how do you check ignition timing....why would this have changed over the winter when all I did was change plugs and coils.
It is just a good idea to check the timing in general when servicing a motorcycle. Timing sometimes "walks" just from use. Sometimes a change in the coils exacerbates the problem. A lot of time on bikes you can have several minor problems that by themselves would not be noticable but working together can cause you a real headache. Your timing could have been out all along but until this carb problem came along you might not have noticed it. To check timing you need a timing light (prefferably induction - means it clamps on to the spark plug wire). Your manual (you do have a manual don't you?) should have detailed instructions on how to set the timing. This is also how you can check if the advancer is working (by revving the bike while the lite is shining on the window).
The point is to rule things out as you work, the more things that you check and know are functioning properly the better off you are. If you are going to be stubborn about it then maybe you shouldn't be working on bikes.
So far you have ruled out an ignition problem as far as we can tell, and you are still seeing black plugs. Plus the bike has been sitting all winter (probably with no fuel stabilzer in it) which is usually how gummed up carbs happen (remember fuel is only good for 4-6 months).
At this point here is what I would do:
- Check the airbox or whatever for any obstructions. Make sure your filters are clean.
- Check that all the airbleed screws on the carbs are setup properly
- Pull the rack off, pull the float bowls out and chek to see if any of the jets are plugged. Run a wire through them just to make sure.
- Check that all the needle positions are at the same height. If you have CV carbs, use compressed air to make sure the slides are functioning as intended.
