AboutBill Silver Expertise Need help with vintage Hondas from the 1960s? I am an expert with 250-305cc bikes in particular and most all of the other pre-91 models, in general. I do NOT claim to have a great deal of experience on Gold Wings, Cruisers, ATC/ATVs and dirt bikes.
Experience I have owned/ridden/maintained Honda motorcycles for 35 years. I have written five books on Honda repairs and collecting. I was a service manager for two Honda shops back in the 1980s.
Organizations VJMC (Vintage Japanese Motorcycle Club) of North America
Publications VJMC newsletter, as editor for two years and as contributing editor currently.
Question Real quick I will give you a background, I have my first bike a 1980 Kawasaki 440 LTD and when I got it, it ran great. I was messing around with the fuel selector switch and saw that it said PRI, ON, and RES. Like an idiot I assumed that PRI meant primary as in primamry tank, so I switched it over to that and ran it. What I found out later was that PRI meant Prime, so I completely flooded the engine and had gas leaking out of the overflow. So I tried to clean and dry it but I had to change the spark plugs as they were ruined and the bike did not run smooth after that. So I let it sit for the winter, all the gas had leaked out of it by the time I came back but when I started it it ran good, no gas leaking, only thing now is that it idles at about 1500 to 2000 RPMs when before it idled at 1000 or less, it's also very slow at idleing back down to even the 1500 RPMs. Trying to find out what might be wrong and how to fix it. Thanks
Answer Not my brand, but I know a bit about them. The petcock was designed so that the fuel DIDN'T drain out when the ON was selected. PRIME is for when it runs out of gas or you have the carbs apart, etc. There is a diaphragm in most of those petcocks that often fails and causes air leaks and fuel leaks.
Gas out of the carbs, indicates that the float valves are leaking and that the carbs need to be overhauled. Try some Yamaha carb cleaner with them intact, otherwise, you have to pull them off and disassemble them, clean them replace the bad bits and put them back together again.
Even if the carbs are doing okay, I suspect that the spark advancer is sticking/stuck and needs to be taken apart, cleaned and lubricated. I know some of these have points and some have electronic ignition. BOTH versions have mechanical spark advancers behind the point plate, I believe. Mark it before you take it apart, as there is a 50-50 chance of incorrectly reassembling it. With the spark timing coming in correctly, the engine idle should settle down again.
