|Posted on Monday, September 25, 2017 - 11:34 am: ||
Just reporting in to help anyone else who might be having trouble with backfiring into the intake manifold, bike won't idle, runs well but won't idle, intake leak, PROBLEMS.
So after 2 sets of HD intake seals and 1 set of James seals I discovered my problem. An air leak through the throttle plate shaft inside the throttle body. To find this I stretched a 2 inch piece of bicycle tube over the intake and zip tied it on, then zip tied that to a piece of pipe (roll the end over to make it stronger). On the other end of the pipe I attached another section of bicycle tube with the valve on it then closed the other end of the tube by folding it over and over itself. Spray the intake manifold, the tps sensor and the fuel injectors with a dish washing liquid water mix. Then pump up the tube and look for bubbles.( It would be a lot easier with an air compressor). On mine, with just a bicycle pump, bubbles came shooting out between the TPS and throttle body. Luckily I had a spare throttle body and swapped them over. The bike now runs better than i ever remember it running. I guess this leak was getting worse, slowly over time until recently when it would just stall out when idling. Anyway, if you've changed your intake seals multiple times and you still have a leak, you may want to try this.
If your wondering why the piece of pipe is necessary in the above set up, its because it was impossible to stretch the tube over the intake. A bigger tube might make it possible.