My Kawasaki Vulcan Drifter 1500 motorcycle has always run rich, was cranky to start, and never felt “right” until it was warmed up; today I discovered why. Apparently, one of the four spark plugs wasn’t installed correctly when the motorcycle was originally assembled. It was close enough that the machine ran, but with ongoing side effects:
- Cold hearted beast – until it was warm, it didn’t run smoothly
- Very rich – it has always run rich
- Hard starting – was often difficult to start, particularly in cold weather
After cleaning up the residual goo in the offending spark plug socket, I completed installing four new plugs – being careful to cinch them down just enough to crush the washers into place. I also cleaned out the throttle body with a toothbrush and some Seafoam. The tooth brush turned incredibly black – I kept rinsing it with Seafoam, then scrubbing more – careful to clean the throttle body and the butterfly valve.
I pushed the starter and the bike roared to life. I immediately noticed that the idle sounded different – as if it were hunting for the right spot; it was idling too fast, so I backed off the idle adjustment and everything settled down. I quickly realized that the bike was idling smoothly, with the engine cold, with no encouragement from me… this is a new experience for me.
Rolling on the throttle brought a very smooth, even response from the engine. In fact, I found myself grinning and grabbing way more throttle than I should have. I’m going to need to keep a close eye on the speedometer until I’m used to the new performance. I think I'll put the GPS on the bike tomorrow for my ride to work - as a reminder.
Two odd side-effects from this maintenance: it appears that the amount of deceleration during full throttle-off is less (I’ll need to use my brakes a bit more), and I’m getting some popping in my exhaust. I think I have the fresh air injection system blocked (to eliminate popping), but perhaps one of the marbles(!) slipped? I’ll have to check it.
I’m really looking forward to getting a few miles on the bike now - I wonder what might happen to my mileage? I recently achieved 46 mpg around town - quite good for a 1500.
