Topic: Please help me with my Mother in Law's Bike (Eliminator 125)

[Jayelwin]

Everyone on this forum is so good with bikes in general I figured I'd try to get some help with a problem bike

So I bought my mother in law a Kawasaki Eliminator 125. It's about 8 years old and in great shape with only about 800 miles on it. It definitely has no real troubles. It's a small cruiser with a single cylinder and a Mikuni BS28 CV carb with a diaphragm controlling the slide.

So the problem is I can't get it to idle at all. When you let go of the throttle it stalls. I figured I needed to up the idle screw to crack it open more at idle but something odd happens. When I raise the idle it suddenly goes from sputter and stall to 3500 RPM once I reach a certain point. Then I back down on the idle screw and it goes right back into sputter and stall mode.

It rides around great. When I'm on it I have no problem because I can keep it goosed at stops. When you're actually going it has no trouble at all - appropriate power, smooth through the entire power band. My MIL is a VERY (did I say very) new rider and she's constantly stalling - she needs a reliable idle.

The bike was owned by a guy with Alzheimer's so it did sit for a while. I pulled the carb and pulled the jets and made sure they were perfect. The idle jet is not gunned up at all - I cleaned it with a 10x loupe and can clearly see a smooth brass passageway right through it. So jets are clean. The slide works great. I sprayed the heck out of the inside with carb de-gunk. And it looked really clean anyway - no real varnish I could see.

I can't figure out why it won't idle and why when you try to raise the idle it's either all or none - you cross some threshold with the screw and it goes from barely running to a mid range RPM. I figure there's got to be someone who can help me. Thanks.

[fmctm1sw]

Nothing like scoring points with the mother in law (or losing points  ).  I'm not familiar with the bike but have you checked basic tune up items like the timing?  Perhaps you have air leaks at the carbs?  Just a couple thoughts...

[Jayelwin]

I sprayed butane all over and got no surge (my go to leak detector). I ended up totally disassembling the carb and doing an ultrasonic cleaning. I figure if the idle jet wasn't clogged maybe something else about the circuit. Now it idles but with the idle screw maxed out. Better.

Didn't think of timing.

[calj737]

You might also give the vacuum valve a good look, or replace it. Looks like the parts fiche indicates that part as among the most purchased carb parts.

My auto mechanic taught me a trick: if you call a dealership parts dept or parts supplier, and they have inventory in certain parts, it is generally due to these being replaced regularly. On some older bikes with limited availability, these still available components are generally troublesome. This not foolproof, but an insight I often use to diagnose this type of problem (recently helped a guy with his ATV and riding mower successfully in both efforts).

[grcamna2]

It's fairly straightforward to test the vacuum diaphram/petcock