Vibes and fuel consumption

[BigCat]

Hi hope anyone can help with the following.

Last few weeks my 2003 rockster has developed slightly more-than-usual vibes and my fuel consumption is now down to ~24 mpg! For the rest it runs ok actually. I had 12K mile service done by BMW just a few months ago, assume they did the valve clearances. I checked the carb balance with a Twinmax and it looks spot on. What else could cause the vibes and bad mpg? or should i suspect the valve job that BMW did (or did not) do?
cheers
Karl

[grwrockster]

Just in case (see the misfire post I started recently - it's a few below this) - have your checked your primary stick coils?

My bike (although seemingly running ok to begin with cruising 2-up under 5k revs) started being noticeably more vibey. Then, when I tried to accellerate to test the response, it had lost power at the top end.

I then noticed that the idle was more lumpy. Doing checks highlighted that the right primary stick coil wasn't working properly (the secondary spark plugs on the twinspark models mean that you don't lose the cylinder's output altogether, but it does have a large effect on performance/efficiency).

Once diagnosed - I still had to ride it another 100 miles home. While I didn't notice a huge loss of mpg, it did use more fuel (through being less efficient I suppose).

Of course - it may be something else. But it's worth considering perhaps.

[grwrockster]

Oh yes - I thought of something else.... check that the throttle cables are both cleanly seated in the holders where the adjusters are for setting the TB balance. When taking the tank off they can be dislodged. This of course throws your TB balance right off, and it runs badly. If it is this, then simply seating them properly (and making sure there's no grit or anything stuck in the groove the cable inner runs in on the TB to operate the throttles) and all should return to normal.

Hopefully it's something pretty minor and peripheral - I'd suspect something like the things I've mentioned before anything serious.

Good luck!

[riceburner]

Stick coils.

buy a new pair.

HTH.

[BigCat]

Stick coils was indeed the obvious one so i put 2 new ones in but problem persists.. vibey over 3000 rpm (a bit more throaty sounding as well) and very poor mpg. Don't think there is much power loss.
I'll check the carb balance again, but last week it was ok. Guess i'll wait for some better weather and do the valve clearances (i don't have a garage).
Any other obvious thing i could have missed?

[spoon]

Anymore info on this?