Clear guide to FCR40 jetting on XR650L?

Started by n16ht5, Jan 08 2012 12:29 PM
26 replies to this topic

  • n16ht5

Posted 08 January 2012 - 12:29 PM

#1


Just ordered a crf450 2002 carb for $120 on ebay.

I have been searching for a while now... still lost on where to start jetting.

Looks like to install into bike I need the NOSS adaptor or some sort of tugboat fuel line from NAPA...
stock XRL cables and throttle tube work according to searching..

Jetting- I have seen stock crf jetting to 155main and different needle... what should I try?

xr650l
FMF Q4
desnorkelsmog
header welds ground
uni filter

1000ft-6000ft

I am guessing...
168 main
45 pilot (isnt that stock)?
leave everything else

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  • ThumpNRed

Posted 08 January 2012 - 04:42 PM

#2

n16ht5 said:

Just ordered a crf450 2002 carb for $120 on ebay.

I have been searching for a while now... still lost on where to start jetting.

Looks like to install into bike I need the NOSS adaptor or some sort of tugboat fuel line from NAPA...
stock XRL cables and throttle tube work according to searching..

Jetting- I have seen stock crf jetting to 155main and different needle... what should I try?

xr650l
FMF Q4
desnorkelsmog
header welds ground
uni filter

1000ft-6000ft

I am guessing...
168 main
45 pilot (isnt that stock)?
leave everything else
Look in my TT garage. My jetting specs are there. Your stock cables will work fine... they are the same as CRF cables. Our jetting should be close. Your carb is 40mm, my jetting is for a 41mm on a bit more motor, but it should get you close.

  • n16ht5

Posted 14 January 2012 - 01:22 AM

#3

thanks.ordered jets

  • zx12r

Posted 15 January 2012 - 11:14 AM

#4

The post isn't here anymore. My 04 crf450r FCR MX 40mm carb came jetted, 170 mj, 45 pj, NCYR needle, and it ran great. I did lower the mj to 168. For cold starts, Old Dog had a trick, turn up the idle knob up 2 or three turns, hit the throttle a couple times, to get the AP squirting, and she'll fire right up, then as shes warms up, just turn down the idle little by little, works like a charm(If you don't turn up the idle, even with the choke, she was hard to keep running). These FCR's really do wake up these motors, best mod I've done.

  • n16ht5

Posted 21 January 2012 - 04:37 PM

#5

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  • n16ht5

Posted 21 January 2012 - 04:41 PM

#6

170
42
OCEMN needle (3)
2 turns out.

so far so good. only got to ride in about a foot of slushy snow so Ill see how it rides when it thaws out. I was throwing a 30ft roost of snow and crud behind me, so I think it's going to rip :bonk:.

thanks ThumpNRed, DirtbikeMike, ZX


adaptor is a Napa 2 1/8" fuel line 1.5" long and a 2" abs pipe 2" long

  • martinfan30

Posted 22 January 2012 - 07:37 AM

#7

If you have to turn in your idle screw for cold starting, your pilot circuit is too lean. Go up one step richer on your pilot jet and retest.

  • zx12r

Posted 22 January 2012 - 12:44 PM

#8

View Postn16ht5, on 21 January 2012 - 04:37 PM, said:

Posted ImagePosted ImagePosted Image
Do you have the Napa part# for the 2 1/8 fuel line? All I could find was 2 or 2 1/4 inch Gas filler neck hose when I made mine, (I used 2" it was a tight fit on the carb, but 2 1/4 was to big), 2 1/8 is the correct size. Also make sure the the ABS pipe is not going to deteriorate or melt with gas or gas vapors, I don't know if it will. I used exhaust pipe in mine to make the air box side more rigid for the air box clamp.

  • selztoad

Posted 24 January 2012 - 08:19 AM

#9

View PostThumpNRed, on 08 January 2012 - 04:42 PM, said:

Look in my TT garage. My jetting specs are there. Your stock cables will work fine... they are the same as CRF cables. Our jetting should be close. Your carb is 40mm, my jetting is for a 41mm on a bit more motor, but it should get you close.

I dont believe the throttle cables are the same, I got a RMZ450 fcr40 and the xr650l throttle cables are too long

  • ThumpNRed

Posted 24 January 2012 - 12:14 PM

#10

View Postselztoad, on 24 January 2012 - 08:19 AM, said:

I dont believe the throttle cables are the same, I got a RMZ450 fcr40 and the xr650l throttle cables are too long
The CRF cables and the XRL cables (and throttle assemby) are the same. I have a couple of each at home and they are absolutely interchangeable. I can't speak to cables off of an RMZ... they are likely different considering it is a Suzuki.

