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TT Keihin FCR 39 mm carb drain gas leak - warranty?

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I have TT Keihin FCR 39 mm carb (kit bought from TT) on my 2008 DRZ400SM.  Gas is coming from the drain hose at the bottom of the bowl when parked or riding.  I doubled checked to make sure the drain screw was tight and it was.  I loosened it all the way, and then tightened it again - problem still exists.

I have read the floater might be stuck, tapped on the float bowl with the plastic handle of a screw driver in an attempt to free the floater if it was stuck – no success, the leak is still there.  It is not flowing heavily, but overnight it drips very slowly, and fills about 2 inches of a small water bottle.

 

Does anyone know if this is covered by TT’s warranty.  I bought it brand new from TT few years ago so it might not be... :(

 

Or any suggestions on how to fix this issue – my garage smells like gas  :banghead:

 

Thanks!

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I did not overscrew the drain screw, and have not touch it before, until y'day...so doubt it is damaged.  I did not open the carb in any way, this was a kit bought from TT, so doubt the float got moved.

 

I am suspecting the other two you pointed:

 

  • Debris on the float needle valve
  • Cracked float needle valve seat oring

Anyone has a picture of what these are and how to fix it?

 

 

 

 

 

Edited by ratu

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Is that manual for thumper FRC carb? 

Edited by ratu

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I have TT Keihin FCR 39 mm carb (kit bought from TT) on my 2008 DRZ400SM.  Gas is coming from the drain hose at the bottom of the bowl when parked or riding.  I doubled checked to make sure the drain screw was tight and it was.  I loosened it all the way, and then tightened it again - problem still exists.

I have read the floater might be stuck, tapped on the float bowl with the plastic handle of a screw driver in an attempt to free the floater if it was stuck – no success, the leak is still there.  It is not flowing heavily, but overnight it drips very slowly, and fills about 2 inches of a small water bottle.

 

Does anyone know if this is covered by TT’s warranty.  I bought it brand new from TT few years ago so it might not be... :(

 

Or any suggestions on how to fix this issue – my garage smells like gas  :banghead:

 

Thanks!

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Check to see if the float is leaking. Fluid inside? Otherwise, clean the carb and pay attention to the shutoff needle and seat. Inspect the tip of the needle for wear. No big deal, definitely not a warranty claim. Mine just started doing it and I have it on to do list. Good luck with your repair! :thumbsup: 

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There are basically two variations of the FCR. Slant and MX. You have the MX variant.

 

If you do not understand what you are doing, you are better off enlisting the help of a pro as a FCR is a precision part and easily ruined by unknowledgeable work.

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I replaced the float valve needle....but did not replace the seat o-ring - left it overnight and it still drips out of the overflow hose.

BTW, I also checked the floater for leaks - it is solid - I bench tested with fuel and warm water.

 

I moved to the petcock - there was a small but consistent drip from it when you remove the hose on the on/res position.  I went ahead and replace the two washers - the smiley face and the oring - Yamaha part numbers per another thread -

3AJ-24534-01

3AC-24523-00

 

When tested the petcock, these is still a drip in the ON/RES position...

 

Any help will be appreciated.  How does the o-ring seat look like and how do you take that out?

Edited by ratu

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hi all,

 

i hate to ressurect an old thread.  i have an fcr39 on my motarded '00 suzuki dr650.  it never leaked w/the clarke tank and the suzuki petcock, which has a 2nd hose going to the top of the carb, even w/the petcock in the "on" position.  i suspect this is the suzuki vacuum set-up that keeps anything from leaking.

 

this past weekend, i installed a new acerbis tank w/its single-hose petcock - no vaccum line.  i plugged the hose going to the top of the carb and hooked up the normal gas feed.  now, it leaks like crazy, even when running.  (unless the petcock is off.)  if the bottom carb drain orifice is plugged, it starts leaking at the top of the carb.  (haven't tried that when running.)  what did i do wrong?  should i have not pluged that top hose on the carb?

 

i know i can reinstall the original petcock in the new tank, but i don't want to go cutting a new hole into the acerbis tank if i don't have to.

 

thanks in advance,

 

doug s.

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Clean and polish your needle valve assembly, or check to see i the float pin is loose

thanks; it seems a bit of debris was clogging the float walve, introduced w/the new tank install.  shutting off the tank petcock, then opening the carb drain all the way to lower the float, then opening the tank petcock w/the float in its lowest position (and the float walve at its most open position) allowed the gas to wash the debris out of the walve.  now everything's good; thanks!

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It can be:

  • Debris on the float needle valve
  • Cracked float eedle valve seat oring
  • Float set to high
  • Damaged drain screw from overtightening

 

 

i have a really annoying leak out of fcr overflow tube, ive had the carb off everyday this week, sometimes more than once..

 

replaced float, needle valve, seat o-ring...

 

when taking a close look just now inspecting the needle valve and when it closes.. im set at 9.5mm.. and closer i move to 9.0 - 8.75mm the valve seems to not be closing.. 

and it seemed to be working best (fully closing valve) around 9.8mm...

 

should i just set it to 8.75 and test and see if leak is gone, even though it seems to not be fully closing?? 

is 9.5-9.8 too high, and possibly encouraging an overflow leak??

Edited by 707LAKE

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1 mm is not enough to loose sleep over. Most specs give a range of 2 or 3 mm. It does slightly affect jetting (a higher float causes it to be slightly richer) but 99.99% of the world would never notice. Set it so it does not leak and be done with it.

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1 mm is not enough to loose sleep over. Most specs give a range of 2 or 3 mm. It does slightly affect jetting (a higher float causes it to be slightly richer) but 99.99% of the world would never notice. Set it so it does not leak and be done with it.

thanks.. i had the drzFCR in/out 3 times yesterday..

set spec to 9.1

installed the 2nd/extra set of valve seat/o ring/ neelde

 

im confused about what mm itll leak around.. will it leak only at the bigger side of spec (closer to 10mm)??? and not the small side(8mm)

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When setting the float, the carb should be held at a 45 degree angle. The float tab, just touch (not depressing) the spring loaded pin on the float needle.

 

You are measuring from the float to the carb body. A larger number means the float is sitting lower in the float bowl and therefore will cut off fuel sooner. A smaller number means the float will sit higher in the float bowl and be more prone to leaking and running richer.

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When setting the float, the carb should be held at a 45 degree angle. The float tab, just touch (not depressing) the spring loaded pin on the float needle.

 

You are measuring from the float to the carb body. A larger number means the float is sitting lower in the float bowl and therefore will cut off fuel sooner. A smaller number means the float will sit higher in the float bowl and be more prone to leaking and running richer.

hmmm im leaking anywhere i set it from 8.75-9.8mm

measuring correctly as described

 

and i installed a brand new jetsrus valve seat, oring, needle valve.. i even replaced them all twice, and it changes nothing

same leaking carb and cutting out issues

 

no kink in fuel line

tiny hole on clarke gas cap is wide open vented

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Set it to 10mm.

You are over analyzing this and making it a much bigger deal than it has to be.

lol.. but it leaks at 10mm or 9.8 or 9.5 or 9 or 8.75

i had to swap carbs to get the leak to stop..but im still getting the cutting out symptoms

 

:lol: i guess asking detailed questions about how small items work is over analyzing and too much of a big deal to answer

how is a gas leak that wont stop, no matter what float height, and trying to understand the float measurment, over analyzing?  :lol:

 

heres a new thread i just made about the complete issue im having..

http://www.thumpertalk.com/topic/1188237-fcr-cutting-out-tried-spare-fcr-same-symptoms/

Edited by 707LAKE

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