet feed, dirt and water, which attracts rodents, who then bite the wires. The acidic nature of the maggot infested gloop ensures that the bare copper wires turn to verdigris even if the rodents have not bitten right through. Gamekeepers bikes are even worse, they carry wheat, often fitting a dispenser for spreading it, on the rear rack, so the battery box fills with wet and sprouting wheat. The two new model 420s both had the red/black wire under the fuse box chewed, I soldered them up, then made and fitted a foam rubber “bung” between funnel and seat, we will see if that helps. An old model 420 was a lot more tricky as it didn’t charge. Tried a new regulator, still no charge, tested wires to alternator, they tested as OK, tested wires from battery to regulator, OK. So checked workshop manual, it mentioned the relays in battery box as a possible fault. Cleaned out all the mud, which hid them completely, and found a wire to a relay had tuned to verdigris and broken, un-plugged the relay and found a pin on it had also rotted away. A new relay and bit of wire soldered into the loom meant charging is restored.