2006 ktm 640 adv fcr carb swap

[Maineroot]

Hello-

I am performing a swap for the FCR 41 on my 640.

The install has been straightforward except for the connection to the TPS wires are different.

4 questions:

1. The new carb has a pull type choke- and I wanted to see if it was possible to retrofit the cable actuator to the new FCR

2. The hot start is deleted on the FCR 41 that I have. Is this a major issue?

3. Jetting setup is below. Any comments on this combo- I'm completely unfamiliar with this motor.

NEEDLE:

OBDVR- CLIP 5
170 MAIN
48 PILOT
LEAK JET: 0

Also on the jetting spec that came with the carb is this note:
8557 ARTGR

Not sure what that means!

4. I'm not sure if I knocked a connection off- but there is a dead end plug hanging that has a GREEN/RED and a BROWN wire going to it. It's on the harness near where the TPS enters the harness.

Thanks in advance.

[Luke]

Originally Posted by Maineroot

....

1. The new carb has a pull type choke- and I wanted to see if it was possible to retrofit the cable actuator to the new FCR

I've heard you can, and it looks about right. It's not exact, there's some fiddling involved. I took a look but didn't want the extra cable.

2. The hot start is deleted on the FCR 41 that I have. Is this a major issue?

I don't have it, and have never needed it.

3. Jetting setup is below. Any comments on this combo- I'm completely unfamiliar with this motor.

NEEDLE:

OBDVR- CLIP 5

Not a good needle. Unless you're running full emissions gear or a restrictor. The E taper is much better then the D taper. OCEMR is popular. OBEMR is the same thing but the OEM nickel plated version instead of brass. Here's a chart here that compares the other letters. http://www.sudco.com/vol33/113.pdf

170 MAIN

Close enough to start with. Depends on your exhaust, airbox, elevation, etc.

48 PILOT

Close enough to start with.

LEAK JET: 0

No idea. The AP is pretty rich, there's a Honda kit that cuts the squirt time considerably.

Also on the jetting spec that came with the carb is this note:
8557 ARTGR

Not sure what that means!

Neither do I!

4. I'm not sure if I knocked a connection off- but there is a dead end plug hanging that has a GREEN/RED and a BROWN wire going to it. It's on the harness near where the TPS enters the harness.

If it's actually green/red and orange then it's for the Electronic Power Control. Hook that up if you have too much power.

Thanks in advance.

You're welcome.

[Maineroot]

@Luke-

Thanks for the advice.

The carb came with some extra needles, namely the

OBEKR, which seems like what folks are having good luck with (that I have read here). I'm going with this

OBEKR 4th Clip
170 MAIN
48 PILOT

The bike has the snorkle removed, stock header and FMF can.

Once I get it bolted up, I'll post results.

[Luke]

Sounds good. The K is the same as the M except that the clip grooves are offset by one position.

[LukasM]

I'd say OBEKR 3rd clip, 165 main and 42 pilot. 168 main if you open up the airbox some.

[Lc8grrr]

I used the adv choke with a slight mod into the fcr but can't remember what I did. It'll be easy though.

[LukasM]

Originally Posted by Lc8grrr

I used the adv choke with a slight mod into the fcr but can't remember what I did. It'll be easy though.

File the end flat?

[Maineroot]

Originally Posted by LukasM

File the end flat?

I was wondering how to do the choke mod. The BST choke has a barrel and a pin at the end, and the FCR has just a barrel.

[Hipster]

Maineroot,

If you read through this thread, I believe Creeper had filed off the tip of the stock BST choke http://www.advrider.com/forums/showthread.php?t=206427

[Maineroot]

I'll give that a try with the file. I'd like to keep the choke function on the handlebar.

[Maineroot]

I got everything back together and fired it up, and took it for a ride.

Here are the jetting symptoms.

If you whack the throttle in Neutral- it will bog and die. If you roll it on- no problem.

I ran it through the gears- and it seems to have a "hanging" throttle effect when letting off the gas. Feels like it is running on.

Not sure if this is a mechanical or jetting related.

When re-installing the throttle cables, I was not sure about how tight I had to make the adjusters on the cable at the carb end. Should there be any slack to speak of on either cable? I snugged them both up.

Any thoughts on jetting to get this sorted out?

[smokeeater495]

I installed an FCR on a '96 RXC 620. I had to reroute the throttle cable, only used the pull, behind the bars. When routed like the original cable it was too tight and would open the carb under full lock turns. As far as whacking the throttle open in neutral, how does it run when you whack it open in gear? If I recall my RXC didn't like having that done in neutral either.

[Maineroot]

I put on a set of LONGER throttle cables, so there is plenty of slack.

I'll get the bike out tomorrow for a full shakedown ride. Maybe I just need to mess with the fuel screw.

[Kawidad]

Originally Posted by Maineroot

I got everything back together and fired it up, and took it for a ride.

Here are the jetting symptoms.

If you whack the throttle in Neutral- it will bog and die. If you roll it on- no problem.

I ran it through the gears- and it seems to have a "hanging" throttle effect when letting off the gas. Feels like it is running on.

Not sure if this is a mechanical or jetting related.

When re-installing the throttle cables, I was not sure about how tight I had to make the adjusters on the cable at the carb end. Should there be any slack to speak of on either cable? I snugged them both up.

Any thoughts on jetting to get this sorted out?

The symptoms you describe make it sound like the jetting is too rich at the higher rpm range and possibly squirting too much fuel and/or squirting too long. Having too much unburned fuel will cause some run on feeling.

[Maineroot]

Originally Posted by Kawidad

The symptoms you describe make it sound like the jetting is too rich at the higher rpm range and possibly squirting too much fuel and/or squirting too long. Having too much unburned fuel will cause some run on feeling.

OK- that makes sense. And what would be the solution to this?

Jetting specs are above. Let me know if any of this looks out of whack.