Author Topic: Getting the jet needle out of the throttle valve?  (Read 27152 times)

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Offline Friar-Tuck

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Re: Getting the jet needle out of the throttle valve?
« Reply #45 on: April 29, 2010, 01:32:46 AM »
 Stang,
  Your Idle is totally personal preference.     You might have to mess with the air screw as the temps start to increase or decrease.  Since the air screw and pilot are always open to all the circuits of your carb, this is a way to fine tune for small elevation,temp,and humidity changes.   once you run out of comfortable adjustment in them it's time to make an adjustment in your main and move these back to a more conservative setting.
  Ok, I got you on the 32:1 premix and finnishing up the 40:1 in the tank or fuel can.   
Once your temps start to stay above 80 during the day  I would change the main (for Summer) and say move to a spring spring fall change for temps of 70 to 80 and if you run winter 60 to 70 or so you might have to Change mains again.
  Got to go to work . I'll be back fri night sat am.
  Tuck\o/   
"The Truth Has No Agenda"

Offline bigbellybob

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Re: Getting the jet needle out of the throttle valve?
« Reply #46 on: April 29, 2010, 07:20:17 AM »
Quote
I know it was not completely hot yet
there is no point in puling the plug if you didn't get the bike to full temp and do a proper plug chop. the reading is worthless. get the bike to full temp then go WFO for 100 feet or more then hit the kill switch at the same back off the throttle. get your main jet set to give a good reading when WFO and then we can work on the other jetting ranges. until you get the main jetted right its almost pointless to play with the other jetting parameters.
IF RIDING IS OUTLAWED ONLY OUTLAWS WILL RIDE

IF RIDING IS OUTLAWED ONLY OUTLAWS WILL RIDE

IF RIDING IS OUTLAWED ONLY OUTLAWS WILL RIDE

IF RIDING IS OUTLAWED ONLY OUTLAWS WILL RIDE

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Offline mustangfury

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Re: Getting the jet needle out of the throttle valve?
« Reply #47 on: April 29, 2010, 11:44:29 PM »
I took it to the farm yesterday and got her nice and hot. The bike runs a whole lot better. it has an incredible boost in power.  After getting it up to full operating temperatures, I checked the plug and it seemed to be pretty much the same as when i had it around the yard but the electrode was brown and dry looking. the threads still had the same amount of oil on them.  I took her wide open for about 15-20 seconds in first gear and killed it and pulled the clutch in. i looked at the plug and it looked the same as at slower speeds but maybe with a little more of a dry brown area, not much at all though.  I rode her for a while with my girlfriend, about 1-2 hours, and she still developed a coating of oil on the back fender and the inside of the silencer nose was coated as well.  I think it might be running just a tad bit rich still.  When going about 0 to 1/4 throttle if i nailed the throttle to full it would delay a second or two before taking off.  The weather was about 70 degrees with 30% humidity.
1993 KX 125

Offline Hillclimb#42

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Re: Getting the jet needle out of the throttle valve?
« Reply #48 on: April 29, 2010, 11:59:12 PM »
 I just replaced packing on a silencer on a ktm 105. I had just done it this time last year. The front half was totally saturated and the back half, still basically new. You want the dry brown, and the noticeable increase in power. Getting the jetting right, really helps power. You probably are just dealing with lots of oil in the packing. Its harmless, but changing out the packing will cure it, and will also help your bike, Be careful leaning it out too much. I always start a bit rich, then lean it out only to the point it runs cleanly. Silencer packing is just part of the fun. :-D

Offline mustangfury

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Re: Getting the jet needle out of the throttle valve?
« Reply #49 on: April 30, 2010, 03:11:06 AM »
I just repacked it before i put the new jet in.  Yes it is a lot more fun and yes start rich.  I was actually thinking of finding where it runs perfectly clean, then drop back one jet just to reduce wear.  Thanks for the tips.
1993 KX 125

Offline mustangfury

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Re: Getting the jet needle out of the throttle valve?
« Reply #50 on: April 30, 2010, 03:37:05 AM »
I went ahead and ordered some more jets because the ones i originally got were all richer than the one currently in there.  I'm not changing anything yet, but i want to have them on hand.  Also, i figured since when in the summer, the engine needs less fuel, i will more than likely need a jet leaner than the one i currently have.  I got a leaner pilot screw as well in case i need it: it was cheap.  For mains i ordered: 155, 152, 150, 148; for pilot: 50.

