Changing Slow Jets on FCR's

[eonan]

Has anyone had experience of changing the slow jets on a set of FCR carbs?

As far as I can tell, I have to remove the covers of the float chambers, then the float bowls in order to access the jets.

My first question is this: I remember reading somewhere that by turning a set of carbs upside down, it destroys something in them? Can’t remember what or why, just that it was a bad thing to do. It’s just that in order to change these jets, it looks like I’m going to have to turn them upside down.

The second question is: How do I get the right hand chamber cover off? It has a mechanism (red arrow) that is attached to the cover at one end, and to the main body of the carbs at the other. So, what do I need to do with this mechanism?

[CK & AK]

AK is out at the mo - worth you dropping a PM to Crust who might be able to help as he has some............

C:)

[eonan]

Cheers CK :) Managed to get them off...it's amazing how something so simple can seem so daunting when you don't know how it works :fou:

It should be plain sailing from now on, but the existing jets seem to be welded in there! Are they supposed to be seated so tightly? They're brass, and pretty soft, so before I destroy any chance of ever getting them out of there, I'm off to Halfords to buy the EXACT size of screw driver!

[eonan]

OK, the jets are changed (we'll start with the 55's and take it from there), and the carbs are back on the bike :thumbsup:

Finding out whether I've buggered things royally is going to have to wait until tomorrow though...right now, I'm off to a friend's wedding :drunk:

[eonan]

Result :mand:

Revs now consistently drop down to 800 (although this may have been to do with the poor compression feedback of the horizontal cylinder), much of the lurching between 0 – 1/8th throttle has been smoothed out, in all gears, and finally, rev matching when down shifting seems much, much smoother.

To be honest, the 52’s will probably be even better, so next crappy day they're going in :thumbsup:

[antonioshabirto]

Result :mand:

Revs now consistently drop down to 800 (although this may have been to do with the poor compression feedback of the horizontal cylinder), much of the lurching between 0 – 1/8th throttle has been smoothed out, in all gears, and finally, rev matching when down shifting seems much, much smoother.

To be honest, the 52’s will probably be even better, so next crappy day they're going in :thumbsup:

which size of fcr are u using ?? and how do u optain the other size of the slow jet ? where did u buy them ?

[eonan]

which size of fcr are u using ?? and how do u optain the other size of the slow jet ? where did u buy them ?

41's

The carbs are from CA Cycleworks in the US and the jets can be purchased from Allen's Performance R&D Ltd here in the UK.

[antonioshabirto]

41's

The carbs are from CA Cycleworks in the US and the jets can be purchased from Allen's Performance R&D Ltd here in the UK.


41' for which bike bro ?? m900 ??

i intend to get the 41 for my m680 but some saying its too big

while some say its very responsive

[eonan]

41' for which bike bro ?? m900 ??

i intend to get the 41 for my m680 but some saying its too big

while some say its very responsive

This was for the M750. It's usually recommended that the 750 gets the 39's, but I would absolutely go for 41's over the 39's on this bike. As for your 680, I've no idea mate, sorry...I don't know enough about them.

Give Chris at CA Cycleworks a call...what he doesn't know about FCR's isn't worth knowing :thumbsup: www.ca-cycleworks.com