she wont rev out...

[Grunty-Motor]

Need a bit of help from you guys. finally had the chance to take out my recent purchase (89 500) and after warming up, i gave it some stick  - but it gets about 1/2 way through the rev range and starts stuttering. doesnt feel electrical - more fuel. seems to have plenty of power down low and will lift in 1st/2nd.

it wont rev out in any gear. Some background;

mains - 170
second - 58
needle - middle
air - 1.5 turns out
double base gasket fitted (previous owner wanted it easier to start)
FMF fatty pipe
Tried setting float height - could understand my Clymer manual - the picture shows the point at the needle valve closing - but where do i measure?
checked the timing marks and they are at the edge of the 3 allowed marks
KIPS valves are free to move (took the little plastic cover off and it moves in and out)
standard ngk plug - brand new - so no colouring yet
reeds are fine
nothing in trans. oil
air filter clean
i'm at sea level and temp is 15-20deg.
she starts fine and idles perfect.

it really feels like there is not enough fuel - but even with a wrongly set float, wouldnt it rev out in atleast 1st?

anyone got any ideas?

[Mick]

it really feels like there is not enough fuel - but even with a wrongly set float, wouldnt it rev out in atleast 1st?

anyone got any ideas?

Gear selection has no impact on the float bowl, or otherwise how much fuel your motor is consuming.  All the carb knows is air velocity.  Sounds to me like  you might have more problems than you think?  It should loft the front end quite easily in 3rd and 4th as well.

It sounds to me like the reeds have hairline cracks.  I know you said they were good, but be sure to inspect them with a fine tooth comb and magnifying glass (figure of speech).  Also try a leak down compression test.  It sounds to me like you're down on power everywhere.  My '89 lost it's electrofusion plating and caused all kinds of problems.  If you catch it early it could be as transparent as a top end rebuild and replating in your case.  Aside from that go with your instincts.  If you think it's lean richen it up...see what happens.  Your jetting sounds in the ballpark by my recolection.

[Grunty-Motor]

this is my first 500, so i dont have much of a bench mark - but there seems plenty power low down. it just wont rev out.

looking up the exhaust port seems to suggest piston/barrel ok (from the little i see).

reeds looked new - will have a closer look though.

anyone know the size for the flywheel puller? (or a UK Supplier)

[Grunty-Motor]

can someone confirm - flywheel puller = M27x1 - left hand thread?

[Jopiz]

If flywheel is made by denso im sure its m27x1 lefthanded thread. Anyways its the most common thread for flywheels. Nearly every bike from pitbikes to kx500 uses the same puller.

-J

[snoopjonnyjon]

Sounds similar to how mine ran when I was running too much oil in the premix. I started running at 40:1 and all my problems went away. It took a while though. Had to just hold it WOT for about a mile before it cleared out. Its worth a shot, since it's about the easiest thing to try.

http://www.kxriders.com/forums/index.php/topic,5754.msg44027.html#msg44027

[Grunty-Motor]

too much oil? that sounds plausible - it is kicking out goo at the exhaust/silencer connection - and its only been running about 15mins!!!

think i am a little richer than 40:1 as that is what my RM250 is on. i'll try 50:1 and go canny on the throttle and see if it cleans out then drop it back to 40:1.

[Grunty-Motor]

last request (for the moment....)

where do i measure the float height - manual says 15-17mm but the picture aint that clear.

[Jopiz]

There you go! http://www.allthingsmoto.com/forums/f-15/how-set-your-motorcycle-carburetor-float-level-more-commentary-13608/

By the way did you happen to change to ATF type F or similiar from normal 10w30 or 10w40? 

-J

[fredodido]

hello grunty motor!

well it seems we are in the same boat

i just got a 1994 kx500 a few days ago and it will not rev out, lots of low end.  as for the mixture, i'm running 40 to 1 like the last owner, same proplem... my bike sat for 4 years in a barn when i bough it. it started after 4 kiks, and idle fine. the two problems i have is the last 70% of the rev and after opening it wide open it will do this funny thing where it is like the trotlle comes on and off by little sharp sequence and eventually stop and idle fine.

so far i have check and clean carb, float... everything is fine... timing look ok even to the clymer manuel is not so clear about it. spark plug is new and gap ajusted...

so what are the reeds your talking about? and how do you check the intake valve and exhaust?

maybe between the two of us will get them to go like they should, stupid fast...

it is my first 2 stoker, so all new to this.

[Grunty-Motor]

There you go! http://www.allthingsmoto.com/forums/f-15/how-set-your-motorcycle-carburetor-float-level-more-commentary-13608/

By the way did you happen to change to ATF type F or similiar from normal 10w30 or 10w40? 

-J

cheers J - my floats are sitting too low. hope thats the issue.

And, yes, i am running 50/50 ATF & 10/40 - why you ask?

[Jopiz]

Im just asking because i had same thing a few week ago. In my case the viscosity of the ATF type F oil was so big it came through the smallest imperfections into crankcase. I re-surfaced my crankcases and problem solved! I thought it was the crank wet seal that was leaking but it wasn't the issue. Previous owner used normal motoroil in the tranny. Its a lot "thicker" than ATF F.

Adjust your float level and post us some info how it runs. Try switching normal 10/40 if float level doenst make it run any better.

-J

[fredodido]

well well,

i found my problem...

my exhaust valves are so for of carbon, nothing is moving ... so i decoded to do a complete buttom and top rebuild. this way i start fresh. and i also think it is the cheapess way to go long term.
i already took the engine out, everything look very good, no bad surprises...

so hope you find your problem soon.

[Grunty-Motor]

good to hear - it might be a bit of work, but atleast you know the cause.

[Grunty-Motor]

bit of an update (been struggling for time.....)

1. float bowl set proper = no difference
2. new carb slide (old one has ridges in it but i thought it was ok) = no difference
3. changed tranny oil back from ATF to 10/40 = no difference
4. fitted coil from my ktm - it now revs cleaner, but there is no real power there

PLUS,
coolant coming out of overflow = weak rad cap or head gasket probs?
plug is a bit oily - maybe its cause its been running crap for weeks?
its surging on the over run

next step is to get a kx coil and i'll run it a bit longer incase it needs clearing out (clutching at straws me thinks)