OK so I bought an 2009 with 1000 miles. The guy had fitted a moose jet kit (155 main / adjustable needle) also fitted was a FMF power bomb with a Supertrapp slip on. He had also hacked a portion of the air box of.
The bike ran fine, but was sucking down the fuel (38 to the gallon). I purchased this as a commuter so I was looking for far better gas mileage.
To gain the fuel mileage I have put everything that was moded back to stock. Original complete exhaust and muffler, replaced main jet with Kawasaki recommended 145 main and 40 pilot, stock none adjustable needle and new plug. Now I am getting about 52 miles per gallon.
HERES THE PROBLEM. When the bike is between about 4000-5000 rpm I get a very slight stutter. If I get up to my normal cruising speed of between 65 and 70 on the interstate it just will not run smooth. It is not major but just enough to annoy me. If I accelerate up to 80 it does not do it but as soon as you ease the throttle back to cruise, it starts again. You also feel a slight stutter when accelerating hard in most gears but seems to be the worst at between 4000 and 5000 rpm.
The only thing that I have not put back to stock is the big hole in the air box (could that be the issue?) It will also give an occasional chuff out of the muffler if you coast down to a slow speed in a high gear without shifting down.
Anyone got any suggestions?
One other thing I noticed is that when I replaced the needle, I noticed that the slide diaphragm seemed to have swollen just a little as in order to get it to seat in the grove I had to use grease (kind of like an o-ring that refuses to sit in the groove due to swelling.
It is not the gas cap vent as I have tried running with gas cap open to no avail.
Thanks again for any suggestions.
The bike ran fine, but was sucking down the fuel (38 to the gallon). I purchased this as a commuter so I was looking for far better gas mileage.
To gain the fuel mileage I have put everything that was moded back to stock. Original complete exhaust and muffler, replaced main jet with Kawasaki recommended 145 main and 40 pilot, stock none adjustable needle and new plug. Now I am getting about 52 miles per gallon.
HERES THE PROBLEM. When the bike is between about 4000-5000 rpm I get a very slight stutter. If I get up to my normal cruising speed of between 65 and 70 on the interstate it just will not run smooth. It is not major but just enough to annoy me. If I accelerate up to 80 it does not do it but as soon as you ease the throttle back to cruise, it starts again. You also feel a slight stutter when accelerating hard in most gears but seems to be the worst at between 4000 and 5000 rpm.
The only thing that I have not put back to stock is the big hole in the air box (could that be the issue?) It will also give an occasional chuff out of the muffler if you coast down to a slow speed in a high gear without shifting down.
Anyone got any suggestions?
One other thing I noticed is that when I replaced the needle, I noticed that the slide diaphragm seemed to have swollen just a little as in order to get it to seat in the grove I had to use grease (kind of like an o-ring that refuses to sit in the groove due to swelling.
It is not the gas cap vent as I have tried running with gas cap open to no avail.
Thanks again for any suggestions.