my own kx 60 problem

[madness]

well bought this bike awhile back. had the top end done when he did it they he said they made some mods to the intake but not the exhaust ports. had the carb cleaned and rejetted. problem is that when you ride it. it runs crappy cuts out and Excellerates very poorley. the bottom ends has been pretty much replaced minus the crank. i have had it to 2 different motorcycly shops. when i get it. it starts right up. but then goes back to the same thing. so the only thing i can come up with is the mods to being done to just the intake side and not the exhaust. the reeds have been replaced but still stock. the spark plug is fine. the timing has not been changed. any ideas. i have changed the muffler packing thats fine. the air filter i keep clean.   

[Magnus]

If you did not tell them to make any modification then they shouldnt do it. I would ask them what they did, and if they did a bad port job then IMO they owe you a new cylinder

Could of course be something else but seems likely that they made a mistake..

I am not a fan of doing to much to standard porting on anything, and if done it should be done by someone with experience.. if it is the mod that is the problem then you could take it to someone who does porting to se if they can "save" it by doing a complete port job..

have you checked the timing with a strobe light? and what change did you do to the jetting? 

[madness]

no i havnt checked the timing with the strobe light. when they did the carb the first time they went down a jet. then when i took it to the dealer they took it back to where it was before the carb jets where messed with. how about the reeds he said they put new ones in but just looking at different things. well i have a spare jug i guess thats what you call it but i am going to send it to eric gore and have him redo the old one put new pistons and rings. just thought i would check and ask some questions before i went that far. seems odd to me that you would do something to the intake side and not the exhaust side.

[madness]

if the timing has to be changed do you have to have the piston at top dead center

[Magnus]

I dont know what the timing should be on the kx60, but check that the flywheel has not moved on the crankshaft ( in rare cases the flywheel key can brake). The cdi often have a built in advance/retard function on most modern bikes, and I have seen cdi boxes lock in a full advanced or retarded state.

If you use a strobe light on the timing marks on the flywheel and stator, you should see that the marks align at some rpms and move away at other rpms. If you have the manual, it probably will list the timing advance in degrees at a certain rpm. 

[mx_dad]

i suggest back to the basics. Verify all electrical connections to CDI and coil, are clean and tight (di-electric grease is always a good thing). You mention the plug is "fine", but what does that mean? Did you do a plug chop test to determine the plug is fine?

• Does it idle when warm?
• Are you losing any gear oil (or is the silencer filling with oil? Verify no wet side crank seal leak)
• Does it cut out when just revving in neutral, or when under load?
• Plug chop test results, idle, mid-throttle, full throttle (remember to kill the engine before returning to idle, or driving back for mid and full throttle test)
• Did you try a new plug to eliminate a high voltage failure on the plug/and wire? Remember checking spark outside the engine is a different atmosphere than in a combustion chamber. It's worth checking, but always reserve the possibility that the ignition system can fail with a plug in a combustion chamber yet look fine in the normal atmosphere.

Trying to eliminate the things other than the obvious, which would be a botched porting job. I would just put the other cylinder on and give it a shot. Let us know what you find out.

[madness]

1. had the motor rebuilt and the cab rejetting twice. the motor bogs idles fine and revs fine. it bogs once you get going and gets worse as time goes on to the point where you cant kick start or push start it. i do know that if you leave for awhile and come back and the gas isnt turned off it gets flooded to point that i can barely push start it. if it sits for awhile then it will start. after the motor was rebuilt the mechanic forgot the key and the flywheel bolt came off.

2. he said when he did the motor rebuild that he modded the intake exhaust to give more bit and advanced the timing. it has a bills pipe stock exhaust. i did put it back to stock timing but that didnt change anything. the piston still looks nice and shiny and havnt found anything wrong with it on that end. it does have stock reeds in it.

the only thing i can think of is one being that the jets where replaced i am wondering if the floats are not level. possible the timing maybe off and i will be checking the electronic connections and look again at the point where you check the timing. i use NGK Iridium maybe thats the problem. any other ideas or comments. i have spent about 1300 in this dirtbike and going t get it running by hell or high water.

what are the symptoms if there is leak in the motor as far as pressure testing goes

the other thing i was curious about is that when i actually do get it running it appears like there is water in the oil is appears to look like a milky substance but after it sits it goes back to looking like regular oil. is it just crappy oil that films up bad. i am sure there not using that great of oil when they fixed the water bearing seals.

[Friar-Tuck]

Hey mad,
 Chris has had a heck of a time getting his 60 to run correctly and seems to have the same description of how his bike
  Runs.  With no air screw to help dial in the carb you only have the clip position and needle to assist in the acceleration.   I cleaned up the casting flaws in his ports and matched the sizes, with a 1mm or so opening up of the exhaust.   I got the dimensions for the ports from Eric Gorr so it was not like I just made them up. 
  Chris said his bike will run well opened up in 6th but 1-5 is lacking power. I suggested he lower his clip
(raising the needle richening up the bottom end) 
 
 if your bike is flooding the needle and seat of the float is probably leaking.  The next time you have the carb apart remove the needle seat from the carb body and check to see that the o-ring has not become cracked or hardened as well as the seat be clean.  The needle and seat are around $13.00 from Jets-r-us  it should also be avail. from your dealer.
   If the needle and seat are infact leaking it will play havoc with your jetting as the bike will continually be flooding.
  Tuck\o/

[chris-mets]

yessir

[madness]

well did discover that someone bent the float height so i am playing with that but i do believe thats the problem when i took out the reeds you could see alot of gas sitting there by the piston and it has been sitting for abit.  thanks for the input