1996 VFR 750 RC36 - Rear Tire Lateral Play

I bought a project 1996 VFR 750 RC36 last year. It's got 97 000km on the clock and running beautifully.*I've been fixing it while I ride it. She's always felt a little sloppy to me compared to my low km 86 which has had extensive work done. I attributed this sloppy feeling in a corner with a mis-sized rear tire (180 on 5.0" rim) and a worn head bearing that has some noticeable notches*in it.

Yesterday I went out for a ride with a mate and from 30ft back he flagged me down and said that under braking into a corner he noticed lateral play in the rear tire "like the tire caught a tar snake." I said, how bad was it really like a mm? He said, "I could see it from 30ft back!"

I rode my 86 rc24*a while back without one of the spacers on the rear axel. Opps! Now THAT was lateral play and I could feel it. The 96*doesn't feel at all like that to me while I'm riding it however I can feel the bike flexing? at the rear when there are hard momentum changes while in a corner, which rarely ever happens and never on purpose.*

I put her up on the center stand last night and without anyone else supporting the bike I couldn't notice any discernible movement, though I'm no master tech.

Before I just go out and start throwing parts at this thing I was wondering if some experienced VFR riders could give me a nudge on what all could be going on to experience this lateral play.

Thanks!

 

Use the centrestand to get the wheel up and try moving it with hands at 9 and 3 o'clock..........after you check that the wheel nuts are torqued properly At that mileage your rear eccentric bearings may be shot, and a loose wheel hub would be a clue. :eek-new:

 

Thanks. I'll give that a check asap.

Is there any possibility that the rear shock or other worn pieces could cause the tire to push out toward the muffler under suspension compression? Like the bottom of the tire moving toward the muffler and the top of the tire away from it. Like \ under compression.

The reason I'm wondering is because I cut my muffler down from 18" to 9" and a while back I noticed the bolt that attaches the muffler to the passenger foot rests was missing it's nut. It only came to my attention as there were tiny gouge marks on my rim near the hub of the rim at a similar location to where my 9" muffler stops. At that time I assumed the muffler had move towards the rim and caused contact. Now with the possibility of lateral movement I'm wondering if the rim (rather than the muffler) moved the distance.

I cannot recreate contact between the muffler and the rim under suspension compression while the bike is stationary.

I can take pictures if my explanation isn't clear.

 

What he said, squirrel beat me to it...

 

The only things that would allow the wheel to move to the side is either the swingarm pivot or the wheel bearing within the eccentric. It should be an easy job to feel for any sideways play with the bike on the centrestand.

 

Thanks guys. I got back out to it this morning and I can't seem to find any play in the thing. But I haven't really applied much leverage yet. I'll pull out the tq wrench and make sure everything is within spec. I guess I'll be buying a 46mm socket.

I was talking to my Dad about it today *Father's Day and all* and it occurred to me that the only time I can feel the rear end really move is under emergency situations of a particular nature, of which there have only been two thus far with this bike.

I've noticed it happen when I'm in a left turn and I have to slow quickly. During both of those corners I was really hanging off the bike and I had to rapidly decelerate and change my line. When I did that it felt like the rear end stepped out towards the muffler like the bike wanted to induce a drift. Well I mean that's kind of what I'm doing to it in the corner anyway but she slides out more than I'm telling it to.

Anyway I mentioned pictures.

Here is the damaged rim. These marks were not there last year. That looks to be a good deal of play. :0 Granted as I mentioned the muffler nut had fallen off that secures is to the rear passenger peg. I can't see how anything other than the muffler could have made contact. And no, sadly I didn't hear or feel anything out of the ordinary when it occurred.

 

Something you learn when hanging off in a corner: once you're committed to a line and hanging off, it's difficult to change your line quickly if needed; so, in the cases you cited, you may simply have over-worked the rear tire traction. Add brakes and you've seriously upset the bike's suspension, so no wonder it felt weird.

 

What air pressure do you have in the tires?

Did you throw a set of strings up and check wheel alignment? How much offset front to rear?

Is this a crash-damaged bike that was repaired (project bike)?

 

Hey, K-B, "18 'till i die",Rocketman, i've missed ye and pleased to see ye back here !!! eaceful:

 

You won't be able to feel swing arm bearings with the shock in place. Remove wheel, disconnect shock then see if you can wiggle swing arm. Bad wheel bearings would show up when on center stand.

 

Hey guys, thanks for the replies! I've been out of town for a bit so I haven't had much more time to investigate. I'm back for a bit now and recently picked up a 46mm socket. I'll pull the rear end apart and get a close up visual of what's going on.

You're right about that! This was an un-natural feeling. Something is moving it's not just a traction issue.

I have done a string wheel alignment before on a different bike. Just eye balling it this bike doesn't look out of alignment. I've never crashed it but the previous owner laid it down in some low speed corners a couple times. Those crashes twisted the forks a tad in the triple but that's since been addressed.

As for tire pressures I usually run 36-42 for daily riding and drop it a bit for track days.

Good to know. Thanks! I'll report back once I get some more info.