Thread: Ssr xf250
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Old 05-06-2017, 12:23 AM   #34
2LZ   2LZ is offline
 
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Join Date: Mar 2010
Location: Volcano, Ca
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Throttle Response

Though CV carbs have a throttle plate like a car, they rely on vacuum to draw up the slide. When in proper balance, they work very well and meter the fuel excellently.

That said, most are also set up for EPA and CARB requirements. Due to them not wanting an immediate rush of fuel when you open the throttle which will create more unburnt fuel, this is what causes the slight lag in throttle response.

If you have the same style carb, see in the pic, there's a small plate held in by Phillips screws behind the choke lever. Remove that plate and block the tiny port with a small amount of fuel resistant RTV silicone. Then remount the plate after it sets. This will improve throttle response as it did on Q.
Also, you will find the idle mixture screw on the top looking straight down on this carb. I set mine at 2 turns out and adjusted from there. You will find with the OHC motor, it is more hungry and you will find you'll need to run fatter jets than the Hondoids. The other beautiful thing about the CV carb is changing jets. Just loosen both clamps, undo the throttle cables and spin it. You can remove the float bowl without removing it from the engine. It will make testing jetting a breeze.

The "EGR" that you are referring to is actually an air injection. It does not hamper performance, but once you remove the cat, it will toss that extra cool O2 (at heavy throttle) that was supposed to burn unburnt gas off your cat and throw it on your muffler packing. If you are not removing the cat, I'd sugget leaving it functioning to keep your cat free of buildup. If you wish to remove your air injection, along with your cat, make a plate and block the head and plug the vacuum port, great. What I did with Q was I plugged the fat rubber hose (with a fat bolt with the head cut off) and plugged the vacuum feed with a BB. 5 minute fix.
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Last edited by 2LZ; 05-26-2020 at 12:24 PM.
 
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