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Old 11-26-2011, 12:56 PM   #6841
Reckless Relic
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Try a JD kit

Quote:
Originally Posted by juames View Post
I need to pick the collective brains of the LC4 crowd around here.

Anyone fit a FCR-41 on thier 640Adv? Looking for jetting advice. I have a fairly stock 2002 with low-flow head and SXC exhaust. The carb has jetting for a Duke from Sommers not sure if that will work too well with my bike. Any advice would be great.

Maje-appreche!
Hi Juames, I run a 39 FCR on my 2003 and use a JD Jetting kit for the 625 sxc bike has never run better the only thing I needed to change was the pilot jet the kit suggests a #45 but Ive ended up running a #40
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Old 11-26-2011, 01:34 PM   #6842
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What made you change to #40?

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Originally Posted by Reckless Relic View Post
Hi Juames, I run a 39 FCR on my 2003 and use a JD Jetting kit for the 625 sxc bike has never run better the only thing I needed to change was the pilot jet the kit suggests a #45 but Ive ended up running a #40
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Old 11-26-2011, 04:21 PM   #6843
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What made you change to #40?
Just too rich of the very bottom for the 39 FCR I found it hard to start after a down hill at no throttle the #40 pilot jet cleaned it up without a problem.
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Old 11-26-2011, 06:20 PM   #6844
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Thanks for the replies! After some research I think this will be my starting point:

42 pilot jet
100 pilot air jet
1 3/4 turns out
needle #3 clip position (3rd from top)
170 main jet

I'm going to send off a email JDJetting to see if I'm on the right track also.
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Old 11-26-2011, 06:45 PM   #6845
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Quote:
Originally Posted by juames View Post
Thanks for the replies! After some research I think this will be my starting point:

42 pilot jet
100 pilot air jet
1 3/4 turns out
needle #3 clip position (3rd from top)
170 main jet

I'm going to send off a email JDJetting to see if I'm on the right track also.

You'll for sure gain some snap with the FCR but don't be surprised if you lose 100-200 KMs of fuel range per tank... Some guys with FCRs are going onto reserve at around 300 KM as to where a properly working BST will do 450-500 KM to reserve...

Fuel economy and fuel range is a priority for my type of riding so I have stuck with the BST despite it's shortcomings... You may want to keep your BST and swap it in if your going to run long distance trips like the TCAT for instance and then swap back to the FCR for fun blasting...
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Old 11-27-2011, 04:12 AM   #6846
juames
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Quote:
Originally Posted by gunnerbuck View Post
You'll for sure gain some snap with the FCR but don't be surprised if you lose 100-200 KMs of fuel range per tank... Some guys with FCRs are going onto reserve at around 300 KM as to where a properly working BST will do 450-500 KM to reserve...

Fuel economy and fuel range is a priority for my type of riding so I have stuck with the BST despite it's shortcomings... You may want to keep your BST and swap it in if your going to run long distance trips like the TCAT for instance and then swap back to the FCR for fun blasting...
Lose 200k!!??! I only get 350 before reserve now!
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Old 11-27-2011, 08:27 AM   #6847
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Lose 200k!!??! I only get 350 before reserve now!
That's about 100 less than my 03, even when I push my bike very hard I always get better than 400 KM to reserve... I would think something is not right within your BST, worn parts like the slide,jet needle and needle jet come to mind... Could be overly fat jetting, what size jets are you running? Do you notice a frequent fuel weep out the bottom drain tube possibly indicating a worn float needle?

On the bright side, when you switch carbs, you shouldn't notice a whole lot of difference in range when your only going 350 KM to reserve with the BST now...
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Old 11-27-2011, 08:32 AM   #6848
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Quote:
Originally Posted by gunnerbuck View Post
That's about 100 less than my 03, even when I push my bike very hard I always get better than 400 KM to reserve... I would think something is not right within your BST, worn parts like the slide,jet needle and needle jet come to mind... Could be overly fat jetting, what size jets are you running? Do you notice a frequent fuel weep out the bottom drain tube possibly indicating a worn float needle?

On the bright side, when you switch carbs, you shouldn't notice a whole lot of difference in range when your only going 350 KM to reserve with the BST now...
Not sure what jets are in the carb right now...have not had it a part yet. No fuel leakage. When I take of the CV to install the FCR I'll open it up and take a look.
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Old 11-27-2011, 08:44 AM   #6849
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I rebuilt my engine last year as to where I re-ringed the piston and had the cylinder honed.. Since doing that my fuel economy has been poorer.... Pre rebuild I often went 470-500 KM to reserve, post rebuild 450 km is about it till the fuel light is flashing... I suppose the slightly looser fit of the piston has something to do with it... When I get my 2nd 03 Adventure up and running I'll be able to compare the #s as it will have pretty much the same setup as my prime bike...
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Old 11-27-2011, 08:30 PM   #6850
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Quote:
Originally Posted by juames View Post
I need to pick the collective brains of the LC4 crowd around here.

Anyone fit a FCR-41 on thier 640Adv? Looking for jetting advice. I have a fairly stock 2002 with low-flow head and SXC exhaust. The carb has jetting for a Duke from Sommers not sure if that will work too well with my bike. Any advice would be great.

Maje-appreche!
You could try this googling these search terms:

ktm 640 2002 fcr41 jet site:www.advrider.com
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Old 11-29-2011, 12:11 PM   #6851
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2001 640 full remus exhaust 17 inch rims for summer and enduro for the rest of the year great fun for the money
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Old 11-29-2011, 02:43 PM   #6852
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Quote:
Originally Posted by gunnerbuck View Post
I rebuilt my engine last year as to where I re-ringed the piston and had the cylinder honed.. Since doing that my fuel economy has been poorer......
Funny, my fuel usage has only ever changed much when my carb was worn out. Post rebuild with new piston, rings & a light cylinder hone she uses about the same as before.

Re FCR fuel usage, it really depends on setup & how much you twist. A friend has one (39mm IIRC) on his 04 640E & gets about the same economy as me on my BST'd 03.

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Old 11-30-2011, 12:56 AM   #6853
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Quote:
Originally Posted by clintnz View Post
F

Re FCR fuel usage, it really depends on setup & how much you twist. A friend has one (39mm IIRC) on his 04 640E & gets about the same economy as me on my BST'd 03.

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Same here, FCR39 and around 430 km's to reserve...
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Old 11-30-2011, 02:05 AM   #6854
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Same here, FCR39 and around 430 km's to reserve...
Thats the sort of range I get with the 39 FCR, Ive compared it to a mates BST40 before he fitted a FCR and they where pretty much the same in normal riding. Now twistthe right wrist with the FCR and engage the fun factor and then you will use a bit more fuel but you only live once so why not.
Last year crossing the Simpson desert I used 41 liters to cover the 640km which by all accounts seems pretty normal.
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Old 11-30-2011, 02:14 AM   #6855
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Quote:
Originally Posted by Reckless Relic View Post
Now twistthe right wrist with the FCR and engage the fun factor and then you will use a bit more fuel but you only live once so why not.
Probably not as long as with the BST though
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