Idle Dies Down

[tomasaki]

I have a hard time keeping my idle on my '01KX500.  It always slowly fades down, especially going down a long slow hill with the clutch in.  I always have to keep revving it.  Anyone else have this problem???  I mainly woods ride.  Alot of slow stuff.  I have the main jet at 165, clip at top #1 notch, 52 pj.  The idle screw is only out 1 turn from seated.  If I turn it up more it runs away sometimes.   The performance is great!!!  My BR8EG plug is always black though.  I can't go any leaner.  If I lean the pj, it surges, If I lean the main in dies at full throttle.  It's very crisp and responsive.  It just won't idle for long. Any suggestions???  I'm thinking of trying a hotter B7ES plug since I mainly ride at low RPM's where I can control the power.  Thanks for all suggestions.

Tom L.

[yzmike]

Yo Tom, whats your altitude? And having the clip in the first notch is bad. What was factory setting?

[tomasaki]

yzmike:  I don't know my altitude here in Western PA, but I think it is fairly high.  There are alot of mountains around.  The factory main was 168, pj60, clip in the center.  With the factory jetting, I could not let off the gas for a second without it fouling horribly like I had the choke on.  If I don't keep the clip at the top, it loads up from bogging around too much in the woods.  It's done this since it was new from the factory.  It's totally stock other than the FWW.

Tom L.

[gwcrim]

I don't know my altitude here in Western PA...

I'm 40 miles west of Da 'Burgh and I'm around 1000'.  I have a  170 main and a 52 slow jet and don't have any fouling problems.  I even got it to idle with a 60 slow jet, but it would eventually die.  I have no idea what needle is in it though.  I assume it's marked on it.  I 'spose I should look.

Ya might want to take the carb off and clean all the passages, check the needle & seat for wear, and reset the float level.

[yzmike]

Lets look at some contributing factors, what type of 2 stroke oil do you use? what ratio? Also sounds like to live near Pittsburg, or Kittanning. This could call for jet change also. I know you will find the correct combination. YZ Mike

[tomasaki]

YZMIKE:  I use Mobil 1 synthetic 2-stroke oil at 32:1.  I live about an hour east of Pittsburgh at the base of the Laurel highlands.

GWCRIM: Does your spark plug stay clean?

Tom L.

[Rick]

Dump the EG plug and switch to a BR8EVX before you monkey with anything else.  I have never gotten a bike to run right with the EG, so I always switch out the plug first thing on new bikes.

Look at it this way, for less than $10, it's worth a try....

Good luck.  Problems with our toys don't make for happy boys...

Rick

[tomasaki]

Thanks Rick!  I'll give it a try.  What is different about the BR8EVX plug?

Tom L.

[John]

I have had the very same problem with my 89. I have rejetted it until I actually had it to idle - but was way to lean, so back on square one.

This weekend I changed the piston and mounted a home made spacer kit (17 mm). The bike now idles.

This could however have been caused by the fact that there is now only one top head gasket instead of two. (The previous owner probably had some leaking problems...) The compression is higher and the bike is more responsive - loads of torque   . I am going to take away the spacer once I have received the proper one from Moose. I will test and see if it was the higher compression or the spacer who did the trick. Moose deliveries to UK sucks so expect 6 weeks minimum...

/John

[yzmike]

You can tell that these guys have experience in solving complicated problems, so truthfully. the only thing I can add is DEFINITLY use a premix oil that can run at 50 to 1, this alone should clean up the plug! I will buy moose spacer also. Keep writing about everthing you try.

[tomasaki]

Thanks Guys!!!  It'll be an easy thing to try to run the Mobil 1 MX2T at 40:1 instead of 32:1.  I guess 32:1 is only necessary if you're running hard.  I just fart around in the woods at low rpm's.  I'll bet if I run 40:1 with a BR7ES plug, it should stay fairly clean.  I'll let you all know.

Tom L.

[Paul]

Tomasaki, I've run 40:1 on a BR7ES for 18 months. The bike still fires up on the first or second kick. I use Maxima Super M

[tomasaki]

Thanks KX500!!!  I'll be trying this 40:1, BR7ES combo this weekend.  I'll let you  all know how it works out!!

Tom L.

[gwcrim]

I had a chance to ride this weekend with the new 52 slow jet.  I run MX2T @ 40:1, 1.5 turns on the idle mix and a #8 plug.  When I got home I let the bike sit and idle and idle it did.  No sign of dying out at all.

[tomasaki]

I tried the 40:1 mix with b7es plug and didn't see any difference.  The plug was still black at the end of the day.  Performance was good as usual.  However, it still won't idle for long no matter what pilot I put in.  I've tried 48, 52, 55, 58, 60, &62 pilots.  The only difference I get is runaway revving with less than a 58.  I'll stick with the 58 for now.  I cut some of the spring off of the idle screw so I can turn it in further.  This seemed to give me  some more idle.  I'll have to see next ride.  The problem with having the idle screw in so far is the rpm's don't want to come down right away when I let off the gas.

I took out the reed valve and cleaned it. It was a little gunked up, but that didn't fix it either.  Would a lighter reed valve help???  Like low tension carbon fiber maybe???  I was just thinking maybe the stock reed valve is a bit heavy and doesn't respond well at an idle.  Does this make sense???

Tom L.