Jump to content
Sign in to follow this  

1999 kx 250 wont fire up

Recommended Posts

Can anyone help?? ive got a kx 250 with good spark its getting gas but still wont fire up.the commpression is low at 130psi could this be my problem?? :banghead:

Share this post


Link to post
Share on other sites

thanks guys ive just checked the pipe and its all good no blockage, plus while the pipe was off i had a look at the rings they seemed ok but there was lots of oil on them,a little more than normal i would say.also the air filter is new and its all good there. :foul:

Share this post


Link to post
Share on other sites

Has it been fired up recently? Could be a gummed up carb. Try putting a little fresh gas directly into the cylinder through the spark plug hole, put it back together and see if it fires. If it does you have a fuel delivery problem most likely.

Share this post


Link to post
Share on other sites

Has it been fired up recently? Could be a gummed up carb. Try putting a little fresh gas directly into the cylinder through the spark plug hole, put it back together and see if it fires. If it does you have a fuel delivery problem most likely.

This should be the first thing u do if u have fire. Cause just cause it gets to your carb doesn't mean it's getting inside your motor

Share this post


Link to post
Share on other sites

I had a cracked and badly chipped reed that caused similar problems.

Good luck.

Share this post


Link to post
Share on other sites

So I had it running last week for an hour ride, the bike was running good fresh gas in it all ok.

I have checked the reeds they are good, tried gas in the cylinder and she still won't start, cleaned the carb checked the jets.

I am puzzled !!!!!

Share this post


Link to post
Share on other sites

So I had it running last week for an hour ride, the bike was running good fresh gas in it all ok.

I have checked the reeds they are good, tried gas in the cylinder and she still won't start, cleaned the carb checked the jets.

I am puzzled !!!!!

He mentioned he had spark.

A trick I use is to hold the throttle wide open while kicking. Usually overcomes some jetting issues. Works really good when hot. Not so sure about cold.

Being cold, if it starts, let the throttle go quickly, dont want to over rev a cold engine.

Share this post


Link to post
Share on other sites

Chubbster,

I have a 99 kx that I just got. It starts pretty good, except on occasion it takes a lot of kicking.

Other times it takes half a kick.  Strange.  I'm wondering if its an electrical intermittent connection.

130psi does not seem too low to start.

Share this post


Link to post
Share on other sites

Chubbster,

I have a 99 kx that I just got. It starts pretty good, except on occasion it takes a lot of kicking.

Other times it takes half a kick.  Strange.  I'm wondering if its an electrical intermittent connection.

130psi does not seem too low to start.

 

130 is on the low end of recommended PSI for these bikes... You need a top end (that is, if your reeds are good and you did the compression test correctly)  Compression test needs to be done HOT, with the throttle held wide open.

 

Could be bad crank seal too if I'm not mistaken.  115-178lbs is the factory service recommendations for operating range. People normally get higher with a fresh top end.

Share this post


Link to post
Share on other sites

Thanks guys, I got the bike running today after cleaning and re jetting the carb. But that was short lived about 5 mins worth. So I took out the plug it was wet and black and very oily, so I cleaned it off put it back in and fired her up again, exactly the same thing so I did this 4 times each time the same thing, the last time I fired her up I decided to see if the power valve was opening up and it's a no go there, so I think it's a top end rebuild for me or I will do the lot while it's in bits. So thanks guys for all your input.

Share this post


Link to post
Share on other sites

I just had this issue on my 96. I got a new plug and a new header pipe and it fired right up. Make sure the header pipe is sealed. If it is not you are losing all your compression.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×