[Mad Matt]

Along with enrichening the pilots I was thinking that there might be some advantage to lifting the jet needle a shade to start a little further down the taper. Not much maybe .010" or so. Has anyone tried this or have some input? My thinking is that it will improve punch a little when starting from 1/8 to 1/4 throttle.

I'm also a little unsure how to get an objective performance measurement aside from a dyno test. Being an airplane and two-stroke guy I'm thinking about installing some EGT's in the exhaust manifolds and trying to develop a baseline with the stock setup including standard pilot screw adjustment. Then I'll adjust the pilots to where it's running best and compare the temperature difference. From that I should have a starting point for the needle adjustment. Plus if the carbs are synched then the EGT's should be equal so it's a double check.

I know I'm probably crazy for fussing with this but it's damn cold and rainy in MI right now and I'll need someting to occupy me over the winter. Any input is appreciated. Thanks!

Mad Matt

 

[fog]

Ted Williams said, when asked what he thinks about when he's hitting.
"It's better to not think too much, if you don't think too good".

FOG

 

[bobthebiker]

Here's my advice, if it aint broke, dont fix it. though I'd go and take to pullin them baffles out of the mufflers.

 

[Art1989]

Here's my advice get some washers and shim it up, ride it around 20 min and read the plugs if they are black your needles are to high if they are coffee brown your good. I did roughly the same thing on my sons Ninja 250 we dropped the airbox put on pod filters and drilled out the baffles on the exhaust, I ended up raising the needles .030 of an inch before the plugs read right, now the bike has more power and is smooth through the power band. Don't be afraid to experiment if you raise the needles with washers and it doesn't work out you can always pull them out in about 10 mins and be back where you were. If you’re using and after market air filter you can probably go up .010 to .020 and be fine. Go to the Dynojet website and you can down load the jet kit instructions this will give you an idea of where things are if you have never done it before, and Factory Pro has a fantastic carb tuning guide for free works for any jet kit and it will help you learn about how carb jetting works.

 

[Mad Matt]

Thanks Art1989, it's good to hear it worked on an EX-250. Let's see what happens on the 500. I've got .005" shims made up so I can go up in increments until I determine the best setting.

 

[Art1989]

Great, let me know how it goes

 

[ChopperCharles]

With my pod filters I'm only running a single .020" shim on each needle (plus 132 mains). I've shimmed other bikes with only minor airbox/exhaust mods, and almost always fuel mileage has suffered. I've only needed shims where serious airbox mods (ie, removal of airbox) has caused an over-lean condition in the mid rpm range that jetting alone couldn't remove.

Charles.