kx65 help

[ozspode]

I have just bought a 2002 kx65 for my son. The bike is in very good condition, but bogs down at about 1/4 throttle or when he rides up the face of a jump.
Could anyone please tell me where I should start looking to cure the problem. Fuel also drains out the overflow tubes.
Any help appreciated.

 

[Luft]

You might take the carb apart and remove all the jets and clean the parts. The float level may not be correct as fuel drains from the overflow tubes. The bog at 1/4 throttle could be from the needle clip in the wrong position. The standard postion is in the middle. If the clip has been raised to lower the needle then that may cause the bog. The carb on this bike is very sensitive to adjustment. I found the stock setting worked best for the stock engine.

 

[ozspode]

Luft
Thankyou for your reply. Could anyone explain the correct procedure for setting the float level.

 

[Luft]

The standard float height is 21.1 +/- 1 mm. Turn the carb upside down and view the float on the idle screw side. The distance is measured from the highest point on the float to the mating surface on the carb. Bend the tang on the float arm to adjust the height. Increasing the float height lowers the fuel level. The stock settings for the U.S. are Pilot #25, Needle clip position #3, Main jet #190. Airscrew 1-1/2 turns out.

 

[Jasle]

Luft is correct on the setting of the float level but if the bog is at 1/4 throttle that usually means you are lean on the pilot jet. the kx has the air screw on the intake side of the carb so turning the screw in lessens the air to the pilot circuit. try turnin the screw in 1/4 turn at a time and see how the bike reacts. Also make sure your filter is clean and oiled before an adjustments.
For the fuel overflowing the bowl do adjust the float level and this should cure this. If it doesn not then look at the float needle and see if the tip is damaged. It could be allowing fuel to flow in to the carb despite the correct float setting. I have seen this many times on bikes that have sat a long time.

 

[Jeff Gilbert]

Jasle, do the KX60 & 65 use the same carb? My daughter's 60 bogs pretty easily and I've yet to see the air screw. She really has to keep the rev's up or it's all over.

 

[Jasle]

I'm not sure if its the same carb but the basics still apply. I know it has either a fuel or air screw. its the pretty small one close to the idle thumbscrew. I've seen some of them capped so you cannot adjust them but thats pretty much on street bikes. If the screw is on the right or air filter side its an air screw. if its on the left or engine side its a fuel screw. You'll probably want more fuel so by turning in an air screw you get more fuel or turning out a fuel screw you get more.
The kx60 and 65 are pretty much top end bikes but you could have issues. If it bogs in nuetral then for sure you need to adjust the carb. If it only bogs under load then maybe reeds. Check to see if they close all the way. You can also get a new reed setup from berg racing that really helps the bottom end.

 

[kxdad]

My sons have had both 60's and 65's, we had to richen the pilot jet by one in each bike, this should eliminate the bogging at 1/4 throttle.
Makes them a little easier to ride too, without the bog and then big hit of power

 

[MX-727]

I had to richen the pilot on my daughter's KX65 even though we are at 4000 feet. Really helped get rid of the bog.

 

[GREENBUNCH]

my daugters 2000 kx60 has the dreaded bog ALSO. I can't seem to find an air screew on the carb so I may have to opt for a pilot jet change. Anybody know what size works best at sea level and who sells the pilots. She loves the bike except this bog stalls the engine when its lugged at 1/4 throttle and then cracked open. Once you get past the 1/4 to half throttle the thing really screams.
Greenbunch

 

[Jeff Gilbert]

Check compression. Hers was down to 145 so I did a topend and it helped a lot.

 

[shane001]

My sons kx 65 was down to 120 in compresion i put new piston and rings and gaskets and comprestion only went up to 135, did i do something wrong????

 

[Jasle]

I usually see 135-160 on a new topend on the 50's and 60's