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Unique carb/pipe combo help with jetting.

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I have my bike perfectly set-up (2009 DRZ400 B.B.kit, hot cams, MRD-SSW full exhaust, FCR-39 carb) however, due to local track noise restrictions I have to throw on the stock exhaust. Is there anyone running a stock exhaust with a FCR-39 carb @ sea level? What needles and jets are you running? I know it is doubtful but this is better than me messing about for hours on end. Perhaps I'll get a starting point. Thanks in advance! S.

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That will not cut it here. Thanks though. Anyone run FCR with stock pipe?

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Mite I suggest a 150 main jet to go with the EMP needle , clip #3

OR

you could just try running it without the air box door ,.... but that would give you more induction noise and it still may not conform to the conformists noise regs... :moon::bonk:

OR

install a stock "Real E" exhaust system as they flow really well and by doing this you could leave your jetting "as is".... :D

Edited by Craigo 485sm

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Real E pipe and muffler is not the same in the Americas as it is un AU or UK. Only the header on the American bike is like yours, the muffler is the same as a S/SM

Bugger...you guys got a bad deal there.. :cry::lol:

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Craigo,

Seeing how the E is not the same, my other option of running it with air box cover off sounds decent. The track is not that picky, compared to the MRD-SSW I'm sure it will be a mouse. Thanks guys!

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Made the swap from the MRD to the stock without touching the carb. Surprisingly, it runs really well. However, it feels like I lost 10hp! I can't believe the difference in the low end that the MRD produces. Thanks for the input.

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Made the swap from the MRD to the stock without touching the carb. Surprisingly, it runs really well. However, it feels like I lost 10hp! I can't believe the difference in the low end that the MRD produces. Thanks for the input.

What carb is fitted??

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Carb is from Eddie FCR-39 pre-set to sea level.

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Made the swap from the MRD to the stock without touching the carb. Surprisingly, it runs really well. However, it feels like I lost 10hp! I can't believe the difference in the low end that the MRD produces. Thanks for the input.

Carb is from Eddie FCR-39 pre-set to sea level.

Rejet it and it will only feel like you lost 4 to 5 hp....... :)

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Craigo, thanks. Do you think I would have any gains with your previous suggestion (removing the airbox cover)? I am only hitting the track once a month and changing my jetting each time would be a total PITA. Cheers, S

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Craigo, thanks. Do you think I would have any gains with your previous suggestion (removing the airbox cover)? I am only hitting the track once a month and changing my jetting each time would be a total PITA. Cheers, S

The only way to accurately tell if the jetting is close without the airbox door is to run it on the dyno taking air/fuel readings....

You could do a little "seat of your pants" testing prior to the day , the engine with let you know if it's not right.....

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Thanks! As it is, I can live with it. However, one always would like more hp. cheers, S.

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