  • selztoad

Posted 24 January 2012 - 02:34 PM

#11

View PostThumpNRed, on 24 January 2012 - 12:14 PM, said:

The CRF cables and the XRL cables (and throttle assemby) are the same. I have a couple of each at home and they are absolutely interchangeable. I can't speak to cables off of an RMZ... they are likely different considering it is a Suzuki.
I was told that the CRF thortle tube was a shorter turn than the XRL?

  • n16ht5

Posted 25 January 2012 - 11:57 PM

#12

well I went for a run but it lost top end power. I can barely hit 85mph now.. I am going to try jetting it fatter. I wonder if the 40mm is constricting the power? how big can you bore these?

  • ThumpNRed

Posted 26 January 2012 - 06:17 AM

#13

View Postn16ht5, on 25 January 2012 - 11:57 PM, said:

well I went for a run but it lost top end power. I can barely hit 85mph now.. I am going to try jetting it fatter. I wonder if the 40mm is constricting the power? how big can you bore these?
I wouldn't think that one mm would make that much difference... m 41 screams on top. I would try jetting the main a bit fatter... or raise the needle a notch and see where that gets you. btw... Cycle Wizard over on ADV has developed a spacer that goes between the carb and the intake manifold that fixes the airbox gap. I am thinking about getting one and trying it out on my spare FCR.

  • zx12r

Posted 26 January 2012 - 11:09 AM

#14

View Postn16ht5, on 25 January 2012 - 11:57 PM, said:

well I went for a run but it lost top end power. I can barely hit 85mph now.. I am going to try jetting it fatter. I wonder if the 40mm is constricting the power? how big can you bore these?

The 40mm FCR is not your problem, thats what I have on mine and it added a top end hit that she didn't have with the CV carb and I'm running a 168 main jet. I never hit the rev limiter with the CV and can easily hit it with the 40mm FCR, not that I hit it much, your past the power when you hit the limiter. She'll go around 100mph, with stock gearing, can't hit the rev limiter in top gear though. Do you have that piece of PVC pipe butt up against the back of the carb? There are air orifices back there that need to get air. You could just cut a notch in the PVC, were the air holes are.

  • ThumpNRed

Posted 26 January 2012 - 11:12 AM

#15

View Postzx12r, on 26 January 2012 - 11:09 AM, said:

The 40mm FCR is not your problem, thats what I have on mine and it added a top end hit that she didn't have with the CV carb and I'm running a 168 main jet. I never hit the rev limiter with the CV and can easily hit it with the 40mm FCR, not that I hit it much, your past the power when you hit the limiter. She'll go around 100mph, with stock gearing, can't hit the rev limiter in top gear though. Do you have that piece of PVC pipe butt up against the back of the carb? There are air orifices back there that need to get air. You could just cut a notch in the PVC, were the air holes are.
Good point zx. There are air inlets on the mouth of the inlet. The NOSS adapter has a cut out for them.

  • zx12r

Posted 26 January 2012 - 11:30 AM

#16

View PostThumpNRed, on 26 January 2012 - 06:17 AM, said:

btw... Cycle Wizard over on ADV has developed a spacer that goes between the carb and the intake manifold that fixes the airbox gap. I am thinking about getting one and trying it out on my spare FCR.
I looked on ADV(thousands of posts, I gave up) and couldn't find the FCR adapter that cyclewizard sells. Do have a link?

  • ThumpNRed

Posted 26 January 2012 - 11:51 AM

#17

http://advrider.com/...postcount=37305
Here's the link to CW's adapter.

  • zx12r

Posted 26 January 2012 - 12:08 PM

#18

View PostThumpNRed, on 26 January 2012 - 11:51 AM, said:

http://advrider.com/...postcount=37305
Here's the link to CW's adapter.
Thanks, Whats he sell them for, money wise?

  • ThumpNRed

Posted 26 January 2012 - 03:24 PM

#19

View Postzx12r, on 26 January 2012 - 12:08 PM, said:

Thanks, Whats he sell them for, money wise?
I would rather leave that question for you and him to discuss. The number I got did not make me flinch.

  • n16ht5

Posted 26 January 2012 - 05:48 PM

#20

hmm. Ill try a 175 main. I dont know the part # for the hose, sorry
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