bobert_FSO wrote on 07/28/14 at 12:13:04:


I think you've left something out...

If the petcock fails open, the shutoff seal has failed or there is something holding the valve open allowing gas to flow.  You're now dependent on the float valve to stem the tide.

Or the diaphragm has failed allowing gas to leak into the vac line and directly into the intake bypassing the float valve.  This will also leak while running and cause an over rich condition.

busterboy wrote on 07/28/14 at 13:55:19:


Yup, I've tried removing the vacuum line, capping it off, and running on prime.  The results were the same.

Today in the mail I received my new needle and seat.  I took the carb apart yet again and checked, everything was clean internally with no debris found.  I changed out the needle/seat and started the bike on the PRI position.  Im waiting yet for my Raptor petcock to arrive, so I have the vacuum tube pulled off/bypassed.

The bike started a little hard but did fire, and then ran great!  I made it much farther than previous runs up and down my sub division.  I actually thought it was totally fixed until I tried a full throttle blast in 1st gear.  I popped and then started to stumble as if it was either starving of fuel or flooding.  I pulled in the garage and felt I could have forced it to stay running if I kept half throttle, but releasing the throttle to the idle position and it quit.  I wasn't able to get it to re start.  

One major difference now is that I tried pulling the little rubber cap/plug that's at the bottom of the air box, and to my surprise, there was not a drip of fluid that came out.  Previously, the airbox was filling with a oil/gas mixture.

The black drain tube that sticks out about 3-4 inches under the bike was however full of a fuel/oil mixture again though.  

What exactly is this tube and what purpose does it have?  Do I still have a flooding issue even though the air box was dry?  Or is it possible the petcock is jacked up that even in the PRI position the bike wasn't getting fuel?  Not sure where to go from here.

Also, I tried testing my floats by filling a small plastic container with fuel.  I dipped the bottom of the carb into the fuel until the floats closed the float needle.  I would say the fuel had to get about 1/4in to maybe 1/2in from the base of the carb where the bowl mounts in order to close the needle.

Aaron

Did happen to check the filters on the petcock inside the tank? It wouldn't have anything to do with the gas in the air box but it might explain the fuel starvation. Just a thought.

I believe the black tube that sits about 3in under the bike with a plug in it is referred to as a huff tube.  What is the reason for this and what does it do?

I've been chasing what I thought was a flooding issue for a bit.  The airbox and this tube kept filling up with a oil/fuel mixture.  I've changed out needle/seat on the carb and the bike ran much longer/better.  After a full throttle run in 1st gear it started to stutter, pop, and shut off again.  

This time however the airbox was not flooded with this mixture, but the huff tube still was full again.

So what exactly is the purpose of this tube and what would cause it to continue to fill up with a oil/fuel mixture?

Thanks
Aaron

Bump...
3 threads have been combined into one,.. in order to consolidate the pertinent info about this ongoing problem...
Sorry for any confusion this has caused... in the long run, it will be easier to troubleshoot this way...
Serow

As long as you have this fuel problem,.. it will collect in the crankcase and filter box... the collecting is a symptom, not the problem...
The problem, is in the petcock vacuum line, or.. inside the floatbowl, i.e., needle, seat, floats, float level, mechanics of the float hinge movement...

Ride and test as little as possible until this gets fixed... because it is contaminating your oil...
Concentrate your efforts in the float and petcock area...
Best I can advise you at this point...