Just letting you know what i have to work with.  Thanks
1993 KX 125

Offline Friar-Tuck

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Re: Getting the jet needle out of the throttle valve?
« Reply #51 on: April 30, 2010, 08:52:52 AM »
Oky Doke Stang,
  You're working in the right direction!   Riding around at low throttle and then whacking the throttle open you're experiencing  what is called "loading up"  or still just too rich.   
    If riding around at low throttle you just have to "Clean it out" once in a while until you get comfy with where you go with the main.   I was hoping you would see a difference in the power so you wouldn't feel you were wasting your time and money.    Your riding style is going to come into play the more as you get closer to what you feel is dialed in.
  plonking around with a slower rider, or holding the bike at or near full throttle could be the difference of two or three main sizes.   If some one else took your bike and went racing they might stay right where you are for your weather conditions.
   Another guy riding single track chasing his kids may go leaner, there are so many variables its hard to just tell somebody what is gonna work for them or not sight unseen.
   Please be careful from here on out. I have never had a bike seize moving one jet size.  After the big jump from 170 to 158,  move one at a time and keep a record of where you're at and the conditions.   You can see the difference in your electrode now as far as dry and oil fouled/oily.    It might take a bit more to get your exhaust cleaned out.
  Hang in there!
Once you get to a place where your happy you will only have to make small adjustments
during regular maintenance between rides.
   Tuck\o/   
"The Truth Has No Agenda"

Offline mustangfury

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Re: Getting the jet needle out of the throttle valve?
« Reply #52 on: April 30, 2010, 09:50:37 AM »
thanks for all the help.  I was planning on going down one step at a time with the main and i plan to stop when i see there are no more oil deposits on the electrode or when it just flat out performs the way i want it to.  If i go till i see no more oil and the performance isn't really better than the last, i think i will go back up one size just to limit wear.

I kept cleaning up the oil that was forming on the rear fender and by the end of the day it seemed as if it was spitting more than at the beginning, so i think it started getting more added to it, plus the plug still had a little oil on the threads.

My riding style i figured would call for a leaner setting simply because i never really give it full throttle except for short runs through a field here and there.  I usually run at between 1/2 and 3/4 throttle. I like doing slow maneuvering type of stuff.  Drifting around turns and riding through the woods and short jumps and stuff.  I rarely even get past 3rd gear most of the time.

thanks again.  I'll keep you posted how things go.  I really appreciate the time you've put into this for me.
1993 KX 125

Offline Friar-Tuck

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Re: Getting the jet needle out of the throttle valve?
« Reply #53 on: April 30, 2010, 07:04:54 PM »
     Folks took time out to help me so no worries.
 I do wish I had a better ability to lay things out in easy to understand terms and or examples.  However with a little research I think you got the jist of it.  There really is no special secret to getting a bike dialed in. Just some patience.
  Tuck\o/
   
"The Truth Has No Agenda"

Offline mustangfury

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Re: Getting the jet needle out of the throttle valve?
« Reply #54 on: May 01, 2010, 12:30:25 AM »
I think you did a great job of explaining things.  I had the idea of how to jet it in.  I just wanted some guidence from someone who had done it before. If i had just done it myself, i would have never made a big jump from a 170 main to a 158.  I would have just gone one at a time and without having done something before, there is always the thought of "am i definitely doing this right?"  having someone who has done it before telling you what to look for avoids that question.

thanks
1993 KX 125

Offline mustangfury

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Re: Getting the jet needle out of the throttle valve?
« Reply #55 on: May 09, 2010, 01:49:08 AM »
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
1993 KX 125

Offline mustangfury

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Re: Getting the jet needle out of the throttle valve?
« Reply #56 on: May 09, 2010, 09:55:35 AM »
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.


1993 KX 125

Offline mustangfury

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Re: Getting the jet needle out of the throttle valve?
« Reply #57 on: May 09, 2010, 09:59:23 AM »
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
« Last Edit: May 09, 2010, 10:11:29 AM by mustangfury »
1993 KX 125

Offline Friar-Tuck

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Re: Getting the jet needle out of the throttle valve?
« Reply #58 on: May 10, 2010, 05:40:09 AM »
 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/

 
"The Truth Has No Agenda"

Offline mustangfury

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Re: Getting the jet needle out of the throttle valve?
« Reply #59 on: May 10, 2010, 07:33:13 AM »
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.
« Last Edit: May 10, 2010, 09:07:54 AM by mustangfury »
1993 KX 125