FCRMX41mm heads up

4 replies to this topic
  • rmhrc630

Posted December 25, 2006 - 10:03 PM


As many of you may know I recently fitted a new FCRMX41mm to the beloved XR628 full house bike:

Posted Image

As many of you also know Sudco are the ones who make the adaptors to enable the FCR to mount to the Honda XR airbox boot.

The aftermarket FCRMX (as opposed to the OEM style FCRs) are made to fit many many different machines. Basically you alter the adaptor and you can for the FCR (space permitting) to any bike.

Now I fitted my adaptor to the FCR body with the 2 supplied allen head bolts and black oring. The stange thing was the oring was visible. I didnt know any better. After my first ride I could smell fuel. Never worked out what it was. Then I did a second ride and saw where it was coming from - the gap (yes ****ing gap) between the adaptor and the carb body.

Now just yesterday I pulled the carb apart and thought maybe I didnt nip the 2 allens up proper.

When I checked I found they were in fact very tight so that wasnt the problem.

I had a spare adaptor. So I fitted that and it was perfectly flush!!!! I refitted my first adaptr and it wasnt!!!

The issue was maching from sudco!!! Their hole for one of the 2 airjets was not deep enough to fit over the jet protrusion from the carb body, which never allowed the adaptor to pull down nice and tight.


(Mine only had 5.2mm and the lack of sealing allowed fuel to seep through the gap!!!)

This is a heads up to anyone contemplating FCR adaptors - make sure the larger of the air jet holes is at least 6.8mm deep, otherwise the adaptor will not fully seat against the carb body and you're sucking air)

I have not investigated motor damage - suffice to say Sudco Australia will be getting a call)

  • frankstr

Posted December 26, 2006 - 07:25 PM


Thanks for info....rmhrc630.....:lol:

:confused: :confused:

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  • exaresix

Posted May 24, 2007 - 05:20 PM



I finally bought a FXR MX 41 for my xr600r. I'm having some problems with fitting it, so I thought I'd ask you how you managed to get yours in so nicely. When I put mine in with the Sudco adapter, the pulley area of the carb hits the frame. Even with the black plastic cover off, the carb still has to sit at quite an angle to keep from hitting the upper frame. I see that yours fits so well that you can even put your plastic cover right on...what's your secret?



  • martinfan30

Posted May 25, 2007 - 09:14 AM


hope it works for you. my slant fcr still works great, altho (dumb question comming!) i cant find its idle mixture screw!:)

  • exaresix

Posted May 25, 2007 - 09:28 AM


I still have my slant 41. I'm going to get one with a choke tho'.


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