Technical Q and A for classic motorcycle maintenance and repair.
Editor’s note: If you’re having trouble with that old Suzuki, BSA or BMW, Keith Fellenstein is your guy. From motorcycle tuning tips to detailed motorcycle engine repair, he can draw from a wealth of experience to help guide you to success. Send questions to: Keith’s Garage, 1503 SW 42nd St., Topeka, KS 66609, or send an e-mail with “Keith’s Garage” as the subject.
Kawasaki Eliminator 900 Electrical Worries
Q: I have 65,000 miles on my 1985 Kawasaki Eliminator 900 that I bought new in 1985. It runs like new. At idle, the neutral light, taillight and headlight oscillate back and forth from normal to dim to normal to dim, etc. Is this telling me that something is heading south with my electrics? I have a smooth idle of 900rpm. I have Excell coils and wires and a Vance & Hines advance plate added to my bike, which have really made it run much better than stock. I opened the pilots to three turns out and have had great results. Also, on a trip out west to Idaho last summer in heavy rain, water collected on the left valve cover and got into the spark plug hole, shorting out the plug. I had to use a straw to blow the water out of the hole. Can I use silicone caulking to seal the rubber plug boot, or can you suggest a way to seal the water out? If the bike sits out in the rain when I’m traveling, water pools in that area of the valve cover. — Paul Comer/Alliance, Ohio
A: It doesn’t sound like you have a problem with your ignition, just a minor problem with your lighting. Unless there’s a bad ground somewhere, my guess is that your voltage regulator is flipping on and off at that low rpm. You don’t mention any auxiliary lighting or other additions that would draw current, such as heated grips or vest. If you’ve added a load or two to the bike’s electrical system, the alternator is probably not keeping up at idle. There’s also a chance your aftermarket coils are drawing more current than the stock coils. Once you increase the engine speed, the alternator produces more than enough juice to charge the battery and power everything. You can test this easily if you have a multimeter. Set the multimeter to the DC voltage range nearest to 12-20 volts. Clamp the positive lead to the positive pole of your battery and clamp the negative lead to the negative pole. Start your engine and let it idle. Watch the meter, and see if it doesn’t jump between a little below 12 volts and a little above. Increase the engine rpm up to about 4,000rpm; the voltage should climb to about 14 volts. If it goes much higher than that, say 16 volts or so, you may have a defective regulator. If it doesn’t climb, you’ll need to check the alternator for shorted or open coils. As for your spark plugs, I don’t think I’d seal them up with silicone, as it could be difficult to remove the next time you want to change your plugs. I’d look at the engine closely and see if there are drains in the spark plug wells that are clogged. There’s an insect that loves to make a mud nest in any small hole. I’ve seen several carburetors with these nests built where the drain screw comes out of the bowl. If that’s not the solution, perhaps you could find rubber washers at the hardware store that would fit under the plug connector and help seal the valve cover. MC