CV Slide modifications

Disclaimer: This in NOT REVERSABLE, I had spare slides in case I ruined these. New slides from Yamaha cost more than you paid for your bike. I'm pleased with my results but make no claims that it will improve yours.

I noticed that my '77 CV carbs had what looked like a cutaway on the bottom of the slides and I wondered why the slides from my '80 carbs did not. It seems to me that the shape of the slide would affect the air turbulence in the carb just as it does in the intake port and you certainly don't want sharp edges in your intake port.

So I started by making sure I had plenty of spare slides (I love to buy junk carbs) and got out a coarse file. I cut a small bevel about 7mm in and 4mm deep and smoothed it out with wet/dry sandpaper. This felt like a big improvement. Notice that I also enlarged the hole that allows the lower venturi pressure to draw the slide upward. I did NOT enlarge it as much as DynoJet kits do but did enlarge it slightly. This felt like a significant improvement but I'm not one to leave well enough alone so I decided to go for even more.

The picture below is the next step I took and is how I am running my slides now. I have an XS1100 like this and an XS650. Both showed the same improvement in smoother power right from the moment you crack the throttle. I used a vibrator sander and progressed thru 180-600 paper to round and polish the surface after filing to rough shape.

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