Jetting the Flat FCR carb PART DEUX. DISASTER STRIKES!!!!!


38 replies to this topic
  • ARin

Posted November 17, 2005 - 01:13 PM

#21

I think the lesson to be learned, is maybe stuff a rag into the intake port of the head when rejetting the carb...

  • Lowedog

Posted November 17, 2005 - 09:31 PM

#22

I normaly like to pull the carb out completly and do jetting change at the bench.

:applause: Lowedog

  • Indy_WR450

Posted November 18, 2005 - 04:21 AM

#23

I normaly like to pull the carb out completly and do jetting change at the bench.

:applause: Lowedog


Ditto! I pull the carb every time so I can use carb cleaner and completely clean the residue and build up inside. Also it keeps from stripping the heads on the soft phillips screws on the carb. :ride:

  • SpeedBlitz

Posted November 18, 2005 - 05:54 AM

#24

Ditto! I pull the carb every time so I can use carb cleaner and completely clean the residue and build up inside. Also it keeps from stripping the heads on the soft phillips screws on the carb. :applause:


I replaced the soft philips screws with socket head cap screws. Works really well. I got the tip from a past thread. Pulling the carb off is great when you already know what you want to put in, but if your testing jetting, it takes too much time when your on the side of the trail.

  • Indy_WR450

Posted November 18, 2005 - 06:17 AM

#25

No need for guess work when you follow the recommendations on this forum. Jetting will be very close and ridable no matter where you go. Here is a basic chart I have developed baesd on my riding over the last few years in 21 states and all kinds of conditions. Keep in mind once you determine your bike to be on the rich or lean side of this chart based on your particular bike mods you can then make your own chart and stop the guess work for your bike! :applause:

Here is what works for me and you guys can use it as a starting point to jet your bikes:
This recommendation requires air box flow mods and an open stock or aftermarket pipe and ACV circuit intact.

Elevation 0 to 4,000. feet

30 to 45 degrees: 172 main, JD Blue #5, 48 Pilot, 2.0 turns, 75 starter jet, #0 leak jet
45 to 60 degrees: 170 main, JD Blue #4, 48 Pilot, 1.75 turns, 72 starter jet, #0 leak jet
60 to 75 degrees: 168 main, JD Blue #3 or JD Red #5, 48 Pilot, 1.5 turns, 70 starter jet, #40 leak jet
75 to 90 degrees: 165 main, JD Red #5, 48 Pilot, 1.25 turns, 68 starter jet, #50 leak jet
90 degrees plus: 160 main, JD Red #4, 45 Pilot, 2.0 turns, 65 starter jet, #60 leak jet

Elevation 4,000 to 8,000 feet:

30 to 45 degrees: 170 main, JD Blue #4, 48 Pilot, 1.75 turns, 72 starter jet, #0 leak jet
45 to 60 degrees: 168 main, JD Blue #3, 48 Pilot, 1.5 turns, 70 starter jet, #40 leak jet
60 to 75 degrees: 165 main, JD Red #5, 48 Pilot, 1.25 turns, 68 starter jet, #40 leak jet
75 to 90 degrees: 165 main, JD Red #5, 45 Pilot, 2.0 turns, 65 starter jet, #50 leak jet
90 degrees plus: 160 main, JD Red #4, 45 Pilot, 1.75 turns, 65 starter jet, #60 leak jet


Elevation 8,000 to 11,000 feet: ( Note you will loose a lot of power due to altitude but your bike will idle and not foul plugs!)

