FCR Carb Dirt

[KXcam22]

I was changing my needle setting and was shocked to see that the under side of the top cover on my FCR carb was poluted with dirt after 20hrs from new.  Is this normal?  I can't tell where it came from and the cover oring was clean.  Any ideas. Cam.

[don46]

I've had the carb off my 07 and never noticed and foreign debris in the slide area. thinking about it there are only a couple of entry points to get to the top of the slide, either the cap gasket or the shaft coming from the throttle cam. neither seems likely, oh yeah I forgot the throttle position sensor.

[kaw rider]

throttle cable

[hughes]

http://7602racing.com/catalog_Yamaha.php

It's time for these

http://www.brpmoto.com/product_info.php?cPath=45_287_699&products_id=1914

[maddoggy]

at first i was thinking that there was no way that dirty air would be flowing through the vent tubes. i was thinking that the intake air would be following the path of least resistance theory which would mean that 100% of intake air would flow through the airbox. then i got to thinking about a time my atv wouldn't run right at higher rpm's. i found that some of the vent tubes were plugged up on the carb. after i replaced the vent tubes the issue went away. i've assumed that the issue was that the carb wasn't venting properly,  but now i am wondering if it was not allowing the suction that the carb was wanting. i have my doubts but one never knows. those filters that hughes suggested may be a good idea. they certainly can't hurt.

[hughes]

I have found dirt in my vent lines on my YZ250. The engine is down for complete rebuild at this time. Those filters will be installed before first start up of new engine.

[BDI]

Thats one hell of an idea It will be interesting to see how much crap accumilates in the filters and which ones get dirty first.

[hughes]

Here is a easy solution using fuel filters. Cam.

You think those will stop the very fine/dust particles?? Maybe after a few rides back flush the filters and see what you catch on a white paper towel. Those fuel filters are alot cheaper.

[DoldGuy]

Cam,
During the old Moto Days we would route the vent tubes to the airbox and slice the ends of the hoses at a 45 degree angle to help prevent them from clogging. Just my 2 pennies if it helps.

[hughes]

Those fuel filters are rated at 75 microns.  As far as I can tell engine vacuum leaks into the chamber over the slide which then draws air up the vent hoses that vent that chamber.  Cam.

I would feel better with a oiled foam filter type system. Some guys are using the canister that your 35mm film comes in.

[hughes]

Where did you find those filters??

[hughes]

What kind of filter element inside?? I got a R/C hobby shop close to my work.

[Motorrad]

Hughes,
  I got them at a hobby shop that sells the gas powerd RC race cars.  They had quite a few. Cam.

Warning from someone that runs one of the largest rc websites on the net. They have stainless steel screen in them that is FAMOUS for comming appart and trashing rc motors.

[hughes]

I like the idea of removing the screen and just replace with oiled foam from an old filter. I might just head over to the hobby shop this week.