My K100RS had not been out on the street for at least 12 months and thought all I had to do was replace the battery but my assumption was wrong. After trouble shooting the no-start problem, I finally figured out my fuel pump wasn't working. I looked at several different alternatives (new $$$ Bosch pump, 52mm aftermarket pump, or a 43/37mm pump). When I ran across a site (sorry, don't have it at the moment) showing how to rebuild the pump, I decided I had nothing to lose so here's my $.02 worth.
First, I wasn't prepared for the pile of black crap the vibration damper had turned into from all of the years of being submerged in ethanol. That is some nasty stuff! To take the pump apart, you'll need to un-crimp the top with pliers or a screwdriver, then turn the pump upsidedown and tap the bottom with a wooden handle of a small hammer. Once it starts moving, turn it righ tside then strike the bottom of the pump on a wooden handle to push the pump out of the aluminum housing. Take your time or you'll end up with parts of the pump all over your garage floor (ask me how I know).
Once the pump is removed from the aluminum housing, separate the top part from the armature shaft then you'll see a c-clip and a washer on the shaft. Carefully remove both then you'll be able to slide the armature shaft off, then you'll see another c-clip and washer. Remove both then you'll be able to slide the plastic thingamagig (driver?) off the shaft.
BEFORE YOU REMOVE THE SCREWS, MARK THE TOP & BOTTOM HOUSING!!! After you've marked the housing, unscrew the four screws and separate the housings and you should find 5 rollers. The pics I've seen of other fuel pumps and these rollers were pretty bad....most of them were rusted almost to a point were they probably needs to toss the pump. My rollers had a lot of varnish built up so I used fine grit sandpaper to clean them up as well as the housings. Once cleaned, I sprayed WD-40 onto everything then started the re-assembly process. When trying to mate the top half of the pump with the bushings onto the armature, I inserted the handle of a screwdriver (about 3/4" diameter) to push the bushings back, then used dental floss to hold the bushings in place. It took a few tries but I finally got everthing back together. Before you slide the pump back into the aluminum housing, make sure the housing is free of any corrosion and/or varnish buildup. Also make sure the rubber o-rings are on or you'll pump won't be able to generate any pressure.
After I got everything back together, I tested the pump.....the good news is that it worked but the bad news is it seems the polarity is backwards. When I put the positive wire from the battery to positive side of the pump (and hooked up the negative wire), the pump didn't do anything except make bubbles. But when I reversed the positive and negative, the pump generated pressure. Since my pressure gauge crapped out on me, I don't know how much pressure but will follow-up on that later.
I hate to stop here but I've had enough fun for one day. Hopefully tomorrow I'll figure out what I did wrong or better yet, I hope someone on this board can tell me what I did to goof-up the pump.
Note: I haven't figured out how to post the pics between paragraphs so all of the pics are shown after the write-up.....I'll work on making it easier to follow.
