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Is the SM & S carb the same?

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I just bought an 03 S, the previous owner put on a SM carb. Is there a diffrence between the two. He has also dome the 3x3 mod but no rejetting. The bike runs fine, do i need to do any re-jetting. If so what do i need?

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From what I have read here on TT there are some slight differences in the factory tuning of the SM carb and DynoJet sells a specific kit for the SM carb and the SM carb works better with a larger main jet than the S carb. If the 3 X 3 mod is done, it should be rejetted. Post what is in the carb now. Do you intend to install a DJ kit? Someone else can give more reliable jet sizes than I can. I have not worked on a SM.

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Not sure about the DJ kit, what are the pros and cons of the DJ kit? I am expecting to be riding a wide array of altitudes from 300 to 12000 feet. I want whatever will make the bike run the best and most effeciently.

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uh, there is no one jetting setup that will work for that range of altitude. If you are really going to ride between those elevations, you better be prepared to change your jetting often.

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Most of my riding will be done between 300 and 2500 feet, But i plan on doing the trans america trail next spring and know that covers a huge range of altitudes and want the best setup for that.

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Really, I am not the best person to tune a SM carb. But, if it runs good now and you are not looking for performance improvements, it might be best to leave it alone. General advise is to bump the pilot jet from stock 22.5 to 25. The Dyno jet needle is both richer and adjustable with 5 clip positions and the main jet is I think 150 for the SM. If you need to jet for that range of altitude, I would jet for 2500 to 5000. It may be a little rough as in hesitations at lower and it will be rich and boggy at 12000.

The choice between the 22.5 an 25 is how it starts, idles and responds to throttle. If OK now, leave it. Next is needle. Got any flat spots or lean hesitation at 50 mph steady throtte? If OK leave it. Main jet, really need to know where you are at now. S bike comes with a 142.5 and you can go smaller. Not sure what the SM comes with.

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Not sure about the DJ kit, what are the pros and cons of the DJ kit? I am expecting to be riding a wide array of altitudes from 300 to 12000 feet. I want whatever will make the bike run the best and most effeciently.

Just installed an Edelbrock carb. on a DRZ400 and it works great. Simple and externally adjustable.

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Just installed an Edelbrock carb. on a DRZ400 and it works great. Simple and externally adjustable.

Ive heard horror stories on how rich the edelbrock carb can make the bike.....what is your settings?

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It does hesitate a little at constant throttle at around 35 to 45 ish. After 45 its very smooth.

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Considering you are planning to go to higher elevations, if you can live with the hesitations you have now, I would leave the needle as is. Still would be nice to know where you are with the main jet.

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i would open her up and find out what the jetting is.then post this same thread in the jetting forum.if you would be going up high in altitude i would leave it stock but i would change the pilot to a 25 and put in an extended fuel screw so you can make quick adjustments while riding up in elevation

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