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Old 10-16-2014, 05:54 PM   #1
tommer2 OP
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36mm Mikuni help on 75 Honda XL350

I need some help. I'm having trouble with my stock XL 350 with a 36mm a Mikuni. I can't get it to idle. Runs great and pulls hard from quarter throttle up. Has a Torque Engineering pipe on it. Completely cleaned and blew out all passages in the carb. Here's my jetting. 2 air jet, 20 pilot, 159 P5 needle, 6f8 jet needle, 220 main. Clip in second from the top. Timing is spot on. Right between the two advance marks at 3-4 thou RPM. Checked it many times!!! New points and condenser. Gapped at 13-14. New plug D8ea gapped 24-25. Good blue spark. Fresh gas. Seems to load up then dies. Does better without the K&N air cleaner on it but not much better. Let's hear it!! Thanks

tommer2 screwed with this post 10-16-2014 at 06:02 PM
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Old 10-16-2014, 06:42 PM   #2
Cogswell
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Sounds your pilot circuit is too rich. What model carb ? Fuel or air screw to control pilot circuit. Turn fuel screw in or air screw out, probably at least half to a whole turn to start with. That should get you started in the right direction.


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Old 10-16-2014, 06:50 PM   #3
tommer2 OP
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It's a 36mm Mikuni VM round slide. Air screw. Yea I thought the same thing on the rich pilot. 20 pilot sounds little! I will say this, it really doesn't do much when I turn it to the left to add more air.
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Old 10-16-2014, 09:59 PM   #4
redprimo
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I've always had better luck static timing to the F mark and verifying with a light that the advance is correct. I've gotten burned by relying on dynamic timing on a bike with bad springs on the advancer.
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Old 10-17-2014, 07:22 AM   #5
tommer2 OP
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Yea, Thanks for the thought. I agree. That's what I did. Static at the F mark. Timing light to the full advance marks at 3-4 thou RPM.
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Old 10-17-2014, 02:32 PM   #6
redprimo
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How did you set the air screw? It's such a forgiving carburetor it should run with just about any jets, getting top performance can require some fiddling, but just getting it to idle sounds like it's the air screw or a clogged passag..
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Old 10-17-2014, 04:41 PM   #7
JeffS77
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Try with no air jet ?

What # is the slide cutaway ?


Scroll down this page might give you some ideas of things to try

http://www.oldrice.com/CarbStuff.htm
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Old 10-17-2014, 06:33 PM   #8
tommer2 OP
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The cut away on the slide is a 2.5. I thought about removing the #2 air jet. Does it screw out of one of the holes on the air cleaner side? I've cleaned this sucker 2-3 times. Thought I had it cleaned. Will check again. Like I said I have a 20 pilot jet in it and that sounds small for a 36mm. The air screw still doesn't do anything when I try to lean it out. Maybe it is still partially clogged?
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Old 10-17-2014, 09:27 PM   #9
JeffS77
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Air jet located here..take it out see if it helps




FYI anytime I have ran a VM on a four stroke I always have had to run them rich on the idle circuit to get them to run right just off idle. Sometimes they don't like idling very well but I only ever use em in race applications so not that big of a deal just got to blip the throttle every once in awhile. I have also seen jetting specs on complete opposite ends of the spectrum listed for exactly same bikes but there is so much in play that can change that drastically.

It took me a long time to get a VM dialed in on my '79 KLX 250 ( 4 stroke 2 valve motor) but she is a screamer now. I fought the just of idle bog and or sputter for a long time. I lucked out and scored a box of every jet size imagine able for $10 at a swapmeet...it helped a lot and had lots of needles and needle jets just sitting around.

My 250 is about 25-30 idle and 180 main, sorry can't remember the rest of the specs. I do know it has the 2 stroke style needle jet and not the 4 stroke style. But I have seen people use both on 4 strokes.
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Old 10-18-2014, 09:02 AM   #10
tommer2 OP
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Good info man!!!! Thanks
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Old Today, 05:11 PM   #11
tommer2 OP
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Removed the air jet and put in a 30 pilot jet. Now it runs and idles great!! Thanks for the help.
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