45 to 60 degrees: 165 main, JD Red #5, 48 Pilot, 1.25 turns, 70 starter jet, #40 leak jet
60 to 75 degrees: 160 main, JD Red #4 , 45 Pilot, 1.75 turns, 68 starter jet, #50 leak jet
75 to 90 degrees: 158 main, JD Red #3, 45 Pilot, 1.5 turns, 65 starter jet, #60 leak jet

  • SpeedBlitz

Posted November 18, 2005 - 09:54 AM

#26

No need for guess work when you follow the recommendations on this forum. Jetting will be very close and ridable no matter where you go. Here is a basic chart I have developed baesd on my riding over the last few years in 21 states and all kinds of conditions. Keep in mind once you determine your bike to be on the rich or lean side of this chart based on your particular bike mods you can then make your own chart and stop the guess work for your bike! :applause:

Here is what works for me and you guys can use it as a starting point to jet your bikes:
This recommendation requires air box flow mods and an open stock or aftermarket pipe and ACV circuit intact.


Indy, Thanks for the info. Believe me, I have seen your chart and gone through the Jetting database, but since I have the ACV circuit disabled, my PJ size and FS setting will be different. Also, since I don't really have a good feel for jetting yet (prior riding experience is crotch rockets with EFI), I want to test so I can get a better feeling for rich/lean conditions for the different circuits, etc... so I can have a better idea of what is going on, and basically, educate myself on jetting through testing. I have probably ridden my WR about 15 times in the last three years, and most rides are about 30-50km. I have spent more time reading the famous "Jetting Qs" thread than actual seat time on my WR!! Pretty sad I know, but that's how it goes I guess. I'm lucky TT is around, otherwise I would have a serious case of withdrawal!!

Also, I have found that the YZFs seemed jetted leaner on the MJ and even leaner on the PJ then expected (WR's seem to run 45-48 PJ and I have seen some YZFs 38-40. with the ACV disabled on my WR, I expected my WR to be in the 40-42PJ range, but I have a feeling that it is still too rich, so I might try to jet closer to the YZFs and see) and after readind the Jetting Qs thread, I'm want to go with a richer needle setup and drop the MJ and PJ size, kind of like Taffy did in the Jetting Qs forum.

  • ARin

Posted November 30, 2005 - 10:39 PM

#27

In case anyone is interested, i have ordered yet ANOTHER new intake valve, to replace the "new" one that i also used to grind/lap the seat. Im sure i destroyed the TI-nitride coating, rendering the valve to wear at honda-like speeds.

  • Indy_WR450

Posted December 01, 2005 - 04:47 AM

#28

Have at it Speedblitz and let us know what else you discover about jetting.
Me I would rather ride then spend all day playing with jets. :applause:
My next bike will be EFI and hopefully a Yamaha! I am waiting!!!!!!!! :ride: :p :p

  • SpeedBlitz

Posted December 01, 2005 - 06:19 AM

#29

Believe me, I don't want to spent all day playing with jets, especially considering how little riding I do, but I owe it to myself to learn to feel the difference between lean and rich. Unless you are willing to workout your jetting table down to -30 dec C? Than I'll be all set to hit the ice in January!!

Definitely can't wait for the EFI bikes, and like you said, sure hope it's a Yamaha. I'll be first in line at my dealer.

BTW, how did you work out your table Indy? Did you find a baseline setting that worked well and then apply correction factors for altitude and temperature and then each time you would ride in a an area with a specific altitude and temp, try out the jetting you had and see if it worked and tweak it if necessary?

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  • SpeedBlitz

Posted December 01, 2005 - 06:49 AM

#30

Me I would rather ride then spend all day playing with jets.


Indy, I can't get this quote out of my hand!! The hell with the jetting testing I wanted to do! I'll put back the ACV diaphragm and use your chart. I'll have to compensente for the temperature though since it's currently around -20C.

  • kincade

Posted December 01, 2005 - 04:37 PM

#31

Indy and Lowedog; when you pull the carb, how exactly do you do it? I'm sick of jetting this carb on the bike, what a PITA! Last time I broke the dang hot start nut on top...

TIA!

