Smaller Tire?

I bought a xj750 maxim a couple weak ago, and the guy I bought it from had recently put new tires on. I just noticed that the rear tire is rubbing against the drive shaft, it has worn down the sidewall on the tire. I really cant figure out why its rubbing, it seams like its aligned and everything. So I was thinking about maybe putting a smaller tire. Right now I have a 130/90 16 which is what is supposed to be on there.Would it be unsafe to put a 120/90 on it?

 

I noticed the same thing on a project bike I picked up recently. The tire was rubbing slightly on the drive side and under close scrutiny looked off-centre. It was a 130 also, which is the right size, so I wasn't sure what the problem was... Until I took the wheel off and discovered that there was a spacer missing that fits inside the drive hub unit thing. I had another one from different bike that I fitted in and it seemed to solve the problem.

I believe it's part no. 42 in the diagram below.

 

I already checked the diagram and I'm not missing anything. unless I just need a bigger spacer which I would be afraid to do because then only a small part of teeth on the gears would be touching

 

what brand of tire is it (130/90-16)? I've noticed that the profile of tires will vary from one brand to the next. Some brands may be wider but flat, others may be more rounded and skinnier. A lot of the lower end tires (i.e. - Cheng Shin, IRC, Duro) tend to flatten and widen out as they age. I've seen Dunlops do it too, but it's usually an 8-12 year old tire. The D404 my dad put on his 700 has plenty of clearance on the driveshaft, but the old Dunlop Qualifier was close to touching.

 

may be the PO swapped a left and right spacer??

 

I took the bike to a shop and the guy said that the only thing that I could do would be to put a smaller tire on. the tire that's on it now is a big 130 so he recommends that I put a dunlop on, which should give it plenty of clearance