OK, so I went to my local salvage yard (Bent Bike for those of you in Washington State, awesome place!
). I went there to get the coils and some baffles for my pipes (they are too loud for me, now that I have about 6 months riding with them ). I went in and asked for the coils I saw last time. Different guy and I had the same discussion I had last time I was there, and I told him I had messed with the jetting the best I could get it and I am fairly sure it’s the coils. I mentioned I need baffles too, and he asked why. I said it’s too loud, and I’m running pretty well open pipes.
Long story short, he said the back pressure may be too low, and therefore the bike can’t maintain enough pressure to burn the gas efficiently, hence the missing, running unevenly and fouled plugs. The coils should work fine even slightly out of spec. If the backpressure is too low it would not only run badly, even if the coils are perfect, but I could burn up the valves, even if the plugs are showing rich.
Well, since I wanted baffles anyway, and it seemed like this may kill two birds with one stone I bought the baffles and went home – put them in yesterday, and rejetted to a stock pilot and 140 main, just in case...
Runs perfect – wow.
I mean it hasn’t missed once, balanced carbs after valve tune, etc. Just perfect. I am still fine tuning it as the mixture is showing a bit lean at 1 ¾ turns out, but that’s about it. I think we are on the right track. However given my experience thus far, I will reserve final judgment once I get a few weeks down the road, but I think it was lack of back pressure the whole time.
What has me confused thought is how many people say they are running open pipes, and jetting up 1-2 sizes, and turning their carbs out 3 turns and such. Maybe it’s each bike is different, but I’m trying to learn here too. Could it be these guys are running on borrowed time? I mean my bike ran, not well but it ran. I just wonder how many of these bikes are slowly burning up because of open pipes and the wrong jetting... it took a while for my bike to show these symptoms...
Like I said, I’m learning. I hope to make this a hobby of mine, so the more info the better. I’d love to hear anyone else’s input, experience and feedback on this.
For the time begin I am glad to be close to finished with the tuning, and can now turn my attention back to the fun part –
and customizing...
Thanks