I helped my friend core the pipes on his honda 919 and afterwards the bike smells awful. It kind of smells like gas and oil mixed (like its running rich perhaps?). Don't know if anyone has had a similar experience but any ideas on how he could possibly fix it? A power commander to make the bike run leaner was the one thing i thought might work. Any other ideas or thoughts?
Oh and we already changed his plugs, drained his gas tank, and put a new air filter on the bike and none of these things helped. The bike isn't burning any oil (that we can notice) but the smell out the tailpipes kind of smells like gas and oil mixed (???) its really weird. Its really strong though he can't ride to work at the hospital and see patients smelling like he rolled around in organic solvents.
On paper at least, coring the pipes should make it run leaner, so adding a Power Commander to make it even more leaner won't help (on paper).
Here is my guess at what's going on. Since it's a four cylinder it's a safe bet that it runs at higher RPM's than your average Duc. The cam timing probably has more overlap to run well at higher RPM's and may have depended on Honda's tuning of the exhaust system to provide correct backpressure and pressure pulses at certain rev's. By coring it you've undone Honda's engineering and with lowered exhaust backpressure at lower RPM's excess unburned fuel mix is blowing right through the exhaust valves. Just a guess though and if all else fails it may be worthwhile to find some ebay standard mufflers and put them back on to see what happens. I don't think you can easily put the toothpaste back in the tube by trying to recore the ones he has?
The way i understand it, a bike will emit an odor of fuel when it is running LEAN, not rich.
When the bike is lean, there is not enough fuel in the compressed mixture to achieve a complete burn. Thus, some unburned fuel remains after the spark plug tries to ignite the lean mixture. This unburned fuel (which isn't going to appear as a liquid, but rather vaporous) is then sucked out through the exhaust valve(s) and into your exhaust pipes. This then results in an exhaust that reeks of gas. If you're real unlucky, this unburned fuel will ignite itself at random due to the heat of the pipes, and you'll have yourself some unexpected explosions... more commonly referred to as BACKFIRING. Ka-Pow.