needle shim washer thickness

[salamander]

This is probably a "no duh" to the veterans, but for me, a newcomer trying for the first time to fine tune the carbs after rejetting, it was a real nice thing to find.

It would seem that not all #4 washers are created equal.  After rejetting, I had set everything up going straight off of the rejetting table, including using 1 steel shim washer on the needles.  The bike seemed flat on test rides, so I tried adding another washer just to see what would happen, and I was amazed at the difference it made.  Even so, I think a little less than that one additional washer would be better so I went looking for something thinner, like maybe a #3.  Poking around in the hardware store, I found brass #4's.  They're the same size as the steel, but only ~75% the thickness.  I have stock needles with only the single c-clip position, so having both types of washers gives a lot more freedom in adjusting the needle height.

What I don't know yet, and probably won't for a long while, is whether having brass in contact with steel will cause a reaction.  My gut feeling is that there should be no problem, but I can't say for sure.

[mitch79]

I have Australian delivered '06 GS500 with adjustable needles from the factory. When I was tuning my bike I made some measurements.
Each "E" clip position moves the needle up or down 1mm.
There are two washers on the needle, one below the clip is 1mm thick, one above the clip is 0.5mm thick. By moving the position of the washers as well as the clip it is possible to adjust the needle hight in 0.5mm increments.

[twinrat]

when i was fine tuning my gs500f i found that a .5 mm shim on the needle  made no discernable difference in performance .just stick with the 1.0mm washers .

[salamander]

You may be right about the slight difference in shim height not really making a difference in actual riding performance, but I'm still at the stage of trying to adjust rich/lean.  Since one additional "full-thickness" washer made such a difference, it seems to me an intermediate height from using a "thin" washer could be useful.

[jestercinti]

I used 1 #3 washer for a few thousand miles, and did not notice any difference.  Ended up taking it out.

[salamander]

Are we talking about the same thing -- performance while riding vs. richness in the range where the needle height comes into play?