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View Full Version : Should I go back to stock jets and needle positions?


ontarioyamaha
02-25-2008, 06:10 AM
I have been riding a 1995 Vmax 600 this winter. I have put on about 500 k and have been having an issue. It runs great from 0 to 4900 rpm and again from 5900 an up. It makes a burling sound not really a popping sound that would be indicative of running lean.

I held it at 5500 rpm and let it burble. I then hit the kill switch and pulled the plugs. They were very fouled and black with deposits.

I figured it would be better to richen it up just in case it was running lean (plugs are cheaper than pistons) I pulled the slides and found that the clips were on the top groove. I lowered them back down to the center (standard position) and went for a spin. It was much worse and ran like hell.

Before I put it back together I checked the main jets. They are 155.3 and the stock jet is 156.3.

What do you think I should do? I have 2 scenarios; 1, change the position of the needle back to stock and change the jet back to stock and start from here or 2, install a 154.3 jet and try to lean it out a bit more. It does appear to be running rich. I am fairly confident that it the issue.

I am at a crossroads and I would love some input……..
JAMIE
02-25-2008, 08:22 AM
did you notice if the plastic shim was still underneith the clip,you could always remove that as well but maybe check the number on the needles and see if they correspond with the ones in the manual.If that checks out to be o.k. and you got the correct needles check your reeds to make sure they are not all chipped.Let me know.
ontarioyamaha
02-25-2008, 09:39 AM
I did not check the needle number but the shims were both sitting on top. The needle position is in the leanest position.
AL P
02-25-2008, 10:02 AM
other then "air" obviously entering into the fuel/air mix VIA the carbs throat...have you made sure the one (or two, not sure on your exact carbs?)
anyway, on the intake/air box side of the your carb/s, and at the bottom of the carbs throat, are one or two very small inlets..there for mixing air into your main/pilot air/fuel ratio..are they for sure clean, with no restrction due to debri ect??

Here`s a pic of what I`m talking about..although these are carbs off a totaly differant motor..they show what I`m refering to, which is the same basic inlets that a vmax4 has, and I`m asumming a 600 also?
http://img179.imageshack.us/img179/1496/airinletsdb3.jpg