Maintenance & Technical > KX250 / KX125
Getting the jet needle out of the throttle valve?
mustangfury:
Ok, i just tried the 155 main jet and i noticed a difference with the spark plug.
Jumping to the 158 from the 170, i rode it for about 15 seconds wide open and killed the engine and pulled in the clutch. The electrode and the insulator were both a dark brown but not oily. The first three to five threads were oily though.
I put in the 155 main and rode it for about 10-15 seconds wide open and killed the engine immediately and pulled in the clutch again. The insulator was the same dark brown, but the electrode faded from dark brown near the threads to a whitish brown near the tip. The first three threads were again a little shimmery with oil.
As far as oil out the back, after riding for about an hour the rear fender was again pretty soaked with oil. It was dripping pretty good. When you nail the throttle wide open a puff of blue smoke comes out the exhaust. My guess is that maybe it is from lower end jetting being too rich. So, you're riding around at mid range and all that oil is accumulating, then you nail the gas and it coughs up a blob of that oil that accumulated. Is my logic sound?
I am more than satisfied with the top end power from both the 158 and 155 jets. The 155 was responsive all through the powerband. The 158 was a little sluggish sometimes at lower throttle ranges. I am still not satisfied with the mess that i have to clean up after i ride though. Is this a problem where i still need to go leaner than the 155,should I stay with the 155, should i go back to the 158, and is the oil spitting now just a problem with the lower range jetting?
I have pictures of the plug on my dad's phone i will try to see if i can transfer them to the computer and uploaded them asap.
Thanks
mustangfury:
ok here are the pics from my dads phone. These are the pics of the plug right after riding wide open for 10-15 seconds with the 155 main jet.
mustangfury:
These pics are the pics of the oil it is still putting out after a 1-2 hour ride. Remember i repacked the silencer before this ride.
can you add pictures to a previous post? The only way i was able to add the others was by making a new one. Sorry, for so many posts in a row.
thanks
Friar-Tuck:
Stang,
Your right on about the bike "loading up" with oil while trail riding 1/4 ~ 3/4 throttle and then "Cleaning it out"
with a wide open run.
The oil & unburnt fuel collect and then get blasted out when you open her up.
I wouldn't go any leaner on your main just yet. You can clean up the bottom and midrange by raising the clip position on your needle,(lowering the needle in the seat leaning out the fuel/air ratio) and or a smaller pilot, or both.
I wouldn't go any leaner on your main just yet. Get your mid range dialed in a little closer and then have a look at the main again.
The only reason I say that is that the circuits do all overlap at some point, and the pilot circuit is always open.
So leaning out the pilot some more is gonna affect the main to some degree (although it may be a small amount)
And the same goes for the needle, The ankle bone connected to the shin bone kind of thing.
Make your next adjustment, run the bike through the gears and get it up to normal operating temp.
Adjust your air screw for the best throttle response you can get and ride!
I copied this plug chop test description from
"Spankys Jetting Guide"
" The easiest way to test it is to do a throttle-chop test. With the bike fully warmed up, find a long straight, and install a fresh plug. Start the engine, and do a full-throttle run down the straight, through all gears. As soon as the bike tops out, pull the clutch in, and kill the engine, coasting to a stop. Remove the plug, and look deep down inside the threads, at the base of the insulator. If it is white or gray, the main is too lean. If it is dark brown or black, the main is too rich. The correct color is a medium-dark mocha brown or tan. "
You still have a few other adjustments you can tinker with after you feel your bike is running as good as possible with what you have to work with now.
You can still change the throttle slide and different needle tapers. Now those are not cheap by any means, but I guess the point is there is still alot more tuning available to you should you choose to.
There should be less and less oil on your fender and the pipe joints as you continue tuning the carb and the Bikes performance should be getting noticeably better.
Keep tabs on your water and tranny fluid levels as they can also give you a fit if the seals start leaking.
You will soon be able to tell what the bike is telling you it needs by how it's running.
You are making progress Stang, Maybe not as fast as you would like , but hang in there!
Tuck\o/
mustangfury:
should i adjust the clip position first, then if that does not work go to the pilot/slow Jet. Before, when i had the 170 main in, i had to move the clip richer to get the bike to perform better at mid range. It was not getting enough fuel. I figured this out because the bike had better response in the mid range when i put the choke on. After making the main jet 155, i would think that moving the clip back to lean would just cause the same problem. I can still start with the clip to do a double check though, it isn't that hard.
Another question: When i store my bike, does it help make the shocks last if i put it on a stand so the wheels are off the ground? I heard this from someone and was wondering if it was true.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version