[riotsk8er]

my 97 kx100 wont kickstart from cold without the help of starter fluid. the carb is tuned and good, actualy its a new carb. but after i get it going with the fluid and it warms up a bit, it will start first kick all day. as long as the engine stays warm. it still pulls the front wheel up no problem in first and second gear. the reason i dont know if it needs a top end is that i dont have a compression gauge so i cant tell exactly. the only way i think i can tell is that when the egine is warm the piston expands, causing it to have more compression and suck gas better than when cold. help!

 

[QKENUF4U]

without a compression check its all a GUESS..... but yes i would agree and yes you are correct about why it runs when hot...... get a compression guage and check it correctly (throttle wide open and kick till guage stops) maybe even borrow one from AUTOZONE ...

 

[deucer]

When it is warm, how does it run? Does it pull relatively strong? My first thought is, are you choking it to make the initial cold start... On my KX 250 you got to choke it with 1/4 throttle on a cold start.

 

[riotsk8er]

"When it is warm, how does it run? Does it pull relatively strong? My first thought is, are you choking it to make the initial cold start... On my KX 250 you got to choke it with 1/4 throttle on a cold start."

it runs pretty good when warm, like i said after its warm it will start one kick all day and keep the front wheel up in first and second. i usually try choking it at a cold start and kick it 10 or 20 times and it does nothing. after that i just spray some starter fluid in the cyllinder. once it idles for a minute or two i can turn it off and be able to kick it to get it going.

 

[nd4speed]

my quad was like that even after a fresh top end. Probably just the wrong size pilot jet in the carb or clogged jet.

 

[deucer]

Flooding. Try cycling throttle two times full before kicking. Choke and add no more than 1/4 throttle and kick start.

 

[riotsk8er]

Flooding. Try cycling throttle two times full before kicking. Choke and add no more than 1/4 throttle and kick start.

That didnt work...i honestly think its the top end. ive tried going up on the pilot jet and that just made it worse to where it wouldnt even idle and ran wayy to rich. ill just borrow a compression gauge from autozone and see what i come up with. if it is the top end what will i have to do to fix it? i know that ill have to get a bigger piston but what has to be done to the cyllinder? re-sleeve? bore?

 

[QKENUF4U]

not 100% sure on the 97's but you may get lucky and its a NIKASIL cylinder which means you can just put new piston/rings in it as long as the nikasil is in good shape.
compression check
HOLD THROTTLE WIDE OPEN
KICK TILL GUAGE STOPS
if its under a 100psi (or very close) then the top ends done IMHO.

gasket kit,
piston kit
new needle bearing
have cylinder checked (maybe ballhoned to put crosshatch back in)
take lots of pics so ya know how things went together...

 

[riotsk8er]

yes the 97's are nikasil which i guess is good for me because my budget is low. ok i havnt got the compression tester yet but ill try soon. thanks for the help guys. what should the gauge read if the top end is good? my guess is around 140 psi?

 

[QKENUF4U]

prob. not a bad # to look for... but over 100psi for sure...

 

[riotsk8er]

so what makes the nikasil good? is it harder than the piston so its likely that the piston is damaged and not the sleeve?

 

[QKENUF4U]

yes nikasil is a very hard coating... the rings wear out before the coating. but if the piston came apart and gouged the nikasil then you have to send the cylinder off and have it recoated.
the big plus is you can just ball hone it to put the cross hatch back in (not even necessary but helps the rings seat a bit faster) and throw your new piston/rings in and reassemble (if everything else is still good shape)

 

[riotsk8er]

wow thats great because it will save me tons of money if it is the top end. i know for a fact that the piston is still intact beacuse i shined one of those ultra bright LED's down the spark plug hole and it looks okay.:wink: i still have no compression tester so ill have to get one maybe today or tomorrow and find out whats up. would something like this work if i needed a top end?


Wiseco Top End Rebuild Kit Piston KX100 95-97 STD : eBay Motors (item 390040205534 end time Apr-20-10 15:49:24 PDT)

 

[QKENUF4U]

as long as cylinder is in good shape that kit will work nicely.....