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stock drz carb. extended fuel screw help.

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First off, I have an '06 DR-z400S, stock carb. So I'm a little confused. I was told to use an extended fuel screw because they are 'dope' for being so easy to adjust on the fly. Well worth it, right?! Well, Eddie advised me to turn out the screw 3 turns. Okay. Well, some people at the shop said that at 3 turns it won't hold and just fall out. Okay......So will the stock screw do that too? Is this guy full of it? Is the extended fuel screw worth it?

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I ran mine at 3 turns out and i never had a problem with it falling out.

Mike :thumbsup::ride:

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The extended fuel mixture screw is worth it.....when you do the 3x3 airbox mod and install the jetting kit specific for your bike (along with the 25 pilot jet, bought separately as its not in the kit). To install the extended fuel screw (assuming your carb is stock untouched), you have to take the carb off and remove the cover that is over the stock fuel screw. If you're going to go to that much effort, you might as well do the complete jet kit install! The DynoJet kits come with a drill and screw and instructions on how to remove this cover. Here's the S specific instructions:

http://www.dynojet.com/pdf/3109.pdf

People that do the 3x3 and jet kit but use the original 22.5 pilot jet are told to run the mixture screw out about 3.5 turns. This is the max out you can go before vibration could make it wiggle lose. Installing the 25 pilot jet allows you to turn the mixture screw in with most people starting out at 2.5 turns.

The final fine-tuning (after 3x3 and jet kit) is done with the fuel mixture screw to get the best off idle throttle response. For some people, 2.5 turns out works, for others 2.75 works. With the extended screw you can reach down and turn it in say 1/4 turn, ride the bike a few miles, turn it again, test, turn it outwards 1/4 turn past your original setting, test, repeat until you find the setting that seems the smoothest running.

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I have a Yamaha FZ1 streetbike with 4 Mikuni 37mm BSR carbs (similar to the DRZ-S 36mm BSR carb) and I have the factory mixture screws set at ~5.0 turns out as per the jet kit maker (other carb changes were made as well including drilling out the pilot bypass holes, hence the need for mixture screw setting). The screws haven't moved in over 2 years and 25,000+ miles. Now this is on a 4 cyl streetbike rather than a single cylinder thumper, but it gives another point of reference. 3.0 turns out on the stock DRZ-S carb shouldn't be a problem and I seriously doubt that it would ever fall out if the spring, washer, and o-ring is properly installed.

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I have a Yamaha FZ1 streetbike with 4 Mikuni 37mm BSR carbs (similar to the DRZ-S 36mm BSR carb) and I have the factory mixture screws set at ~5.0 turns out as per the jet kit maker (other carb changes were made as well including drilling out the pilot bypass holes, hence the need for mixture screw setting). The screws haven't moved in over 2 years and 25,000+ miles. Now this is on a 4 cyl streetbike rather than a single cylinder thumper, but it gives another point of reference. 3.0 turns out on the stock DRZ-S carb shouldn't be a problem and I seriously doubt that it would ever fall out if the spring, washer, and o-ring is properly installed.

Thanks for your opinion and experience with a bike that is very different then the DRZ.

Taking a Fuel screw out past three turns on a DRZ is setting your self up to have the screw vibrate out. It may not happen on a CBR1000, kx100, 1955 Nomad with a 513 and twin Holley's.. But on DRZ it most likely will... Proven time and time again.

But hey,, It's your bike.... Do what works for you :thumbsup:

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I had the same concern, and simply drilled a very small hole in the head of the extended fuel screw, and used a short length of fine wire to tether the fuel screw. It is still easy to adjust, and will never go anywhere.

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guys that kientech screw is rich . eddie's settings are for the stock screw, many find that starting at 1.5 with the extended is about right with most ending up somewhere between 1.25 and 1.75, with the 25 pilot

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