How to remove Needle Vavle and Seat?


29 replies to this topic
  • WR_Dave

Posted December 30, 2009 - 09:08 PM

#21

Yeah , I don't know that you can remove that type of needle seat. I may be wrong , but I would call a carb shop or James Dean to verify. I believe those seats are pressed into the body so you are back to using something to clean out the passages. Also you may get more answers and help if you didn't spread this over so many threads. JMHO -- WR Dave

  • Mrmonk7663

Posted December 30, 2009 - 10:29 PM

#22

Alright I'll make some calls then. I didn't intend for it to get spread on my cleaning thread but oh well. Thanks for all ur help.

  • WR_Dave

Posted December 31, 2009 - 07:10 AM

#23

No worries, let us know what you find out. I used to remove, clean and replace the O-ring on the needle valve seat of my old WR 426 every winter , but haven't done it to my '07, so it would be interesting to know how to change the seat. Good Luck -- WR Dave

  • Mrmonk7663

Posted December 31, 2009 - 08:18 AM

#24

So far I have been told the seat is for sure pressed in. I was told by a tech that you can heat the carb body to expand the metal and then pull the seat out. He also said u could drill a hole and punch it out then epoxy the hole...didn't quite understand where he thought u could drill. I'll make some more calls later. I don't understand because pressed in or not there is still an prong under the seat so if it fails then everyone is screwed? I find that hard to believe.

On a related note the o ring under the seat...what is it's purpose and how do u know if it's good? I'm guessing it's to stop fuel from entering the space around the valve seat...assuring that fuel enters into the seat first. I'm further guessing that with the needle installed that if u blow through the fuel inlet and no air is moved then the o ring is good but I may be totally wrong so if u can advise on this that would be great.

Thanks
mike

  • myoung

Posted December 31, 2009 - 09:20 AM

#25

Keihin uses non serviceable o-ring type gaskets to seal passages between the body parts. They're not available as a replacement part so that would lead one to figure they are meant to only last the life of the carb. If there is an o-ring under a pressed in seat, then odds are they are doing the same there. Even if you could get the seat out, you are probably not going to be able to get the gasket. I would look into that before you get determined to pull the seat.

I would say use the Q-tip trick that was suggested and do a good cleaning job on the seat without removing it. If the WD-40 doesn't get it done, then use spray carb cleaner on the Q-tip. Once you're done screwing around with the needle valve, you can start working on that pilot circuit. If this is how bad your inlet circuit is, the pilot circuit is more than likely just as big a mess and will probably lead to your next thread. :moon:

A word of advice on the spray carb cleaner. It will attack all your rubber parts and can ruin them. There's quite a few rubber parts, the bowl seal, air horn seal, fuel screw o-ring, AP diaphfam, etc. There is also a rubber seal on the slide plate and when you start the cleaning task on the pilot circuit the passage shoots right under the slide and the spray cleaner is going to hit that seal. If you don't want to remove the slide, then make sure you open the slide and stuff a rag between the slide and the pilot passage hole while cleaning.

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  • Mrmonk7663

Posted December 31, 2009 - 03:52 PM

#26

Thanks for the advice on the pilot circuit. I called zip Ty racing and they said "there isn't an oring under the valve seat per se". The more people I talk to the more it seems that yamaha has one carb diagram for all years even though there have been quite a few changes. I cleaned my seat today I'll attack the pilot circuit next. Thanks guys. And I have given up on taking the seat out lol.

  • Treebark

Posted December 31, 2009 - 04:09 PM

#27

That does not come out. Look at the link given by WR DAVE. Good reference with pics. The screen is there, just blow threw the screen to clear any debris. I have an 04 parts breakdown and I only see a needle valve available not the seat.

  • Mrmonk7663

Posted December 31, 2009 - 05:12 PM

#28

I looked at Daves picture but the carb is not the same as my carb. In that picture around the seat there are 2 screws, mine doesnt have this. My fuel inlet is different and other little things are different too. In my carb when I shine the light there is no visible fuel screen. Oh well lol it ran before great, it'll run again im sure :-) I figured out the slide removal, very easy. I checked my rubber seal on the wear plate and it looks good.

Unrelated question....I removed the TPS from the carb. Is there a special way to put it back on? only reason I ask is because on TokyoMods carb form it says DO NOT REMOVE TPS FROM CARB....so im wondering if there is a reason. I'm not sending my carb to them I just know they have been in the game a while.

Thanks. Happy New Year to everyone!!!

  • Treebark

Posted December 31, 2009 - 05:39 PM

#29

Needs to be reinstalled so it provide the correct resistance/voltage. If you have a Ohm-voltmeter you can reset it. Rough setting: would position the TPS to provide 0-2k OHMs resistance between the terminals of TPS. Have a good New Year.

  • Mrmonk7663

Posted January 01, 2010 - 06:56 AM

#30

I'm gonna be a carb expert before this is all said and done...thanks for the TPS info Treebark....i'm sure i'll bring it up again once its time to reinstall the TPS to make sure I get it right :-)




 
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