  • Indy_WR450

Posted December 01, 2005 - 05:20 PM

#32

To remove the carb:

Take the tank & seat off.
drain the float bowl
Remove regulator on right side of frame
remove hose clip on right side of frame holding regulator and hoses
remove the cover on right side of carb
disconnect the throttle cables at the carb
loosen the intake boot
lossen the air box boot
remove the hot start cable at the carb
disconnect the tps and unclip the tps cable tie
use a rubber mallet handle and pry the air box boot away from the carb by using the frame for a pivot point on the handle adn the end of the handle on the boot
pull the carb away from the air box boot on the left side of the bike
pull the carb out of the intake boot
you now have the carb to put on a bench or vise and rejet and clean. Mine gets dirty so cleaning the carb with carb cleaner is always a good idea. :applause:

  • MotoGoalie

Posted December 02, 2005 - 07:39 AM

#33

Indy and Lowedog; when you pull the carb, how exactly do you do it? I'm sick of jetting this carb on the bike, what a PITA! Last time I broke the dang hot start nut on top...

TIA!


Buy the aluminum hot start nut from zip ty. We've all broken that little pos plastic nut. :applause:

  • kincade

Posted December 02, 2005 - 09:24 AM

#34

So; the only connections that you have to disconnect are the 2 throttle cables, TPS plug, and the hot start cable? MAN, I would have done this a long time ago had I known that! that thing is a BEATCH to rejet IN the bike.

Thanks for the heads up MotoGoalie; I didn't know there were any aftermarket parts for that!

  • Indy_WR450

Posted December 02, 2005 - 10:18 AM

#35

Buy the aluminum hot start nut from zip ty. We've all broken that little pos plastic nut. :ride:


Ditto eveyrone runs the red aluminum nut from Zip Ty !!!! :applause:

  • MotoGoalie

Posted December 02, 2005 - 10:22 AM

#36

So; the only connections that you have to disconnect are the 2 throttle cables, TPS plug, and the hot start cable? MAN, I would have done this a long time ago had I known that! that thing is a BEATCH to rejet IN the bike.

Thanks for the heads up MotoGoalie; I didn't know there were any aftermarket parts for that!


On rejeting in the field.

you don't need to do allthat.

Just undo the rubber tract connections and muscle that thing back and tip it over so you can pull the hex (17mm) screw on bottom. If you look up there, which is awkward you can easily get to the main and pj and change em out in 2 mins easy.

You tilt it the opposite way to get to the top and the Needle jet.

admittedly you need small fingers to do this. My dad has giant sauasages for fingers and couldn't possibly do some of this fine work. I guess it's a good thing I have small girlish hands.

  • ARin

Posted December 21, 2005 - 10:17 PM

#37

ok, as an addendum to this story, it turns out that NO grinding of a titanium valve should be done, regardless of what the manual says. Ti valves have a very THIN very HARD coating on them, that keeps them from wearing. grinding the valve will remove that coating, allowing the valve to wear very quickly. I recently RE-opened up my motor, and replaced that valve again, with a new one. Ordered the parts from Zanotti motors (cheapest).

there was ALSO A problem with the grinding of the shims. When taking apart the motor, we realized that the valve shim buckets had aggresive swirl marks in them. This leads me to believe that the grinding of the shims that we did, is not exactly flat...causing the buckets to sit off kilter, and spin when the cam lobes contact them. All the shims were replaced with brand new Hotcam brand shims. I purchased the whole shim kit for around 60.

SO, in conclusing, dont grind the valve and valve seat, unless you HAVE to like i did. and if you HAVE to, might be better off to take it to an auto machine shop, and let them do it, so you dont trash a valve in the process.

  • Indy_WR450

Posted December 22, 2005 - 09:26 AM

#38

Great points ARin! :applause: :bonk: :cry:

  • ARin

Posted December 22, 2005 - 11:29 AM

#39

Well, this has been a trial and error thing for me....HOWEVER, STILL much cheaper than if i had taken it to a shop or dealer to have this work done.

Im only out a couple hundred bucks on this repair. Im sure a shop would have charged me a mortgage payment.




 
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