Jump to content
Sign in to follow this  

FCR Needle Question

Recommended Posts

I'm replacing the needle in my FCR from the stock DXP to the EMN needle and understand that i need to step down my main jet from a 165 to 160 (i'm running a full open RS-3 at sea level).

Could someone (Eddie) explain how this works? I understand that the EMN must be tapered more, but i thought the needle pulled all way out of the main jet so that at full throttle the needle has no effect on what MJ to use? Please explain/educate me (us).

Share this post


Link to post
Share on other sites

As I understand it, all the fuel that gets to the needle jet, first has to go through the main jet, so to an extent a smaller main jet will lean the needle range as well.

This is why you should re-jet a carb from full throttle downwards.

So,

1/float level, 2/ Main jet. 3/ Needle and clip position. 4/ Pilot Jet. 5/Fuel screw.

Each jet will affect the top end of the jet below it, due to the overlap between jets.

There is a diagram in the Dyno Jet kit that shows this.

The float level will affect all settings.

Neil. :thumbsup::ride::applause:

Share this post


Link to post
Share on other sites

I see. I will report on the DXP to EMN needle change tomorrow morning. See what kinda difference it makes. Hope I can tell.

How do you know where the float bowl needs to be adjusted too?

Share this post


Link to post
Share on other sites
.......

How do you know where the float bowl needs to be adjusted too?

The Keihn spec that I have calls for 9 mm for all FCR's.

Share this post


Link to post
Share on other sites

Bike runs about as good as I think possible now. Noticable difference in power. Pulls harder longer now. With the right jetting and the full RS-3, the bike has pretty impressive grunt. Gonna need cams next! Thanks for all the help TTers and Burned!

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×