Should I go back to stock pilot jet? need help
#11
02-03-2018, 06:00 PM
Is my understanding that the engine feels flat when accelerating? But starts ok, if a little rich? Seems like you should get hard acceleration pinned down before looking at idle mixture. Try a test drive with the air box lid removed unless you can read the AFR while riding. I would assume that removal of the lid will lean out the AFR and based on the way it runs adjust your needle position or main jet size. If it runs worse with the lid off then the carb is likely set up lean. Also, fuel economy will reflect AFR correctness as max fuel economy should happen slightly lean from stoichiometric AFR but due to imperfect real combustion in a real engine somewhat rich gets best power. Both significantly rich or lean should return lower economy as both will result in lower adiabatic flame temperatures, hence lower peak cylinder pressure. Excess air, lean, and you are cooling the flame. Excess fuel , rich, and you are cooling the flame. Look up the adiabatic flame temp for gasoline and you will see a chart where the temperature, which equates to pressure also, peaks around 14.7:1. Listen, read, experiment, think, and enjoy the learning process.
#12
02-04-2018, 03:23 AM
update:
after around 5 rides
kept the pilot jet, so running the stage one DJ 116 main with needle and etc...38 pilot and I have the fuel screw around 2.25--2.2 turns out not
its been starting up really good. I can come back after an hour it starts right up. starts up cold
the ride will still be a tiny rough I just have to be skillful with the throttle.
not much has changed ..still need to figure out why its rough
but I think the problem is the low throttle...so maybe its the pilot jet.
I think ill buy a kouba, have the float checked and also tried snapster's test.
after around 5 rides
kept the pilot jet, so running the stage one DJ 116 main with needle and etc...38 pilot and I have the fuel screw around 2.25--2.2 turns out not
its been starting up really good. I can come back after an hour it starts right up. starts up cold
the ride will still be a tiny rough I just have to be skillful with the throttle.
not much has changed ..still need to figure out why its rough
but I think the problem is the low throttle...so maybe its the pilot jet.
I think ill buy a kouba, have the float checked and also tried snapster's test.
#13
02-04-2018, 03:24 AM
what is this?
I usually adjust it with a drill bit ...with the exhaust off ..its still a PITA. or drain and rotate the carb
the drill bit I use is small one for computer / electrical stuff... but compared to this its way smaller and still hard to fit in.. how does this even fit?
I usually adjust it with a drill bit ...with the exhaust off ..its still a PITA. or drain and rotate the carb
the drill bit I use is small one for computer / electrical stuff... but compared to this its way smaller and still hard to fit in.. how does this even fit?
#14
02-04-2018, 03:30 AM
{Quick comment relating to hard starting - Read my post in the hard starting thread. I'm betting the float level is just a bit high. Others may say not, but it certainly is worth trying to slightly lower it. You will not run the bowl dry at full throttle and it will not affect any other jetting. If it is too high it may be part of the issue you are dealing with here, but I don't know.}
Now for this thread
Turning the screw in will lean out the mix, turning it out will make it richer. You do not need a Kouba needle. It is easier to use, but if KLXter will either tell where the picture is (I forget) or put it here again he did a trick adjuster screwdriver deal using one of those hex bits you can get for a buck at a hardware store and I think an O-ring. I'm not near my bike right now, but isn't there enough room to reach in from the left side to do idle mix adjustment while running? To use the idle drop process the bike has to be running to hear/feel when the idle starts dropping. So you do need to reach and adjust the needle some way other than around the pipe on the right side. As I said I can't look at my bike right now to see.
As for anything KLXter writes about Dyno Jet, as I tell my students about their worksheets, READ IT ALL. Take your time read it five times carefully word by word. Don't skim and jump into a bunch of questions. Read it, look at your carb, think about it. It takes time to figure things out. It doesn't happen instantly. It takes time to comprehend this stuff. This is NOT an insult to you. It seems it is human nature to read fast then jump and run. I'm just saying read with care and mentally digest everything you are reading.
I think I went through the Marcelino cam timing modification a dozen times before I felt I understood what was being done and how to do it. Same with your starting problems in the other thread. As I read again and again and thought more and more I think there is a point there for your starting issues. Not sure if it plays into this thread though.
Now for this thread
Turning the screw in will lean out the mix, turning it out will make it richer. You do not need a Kouba needle. It is easier to use, but if KLXter will either tell where the picture is (I forget) or put it here again he did a trick adjuster screwdriver deal using one of those hex bits you can get for a buck at a hardware store and I think an O-ring. I'm not near my bike right now, but isn't there enough room to reach in from the left side to do idle mix adjustment while running? To use the idle drop process the bike has to be running to hear/feel when the idle starts dropping. So you do need to reach and adjust the needle some way other than around the pipe on the right side. As I said I can't look at my bike right now to see.
