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Used FCR

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I have a 2000 DRZ400S. So far I have opened up the airbox, changed to a FMF high flow header, changed to a Yoshimura CDI and got a used Keihin FCR 39mm carb. off ebay.

I have read the sticky: FCR conversion the "burned way". Their are a couple jets that were not mentioned (the slow air jet and the starter jet). What size jets are recommended?

I have ordered a Zip Ty fuel mixture screw (FMS01) also. How many turns should this be set at?

I'm running at +/-1636 ft. elevation.

Thank you

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Can you be more specific as to the source or original application of the FCR you have. I makes a difference in the jetting. OEM Suzuki FCR uses a 65 starter jet. I think Yamahas were larger. "slow jet" is not specific enough. Fuel jet or air jet? In the OEM Suzuki carb there are 2 slow air jets and 1 slow fuel jet (pilot jet is what it is usually called) used in conjunction with the coast enrichener (CE) system which is usually removed and Yamaha did not use at all. So??? -- give me more info.

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Ok, I think I see what you are asking. In "Suzuki speak" "Slow Air Jet" is the Pilot Air Jet and the "Air jet" is the one that gets plugged off when the CE is removed. You have several options. CE removed (or never had it), use a 70 air jet with a 38 fuel jet or a 100 air jet with a 45 fuel jet or replace the air jet with an adjustable Pilot Air Screw (PAS) available from SUDCO and adjust to correspond with fuel jet of your choice - 38 thru 48.

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I think it came off a 2002 YZ426.

I'm using Sudco's FCR MX diagram to name the jets. It is very similar to my carb. all the jets are in the same place.

My carb doesn't have a leak jet (not drilled or tapped) to control accelerator pump out put.

Not "slow jet" but "slow air jet" (no. 30 on the diagram) in the back next to the main air jet.

Looking up into the bottom of the carb. the jet (no. 29 on the diagram) I think is called the "starter jet"

I'm going to be away for a couple days talk to you soon.

Thanks for all your help.

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you may want to think about a ferrea valvetrain upgrade if you plan on using that yosh CDI.

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So, if I use a Pilot Air Screw (PAS) what fuel jet is best to use?

Is this fuel jet referring to the main air jet? [Right beside the air jet or (PAS)]

+/- 1636 ft.

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For the FCR with the external AP as used by Suzuki DRZ400E as OEM (not the MX carb with leak jet AP), the PAS is a good choice and extablished practice is to set he PAS at 5/8 turn open and use a 38 pilot fuel jet. The pilot fuel jet is in the float bowl down kind of a long hole. The Pilot fuel jet is 15mm long which you may need to know when you go to buy one. If you post what pilot fuel jet you have, I can recommend the PAS setting to work with what you have.

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I ordered a 45 pilot jet per the sticky: FCR conversion the "burned way".

Do you suggest a 38 if I use a PAS?

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My pilot jet is 3 cm. long. After talking with Sudco, we think my carb. is a 21 Series. I have ordered a 38 pilot jet & a Pilot Air Screw (PAS).

I also have a Zip Ty fuel mixture screw coming. Can you tell me whare to set both the Fuel Mixture Srew & the PAS.

+/- 1636 ft.

Thank you

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