That's a sign of a lean condition in the pilot circuit.
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Oil & fuel coming out of air filter
- Thread starter marineviper
- Start date
That's a sign of a lean condition in the pilot circuit.
Stating the obvious: new does not guarantee good.
When the idle hangs, that is typically an indication of a lean idle mixture. Dirt in the carbs, worn throttle shaft seals, bad o-rings on the pilot screws, leaks on the carb mounts, or even tight valve adjustment.
When the idle hangs, that is typically an indication of a lean idle mixture. Dirt in the carbs, worn throttle shaft seals, bad o-rings on the pilot screws, leaks on the carb mounts, or even tight valve adjustment.
Chris, I fought the same symptoms with mine when I was way too rich. When the throttle was opened an excess amount of fuel was coming out of the main jet passage and literally pooling in the venturi. The hanging at around 3,000 rpms was due to the excess fuel in the carb (just like "choking" or enrichening). It would take a few seconds for the fuel to burn off and the idle would return to normal. I did the same thing and kept bumping the pilot and main jets to no avail. The problem was finally solved by backing way off and leaning the bike out.
marineviper
XS400 Member
are you talking about leaning out the idle mixture screw??
Agree also. So what pilot jets do you have and where are your idle mix screws set at would be my next question.
Tombo
XS400 Addict
Lots of good people on here helping you out, but as others have stated, the fact that your bike won't pull past 6.5K under load is a tuning issue. These bikes (sohc) (with stock gearing should pull all the way to red in 6th, which is about 88 mph. Have you pulled the plugs? Sounds rich, plugs will tell you.
Also, does it pull strong up to 6.5K? If it pulls strong and then plateaus it could be wrong Mains, or clogged passage for Mains
Also, what kind of exhaust and intake? With that big of jets, it would indicate that you are too rich for stock, or perhaps in the right jet range for unrestricted exhaust and/or unrestricted air filter and intake
Also, does it pull strong up to 6.5K? If it pulls strong and then plateaus it could be wrong Mains, or clogged passage for Mains
Also, what kind of exhaust and intake? With that big of jets, it would indicate that you are too rich for stock, or perhaps in the right jet range for unrestricted exhaust and/or unrestricted air filter and intake
marineviper
XS400 Member
I'm done with the bike the rest of the day and don't know the pilot, but when cleaning the carbs, I had one carb that was missing the rubber plug on the pilot, and the other one had a very loose plug so i took it out.
the idle mixtures screws are out 4.25 on left and 4 on right., i adjusted by removing the opposite spark plug boot and adjusting to best idle
the idle mixtures screws are out 4.25 on left and 4 on right., i adjusted by removing the opposite spark plug boot and adjusting to best idle
marineviper
XS400 Member
And damn, i answered my own question.....ordering a set of plugs from mikexs, holy cow on the shipping.
Tombo
XS400 Addict
I do believe you need those rubber plugs. Also, if I recall correctly, 4 turns out is maximum in needle mixture
marineviper
XS400 Member
Okay, rubber plugs installed, holy 15$ shipping for 5 dollar plugs, but could not find them anywhere else on the internet but mikexs. The bike pulls hard all the way through the throttle, idle mixture screws are now set to 3 1/8 on both carbs and it starts first crank.
The only thing I have found is after riding around it likes to set at 2k when clutching at a stop sign, just letting the clutch out a hair will bring it back down to 1.2k
The only thing I have found is after riding around it likes to set at 2k when clutching at a stop sign, just letting the clutch out a hair will bring it back down to 1.2k
Clutch drag is dropping the revs when you do that.
Tuning the idle can be a bit of a pain.
You want to synch the carbs of course.
Adjust each idle screw independently for the lowest stable idle.
Try turning the idle speed down as well.
Do all your tuning and adjustment when the bike is fully warmed up. If you tune for idle while the bike is cold it's going to idle best when its cold.
Tuning the idle can be a bit of a pain.
You want to synch the carbs of course.
Adjust each idle screw independently for the lowest stable idle.
Try turning the idle speed down as well.
Do all your tuning and adjustment when the bike is fully warmed up. If you tune for idle while the bike is cold it's going to idle best when its cold.
Tombo
XS400 Addict
What bcware said.
precisely that yes 
My rubber plugs over the mains were shot,I made my own out of some plastic caps I had laying around.Mikexs has a good variety of parts but agree their shipping prices are pretty ridiculous.If I order from them I order in bulk.