plugs

My bike runs good most of the time, but if it sits for a couple of days the plugs on the left side will be fouled out and I have to take sand paper and clean them off. Then it runs strong again.My question is if I put something under the kick stand to make the bike sit a little straighter will it fix the problem?

Sounds like your valve guide seals are going away.

You'd do better to put the bike up on the center stand, it'd be less likely to fall over to the right if a strong wind came along...

It does sound like there is an underlying problem there with the left cylinders, maybe all but it just shows up on the left. One thing I've found is once a plug starts fouling it becomes a bit unreliable, they seem to foul easier, I suppose it's hard to get them really clean again. Second, I was having some trouble with my plugs, more from carb issues I think but I went from a "9" plug to an "8" and it really helped.

Good luck!