As for anything KLXter writes about Dyno Jet, as I tell my students about their worksheets, READ IT ALL. Take your time read it five times carefully word by word. Don't skim and jump into a bunch of questions. Read it, look at your carb, think about it. It takes time to figure things out. It doesn't happen instantly. It takes time to comprehend this stuff. This is NOT an insult to you. It seems it is human nature to read fast then jump and run. I'm just saying read with care and mentally digest everything you are reading.
I think I went through the Marcelino cam timing modification a dozen times before I felt I understood what was being done and how to do it. Same with your starting problems in the other thread. As I read again and again and thought more and more I think there is a point there for your starting issues. Not sure if it plays into this thread though.
from the beginning ..I had planned to not buy the kouba b/c I thought id have a fool proof setup...but I guess it didn't work out.
I appreciate all the references and knowledge/advice ...I dont mean to skim over nothing I just haven't been having a lot of time to put into the bike with college and what not.
I always avoid a half *** job... I'm actually considering taking the bike in to a shop just to get some things checked out and talk to a mechanic.
ill make sure read up on the forum resources when I get the time.
theres a possibility its not the carb at all ...maybe piston slap the bike had 20k before I even bought it so I'm not sure how the last guy treated it...and I've put a good ~5k on it so far, its my first bike the clutch could have been messed up... idk
Last edited by horror_fan; 02-04-2018 at 03:33 AM.
#15
02-04-2018, 05:52 AM
My little fuel screw tool fits perfectly.. I use it to set the fuel screw, on a hot running engine, to the midway point between idle drops. It is not fun, but it only has to be done once.. I assume that what you are calling your "drill bit" is not actually a bit for drilling holes with..
#16
02-04-2018, 02:38 PM
Quit doing things like using a drill bit as a screw driver. It may be spinning and the screw not moving.
Go to a hardware store, buy a small flat blade screw tip like that, stick on a scrap of hose or wind a rubber band around it a bazillion times to get something to grip. It's gonna cost you maybe two bucks. Reach in from the left side and adjust it. When you turn the screw in do NOT make it tight, only till it lightly seats, then turn out from there..
I saw idle mix screws with thumb wheel ends on ebay for like $5 some say they fit KLX250.
Go to a hardware store, buy a small flat blade screw tip like that, stick on a scrap of hose or wind a rubber band around it a bazillion times to get something to grip. It's gonna cost you maybe two bucks. Reach in from the left side and adjust it. When you turn the screw in do NOT make it tight, only till it lightly seats, then turn out from there..
I saw idle mix screws with thumb wheel ends on ebay for like $5 some say they fit KLX250.
#17
02-07-2018, 07:54 AM
tried running the bike without the the air box lid... the ride seemed smoother but it ran like crap during anything about 1/4 throttle (as expected, the main is not big enough) ...
I'm going to check the float level this weekend.
I'm going to check the float level this weekend.
#19
02-07-2018, 11:39 PM
above 1/4 throttle it was extremely lean but under that it was normal.
with lid
revs smooth and good at idle (high to low rpms)
rides and revs good riding at higher rpms...shifting fast
sounds like its knocking at lower gears shifting slow with "small throttle" ..(maybe I'm just bad at shifting) ...this is why I think I need a smaller pilot jet maybe the 35 or the float needle
I have to keep adjusting the idle screw too... if I have it set at 1.3-5 rpm it will start good but then it moved up to like 2k rpm ...so ill turn it down ...then the bike won't start cause the idle is too small ....!!!FFFFF
today opened the reserve valve instead of normal fuel and ...I think it was running better... maybe I need a new pet **** too? ...
Last edited by horror_fan; 02-08-2018 at 02:32 AM.
#20
02-08-2018, 12:49 AM
OH, ok.. so finally a good description of an issue - Quote: if I have it set at 1.3-5 rpm it will start good but then move up to like 2k rpm ...so ill turn it down ...then the bike owns start cause the idle is too small ....!!!FFFFF
Is is possible he is adjusting his idle speed with his fuel screw?
How bout setting the Fuel Screw to 2.5 turns out and don't touch it again for any reason - any at all. (Do this carefully with a properly sized slot screw driver..)
Start the bike and once FULLY HOT with CHOKE OFF, set the idle speed screw to 1300- 1350 rpm..
Enjoy..
If that fails to work, you have bigger problems - problems not associated with fuel screws..
Is is possible he is adjusting his idle speed with his fuel screw?
How bout setting the Fuel Screw to 2.5 turns out and don't touch it again for any reason - any at all. (Do this carefully with a properly sized slot screw driver..)
Start the bike and once FULLY HOT with CHOKE OFF, set the idle speed screw to 1300- 1350 rpm..
Enjoy..
If that fails to work, you have bigger problems - problems not associated with fuel screws..