Triumphrat

sbpark · 11-20-2009, 11:08 PM

just wondering what those of you who live at sea level are using for jetting of your FCR's? i have the FCR's on my thruxton, 865 motor, 813 cams, ported and polished head with 5 angle valve job, predatirs, ARK, UNI filters...

what are your main jets, pilot lets, how many turns out on your slow air screws and idle mixture screws?

thanks everyone!

propforward · 11-21-2009, 06:29 AM

I'm currently running

55 slow, 138 main, FBR needle clip on posn 4. This runs well for me in the cold temperatures. Once it gets back up above 60 degrees I use the EMR needle with clip on position 6.

HOOPLA · 11-21-2009, 09:58 AM

Hello again sbpark,

I responded to one of your earlier lines, my set up was determined with the use of the AF gauge I spoke about.

I use Domminator touring pipes and Uni filters, head is stock.

I have an early 2001 790 Bonnie, for some reason my bike set up differently, what it is cams, heads, I don''t know, but I haven't ruled out faultly fuel pump adjustment yet. I plan on making the fuel pump manuel, off of the throttle in the spring. You can reach in behind the heads and push the plunger down with your finger.
So having said that, my set up is as follows:

The following set up ran well at 30.3 in pressure 75F 50% rh, I'm 300-600 feet above sea level normally.

Needle DVR slot #5 from top
Main 148
Slow jet 55
Main air jet 200
Fuel screw 1 5/8
Air screw 1 1/2
Idle screw left 1
Idle screw right 1

As I mentioned before you need to find and be able to change all of the above. It takes a while to learn what items effect the various areas of the AF curve.

When you adjust the air and fuel screws, before you do, scribe a line as a reference to move from, I have found that 1/8 turn adjustments are enough when you're close in this area of the AF curve.

Keep at it

Hoopla

sbpark · 11-21-2009, 08:47 PM

wow, 72 views and only 2 replies?! i know everyone's jetting will be different since a lot of us have different mods, displacement, etc, but c'mon!

anyway, i think i finally got the carbs dialed in fairly well. started a seperate post on what i ended up with and how i got there...

HOOPLA · 11-23-2009, 01:59 PM

I'm not surprized that you got so few responces, cause I don't think many people have tuned their own carbs.
The responces you do get are good in general, don't hope for an exact set up that's why you need to get an AF gauge or spend lots of time on the dyno.

Hoopla

mikeinva · 11-23-2009, 02:42 PM

Quote:

Originally Posted by HOOPLA

I'm not surprized that you got so few responces, cause I don't think many people have tuned their own carbs.
The responces you do get are good in general, don't hope for an exact set up that's why you need to get an AF gauge or spend lots of time on the dyno.

Hoopla

+1 on that and one thing that all of us that know alittle about tuneing motors there is no one size that fits all thats why its called tuneing.what works on one guys bike may be way off on anothers.

PieMan · 11-23-2009, 04:36 PM

These are the details of an 865 running FCR39's.

Staintunes, DNA Pods, Keihin FCR39's, headwork, Wiseco 10.5:1 pistons, 813 cams, Igniter mods.

145 mains
55 pilots
OC-EMR (pos 5)
P1.5
A1.75

sbpark · 11-23-2009, 05:07 PM

Quote:

Originally Posted by PieMan

These are the details of an 865 running FCR39's.

those numbers look great with that set-up with the higher compression on the stock motor.

mikeinva · 11-23-2009, 05:18 PM

Thats pretty good mike what did the head have done to it? os valves?

PieMan · 11-23-2009, 05:27 PM

Porting with OEM valves.