Skip to content

Time for maintenance, but first let’s ride

October 8, 2006

This morning’s ride went to Madison Park, and the Tully’s coffee place at the bottom of the hill. This is a rather nice ride, crossing the Fremont Bridge to head east on 35th (34th once the construction is done), around the edge of Lake Union to the University of Washington, across the University Bridge into Montlake and the Arboretum before turning east on Madison Street (Note to local TV newspeople: the Avenue is in New York City).

The ride began with 74 miles on the clock. Steve said to change the spark plug at 100 miles. Previous experience has shown that this just saves you a lot of headaches and helps the bike break in properly. Spark plugs are cheap. Why not?

After stopping for lunch at Dick’s in Queen Anne, the odometer showed 90 miles. I had wanted to spend a few minutes on Westlake Avenue, which has nice, smooth pavement. At least until you get to Mercer Street, where it’s all torn up for… something. Still only 92 miles. A light bulb turns on: take a right at The Mercer Mess and go almost all the way around Lake Union.

Bingo! I pull into the garage with exactly 100.8 miles showing. Time to get to work!

The PX 150 owner’s manual sez the required spark plug is a Champion RL82C. Since the closest auto parts store doesn’t sell Champion plugs, they gave me the equivalent Autolite plug, a 4092. Steve’s pre-flight briefing included Cowl Removal and Replacement 101. Take off the one on the side with the kick-starter, since that’s where the engine is.

Heeere’s the spark plug!

Look closely at the center of the above photo; you’ll see the spark plug peeking out of the little hole once you remove the rubber boot (carefully!). Oh, grab the fat part of the boot, do not yank it out by the wire.

The little tool that comes with the bike is adequate for removing the plug… use the screwdriver as a lever by inserting through one of the many holes to a corresponding hole on the opposite side. Or get yourself a spark-plug socket. These are not expensive, and are not only the exact size you need, they have a rubber insert that prevents damage to the porcelain section of the plug.

Do check the gap on the new plug before installing it; 99% of the time it’ll be fine, but if it is off, you won’t get a good spark, and your engine won’t run right. You check this with a feeler gauge; a good set will cost only a few dollars at any auto parts store. These are especially good to have if you have a vintage scooter and need to set points gaps. The correct gap for whatever brand of spark plug you choose is .024 in.

Now we come to the crucial part–threading the new plug into the hole. Your life, never mind your engine, will be ruined if you cross-thread the hole, so be very, very careful. The plug should spin in easily, by hand. If it doesn’t, adjust the angle until it does. If you do this right, you should be able to get the plug almost all the way into the hole with your fingers. In fact, it doesn’t hurt to back it out and thread it in again. You cannot be too careful here!

Once it’s in, tighten the plug with either the socket from the tool kit, or your spark-plug socket attached to a ratchet. You don’t need to reef on this thing, snug will do nicely. Next, replace the spark-plug wire. You will notice a fork-like connection at the end of the wire. This goes on the metal top of the spark plug. Make sure you install it postively, because if you don’t there will be no spark. Then wrap the rubber boot around it.

Put the cowl back on, remembering that the brass hook needs to go into a hole in the flange on the inside of the cowl. Once the cowl is back on, check your work: the bike should fire up and run normally. If it does, good for you! If not, start over. Favicon

  1. Bob Brown permalink
    October 8, 2006 5:13 pm

    Thanks, Orin! I’m due to change my plug now; your account and pix will make it that much easier!

  2. Gordon permalink
    April 19, 2007 9:38 pm

    As fast as you can, get an NGK plug and throw away everything else you have. That stock Champion plug on the ’05 PX150 is nothing short of an insult to the bike. I have no experience with Autolite but you still owe it to yourself to buy an NGK. I use the colder heat range NGK with no resistor, model B7HS, but then I have to drive WOT everywhere because I live in a remote area. The hotter plug (B6HS?) might work better for driving in the city. I got my plugs (I always keep 2 spares in the glovebox) from Scooterworks but you can probably buy the model you need just about anywhere. The resistor version, which is a different part number, will work fine but Scooterworks said the non-resistor version performs better, which didn’t surprise me any. I also recommend using a light coat of antiseize on the threads to prevent any plug from trying to become a permanent part of your cylinder head.

  3. April 19, 2007 9:44 pm

    Gordon, thanks for the info. I did install an NGK B7HS and it made a noticable difference. In case you didn’t know, any time a spark plug has an ‘R’ in its designation, it means the plug has a resistor. This is necessary to suppress the noise that would otherwise come through a car’s audio system. Since a PX has no audio system (at least mine doesn’t!), radio noise is not an issue.

Comments are closed.