Quote:
Originally Posted by Weldangrind
Quote of the day! 
Interesting plume theory. It never occurred to me that the venturi effect would work in reverse. |
The backflow thing happens with two strokes sometimes, when the piston is on the down stroke and compressing the contents of the crank case some mixture escapes before the reeds shut (or the reeds could be damaged) and if it passes the tube at speed it pulls more fuel out then gets sucked back in to the carb mouth for the next indunction cycle and helps its self to more fuel. This really screws carburation. I think boost bottles help sort this out a bit but to be honest I'm not an expert.
The thing I dont understand is why it's happening on a four stroke other than my complete guess above. The carb has had moments of doing this before too even with the short manifold. Leaky inlet valve maybe?
Didnt get to run it this w/e, our track day got cancelled!
Right where's that chocolate pie??