Alright so I'm not a rookie, been around the sport for 25 years but I made a huge rookie mistake.
I have an '08 450 that had a leaky float bowl (from the seal between carb body and float bowl) on Friday and I wanted to ride yesterday so I did what anyone (or so i assumed) would do in such a predicament and put some Yamabond on it for a quick fix....but it wasn't Yamabond, it was RTV and i didn't notice until it was already way too late. So fast forward to yesterday and I go to prep the bike to head out and ride. I turned the fuel petcock on and it began profusely pouring from the float's overflow hose. I turned the gas off and tore the bike down to the carb so i could inspect it. As soon as I took the float off I saw the horror which was grey jelly blobs floating around the float bowl in the fuel. So i cleaned the float out, assembled the bike and fired it up. It ran great without any bogs or hesitation so I turned it off and put it away for the night. Today I went to ride, fired the bike up and it ran great, went out on the track and boom...half a lap in and the bike bogs and dies, sounds like it ran out of gas. I went to kick it and the compression felt low, low enough that i could crank the bike by hand. I pushed the bike over to the pits and threw it up on the stand, moved the kicker with my hand for a couple kicks and then the compression came back. I got on it and tried to start it...nothing. I pulled the choke out and it fired right up, idled great and ran great at low-mid RPM's until I gave it full throttle and it stayed at mid-RPM's and then fell on it's face BUT the choke was out so i figured it was normal. I pushed the choke in and the bike idled, as soon as i gave it gas it died. I took the carb apart, the jets were clear, the throttle moved fine, i saw fuel squirt into carb when i applied the throttle so that was all good. I put the carb back together and fired it up, did the same thing, wouldn't run without choke and popped upon decel so i knew it was lean which meant plugged jet or something. When i took the carb off the next time i noticed the o-ring at the tip of the Tusk air/fuel screw fell out and was in 2 pieces. I put it all back together and haven't touched it since.
So....it lost compression after stalling, the compression came back after a few kicks but the bike won't run without a choke. I'm going to clean the carb completely tomorrow and if I have to i'll check the timing. I have to order one of those o-rings too so hopefully that's the issue and we can stop it there.
Thanks for anyones help.
Edited by SquidHunter785, July 31, 2016 - 04:51 PM.