Idle Dies Down

[Paul]

Tomasaki, have the bottom end pressure tested. You're showing the classic signs of a leaking seal on the oil side of the engine. Also perform a compression test to ensure your compression is between 110PSI and 170PSI.

[tomasaki]

Thanks Paul, But how do you check bottom end pressure???  I've never done a compression test either but it seems like you would just hook a gage to the spark plug hole and crank it.

Tom L.

[Paul]

Thats correct, a compression tester plugs into the sparkpulg hole and you kick the engine over until the pressure no longer rises on the gauge. This will tell you if you're in the service limits of: 110psi - 170psi.

Everytime I do a topend on my bike I pull the piston and put the jug back on the engine. I have a pressure gauge that threads into the sparkplug hole and a rubber stopper (gotta love Home Depot ) that seals the exhaust port. I have a flat plate with a valvestem (like your car tire) in it that i use a bicycle pump with to pressurize the cylinder. Flat plate bolts to intake side of the cylinder. A couple pounds (ehh, more like 7 or so) is all it takes and then you just watch the gauge for bleed off. If everything is good then there shouldn't be any pressure bleed-off.

Good luck and we're here if you have more questions.

[tomasaki]

Thanks again Paul!!!  That all sounds easy enough!  I'll call around and see if I can find a compression tester.  The bottom end test will have to wait until I'm due for top end.

How does this all affect the idle?  Other than the idle dying off, and the spark plug always being black, the bike performs outstanding.

[jdv500]

hello ,
 my 01 500 do'es the very same thing. as soon as i let go of the throttle it will pulse and rev on by itself... thanks, jdv

[jdv500]

my 01 500 will pulse and surge by itself evrytime i let the throttle go after a straight and level run,
with the gas shut and rolling, the revs will bounce up 3 or 4 little peaks and the bike will surge forward in sequence. any help would be great thanks.!! jdv

[rradar]

Tom, After trying everything, plugs, all jets, oils, ratios, etc. I finally made my own Idle Screw just a few threads longer than stock and shaped the end on my bench grinder-like the stock screw. Idles nice, I can adjust it a lot better now. It doesn't surge and runs clean due to all of the jetting. I run Maxima Super M at 40:1 with a BR7EVX and 92 Octane Pump.
Rick K.

[doordie]

John,
Good for you with the rebuilt and you don?t need 2 gasket, I promise!
(The moose is something around 10mm)

//doordie

[KXcam22]

Joseph,
  Unfortunately, that surging seems to be quite normal when the jettting is good.  Mine does it just like you describe, maybe worse.  Gowen did a lot of testing and the surging only seems to go away when you are too rich.  I doesn't bother me when I ride so I have got used to it. Probably not the answer you were looking for. Cam.

[jdv500]

yeah,
 i often relying on the engine braking and during this is when i feel it . thanks, jdv

[Torch654]

Just a quick question I get some small surges under these conditions (hi speed to chopped throttle) The bike only accelerates for one "pop" and not very often. The odd thing is my jetting is a Little rich. I was thinking a worn slide? Its not a big deal I was just looking for opinions.

[GDubb]

The surging on the 500 is normal... you can search for posts on this subject as there are a ton.

[Torch654]

Yes I have been reading......but for some it seems to go away when jetted rich. I am jetted rich and it is still doing it, so I was wondering if my thoughts on a worn slide hold water.

[hughes]

Maybe carboned up power valves(sticking)mine is a little rich but pusled and surge a little bit but after I cleaned and re-lubed the valves problem solved.