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View Full Version : Carb death please advise!



10-29-2002, 09:23 PM
This all started with my trying to adjust my stock 250SX carb. The pilot screw was seized and the head broke off - I took it to work strapped to a mill and drilled it as large as I could - the prick would not come out and snapped the dinky housing hub off instead of removing the screw. So I got an Ebay carb that sat in bad gas. I dremeled the pressed in starter jet and float seat out of the junker to put in the Ebay carb. I removed every jet, cleaned all passages of the Ebay carb. Compressed air - CRC carb cleaner, Q tips until I felt it was spotless. Replaced all the jets, tubes etc. Popped it in and tried it. There is No gas is at my cylinder with the choke on? The starter jet circuit is the only one I could not remove without ruining it so I left it but, it seems spotless? What on earth can I check? Is the starter circuit the only one responsible during cold starts? What else can I do? Thanks- :D

350Xrider
10-29-2002, 09:47 PM
I wouldn't use q-tips, the little fibers that come off of them can be just enough to partially block a carb or needle valve from working properly, this is not your case, but I just thought I'd say that anyway. Are you getting fuel into the carb? It sounds like to me that you may have bent the float during the transplant from the old carb causing it to close off the needle valve thus no fuel getting through. I'd almost guarantee that your float needs set.

10-29-2002, 10:00 PM
Thanks, but no there is pleny of gas in the bowl. Held the throttle wide open and choked and NO gas in plug? As far as the Q tip - I agree but how else do you clean an oriface? Ya gotta rub something on the walls or it won't come clean. I'm talking the housing passages with ALL jets removed and thoroughly cleaned afterewards prior to reinstalling the jets. ??????

ATC350X 85
10-29-2002, 10:38 PM
Use a toothbrush.

Mobular
10-30-2002, 12:45 AM
Soak the body in carb cleaner overnight, and use compressed air to blow the passages out...

10-30-2002, 06:27 PM
Toothbrushes are great for the outside but .200 diameter jet holes needed my Q or a pipe clnr. Did having the air clnr off when I tried this stop the intake from sucking in the fuel? What is responsible during initial startup fo fuel? Starter jet circuit? I had fuel in the bowl - why didn't opening the throttle let fuel through the main jet into the cylinder?? As I said fuel got in the bowl, I checked the jet installation again and they seem to go in one way? Any body got a better diagrahm than a Clymer book? On alot of carbs the choke closes off the air by a butterfly valve, on the SX the choke - on raises a small brass cylinder and a needle how does this acomplish that same rich fuel effect? This is so simple yet I can't figure it out :? This carb could win a show it's so clean, no other visible damage, no intake leaks etc. Whats up??????? :(