can someone explain why an fcr carb has a two peice slide , and what function it has , i don;t understand what having a plate with a hole w/seal, on the front of the slide would accomplish. purely from a techincal stand point why is it there?

fgrote, on 14 April 2012 - 08:09 AM, said:

I am not sure either. People refer to it here as the "vacuum plate" and replacing the damn thing is around $60.00. The slide itself is $150.00. I wonder if that side of the carb gets much more wear and breaking the vacuum plate out like that has something to do with it. I doubt it would be the only reason why though. Also, if you want to replace the seal only, which Honda does not offer, you can use the following:
http://www.sudco.com/

Sudco P/N 021-726

Keihin P/N 1099-817-6000

Seal, Release Plate

The idle vacuum pulses on a four stroke single are huge. They hit the throat of the carb like a giant hammer. The rubber seal is basically a shock absorber and moderates the pulse on the idle circuits. Think of the fuel mixture like it was a wave. The engine wants it to be flat, but it asks for giant chunks. Allowing the slide to "flex" helps moderate the mixture.

Awesome mr moto....ty!

No problem. When I was cleaning my carb I about shit myself when I found what Honda wanted in order to be able to replace that seal.

Edited by mrmoto35, 14 April 2012 - 02:33 PM.

mrmoto35, on 14 April 2012 - 02:33 PM, said:

Its not 60.00 ..at the dealer its 102.00 WHAT THE FU*K , ONLINE ive found 63.00 +atleast 7.00 shipping  so your going to drop 70.00  on it......
my metal plate has some wear on it , so im scared to just buy the seal , and waist more money. when i went threw my carb i put some grease between the two ,thats probably not a good thing ,it might keep the plate stuck to the slide.?

I made the mistike of cleaning the carb with auto carb cleaner and ruined that seal.  I didn't think you could buy the seal w/out the plate.

The vacum release plate and hole also help to keep the throttle from sticking open the strong vacum of the 4t will suck hard enough on the slide that it will get stuck against the carb body.

fgrote, on 14 April 2012 - 04:03 PM, said:

NO I wouldn't grease it. The fuel will just break it down and feed it to the cumbustion chamber. How much wear? Did you get a pic of it? My 02 carb showed some wear but it still ran fine

fgrote, what part of California do you live in? You can get parts here and will call them and pay no shipping. It's Huntington Beach Honda. When I was with Honda my price on that plate was $42.00. Also, you may want to look it up using the Keihin part number. Honda is going to add their cut to the price but so is anybody else. Honda likes to take a big cut though.

http://www.hbhonda.c...2008&fveh=20243

mrmoto35, on 14 April 2012 - 04:47 PM, said:

Im In northern ca ,  the part number i need is 16037-KSE-671 , its more expensive , i'll go over to sudco and have a look , i don't have a pic.
The wear i have ,is only on the bottom of the plate on  both outside edges another thing that bothers me , is the plate is metal , the carb body its rubbing agaist is aluminum , if the plate has uneven wear , its pretty obvious the body of the carb has uneven wear too

Edited by fgrote, 14 April 2012 - 05:59 PM.

If you only need the seal for the release plate you can buy it separately from any Yamaha dealer.

fgrote, on 14 April 2012 - 05:53 PM, said:

Thats how mine looked as well. If I remember right the plate may be coated? I would highly doubt your carb body is an issue. Like I said my 02 looked like that and it ran perfect on my bike. They guy I just sold it to says it is running awesome on his bike.

Whats the issue you are having, what are the symptoms?

mrmoto35, on 14 April 2012 - 06:34 PM, said:

yes it is coated ,funny thing is  even though i bought it used ,i know it has very low hrs on it , the problem is, i have to run the mixture screw 3-3+ turns out , everything has been gone threw multipal times,and or eliminated , bike actually runs fine at that setting , i just know its not suppost to be that that far out , ive told myself to just slap some silicon on the screw and carb body to keep it from falling out and call it a day , guess the ocd kicked in , and ive been on a mission to figure it out LOL

I really didn't post this thread , so much about the problem im having , but more just for a technical reason why the slide was two peice,without going up and rereading ,the answer about so much vacume would cause the slide to stick ? how would that be possable , even if it was a one peice , the slide rides on wheels,so if the slide rides on wheels how can big blast's of air hitting the slide need a plate? im assumming the blowing back out it hits the plate ,the seal acts like a shock aborber , to help it from wearing out the carb slide and body? if thats the case you would want to replace the seal every now and then , if theres that much turbulace there?
so calling it a seal plate isnt a good word for it ,honda calls it a floating valve , it really actuates ,so in oder for it to do that you really dont want to have anygrease there as i did , that would impair it from actuating , and even if the rubber looks good it could flatten and need replaced  ?

Edited by fgrote, 15 April 2012 - 07:10 AM.

The the slide rollers have a loose fit as the slide still needs to have contact with the carb body to seal properly. The vacuum pulse of a 4-stroke can be strong enough to hold the slide stuck to the carb body. That is why almost every FCR 4-stroke bike has two throttle cables. If the slide gets stuck, you can crank the throttle closed.