Chain suddenly rubbing rear tire

[sam000lee]

Hi all,

I am a new owner of a 1981 GS450L. I've been riding it around for the past couple of weeks and have put about 350 miles on it. Now today I was out and all of a sudden noticed smooth periodic bumps while I was cruising. I pulled over and noticed that the left edge of the rear tire has grooves in it from rubbing against the chain and was warm and sticky from the rubber melting. I have all the work receipts from the past two owners and the rear tire was installed about 3000 miles/4 years ago.

I had noticed that the chain (which is new as of February) had been a little loose since I bought it. But I have since asked the PO (who I trust) who said that he hadn't noticed and had never had any issues with it.

The wheel seems to be spinning straight and true and doesn't seem loose or like it has any side to side movement. Also the clearance on the right side of the tire with the frame is minimal (less than an inch) so I don't think that its somehow just out of alignment otherwise the other side would have more clearance.

The chain is touching the tire at rest no matter the position of the wheel.

Any suggestions/tips are much appreciated!

[sam000lee]

Oh and I should explicitly state that I am almost certain that this was not happening last time I rode it and may not have been happening when I set out this afternoon.

[Agemax]

check the chain adjusting marks on the rear axle to see if the wheel has moved. also check sprocket(front and rear) for tightness, wheel and swing arm bearings

[greg78gs750]

tire pressure? too big a tire installed?

[sam000lee]

I checked the wheel adjustment marks and the wheel has not moved. Also I don't think it is tire pressure since then wouldn't the tire be less wide?

I'm going to properly adjust the chain tension and then re-evaluate.

[Agemax]

something must have happened for it to start doing this.
the chain wont suddenly start rubbing your tyre for no reason.

[bccap]

I'm trying to visualize this. Isn't the tire inside the swing arm and the chain outside ?I can see it rubbing against the swing arm, but the chain ?

http://www.boulevardsuzuki.com/fiche_section_detail.asp?section=92443&category=Motorcycles&make=SUZUKI&year=1980&fveh=2097

[Crankthat]

Keep in mind that even though the chain adjustments might be on even lines the marks are not always even.
Also that if the axle is not torqued to specs that the adjustments only pulls on axle.
Without the torque of the motor pushing on the chain everything may seem ok with just a look.
This is a serious problem that needs to be addressed as the chain might hop off the sprocket and catch on the sprocket retaining nuts locking up the rear tire, this is most likley to happen while making a turn as the added weight will loosen it up even more.
No matter what you find to be the culprit I would recommend loosing the chain enough to take it off the rear sprocket and turn by hand while making sure each link has free movement.
The links will most likely bind from being tweaked and you may need to buy a new chain and sprockets.
Will also recommend checking your sprockets for excess grooving (the dips the chain sits in will be misshaped the curve on one side going into the teeth will be different then the other.
And also check the top section of the teeth for any scores, just feel them for sharp marks from chain digging in at a bad angel and possible hopping.

[sam000lee]

Ok thanks all - I'll take another look at it tomorrow after I've gone through the chain/sprockets and maybe update with some pictures that might clarify.

[stetracer]

I'm trying to visualize this. Isn't the tire inside the swing arm and the chain outside ?I can see it rubbing against the swing arm, but the chain ?

http://www.boulevardsuzuki.com/fiche...1980&fveh=2097

nope your wrong

[OLDENUFF]

The hash marks on the adjusters aren't always square. My bike was acting a little loose so I aligned it using the string method. It now drives like a dream. The alignment marks are out by 1/2 a notch.

[sam000lee]

Oh the string string method sounds good to me - I just did a rough realignment and tightened the chain a little (it was far too loose) and the tire is no longer actively rubbing on the chain. However I think that if the chain hadn't already nibbled on the side of the tire there would still be a clearance issue.

I noticed that (ignoring how straight the wheel was) to keep the left side of the tire from touching the chain the right side of the tire was dangerously close to touching the swingarm.

Man I wish I had a picture of the chain/tire gap before this happened or at least before I noticed it happened. Anybody else with a GS450L notice whether this gap is especially close on their bike?

[JEEPRUSTY]

I think you have a severely worn chain.
Is there a great deal of lateral play in the chain?

[Agemax]

there is a possibility that the frame or swing arm is bent, caused by a previous accident.

[pete]

What size rear tyre is on the back? On mine, I have a 110/90-18 but apparently a 120/90-18 will fit but will have limited clearance which is why I stuck with the 110.

Maybe it's just that it's too wide? The parts fiche says 4.60S16 for yours... not sure how that converts to metric measurements though?

From what I can see this should be compatible with 120/80-16, 110/90-16, or 120/90-16. I would imagine if you had a 130 on there or something it would potentially cause issues or at least make it so that being the slightest bit out of alignment will cause rubbing.