Clicking/vibration felt on freeway

[thorn14]

I know diagnosis of these issues is difficult online. I'll try my best to describe what I feel and what I've done so far.

I can feel a distinct but somewhat subtle clicking somewhat like a knock or sharp bump through my handlebars when riding down the freeway. It happens around 4k rpm over 30mph on light throttle. That's the only way I can really feel it over the vibration of the engine. I've pulled in the clutch and can feel it coasting as well so I'm assuming it's suspension based. It doesn't seem to be affected by engine speed and the clicks feel like they are ALMOST evenly spaced in feel, but not quite.

This started with no maintenance or changes a week after I got a tire plug. So I realize that's a possibility and have a new tire coming that I'll swap out.

I changed rear wheel bearings yesterday as one side was frozen and it's still there. Steering head doesn't seem to have any slop in it, but I'm going to replace the bearing at some point anyway soon, maybe even now just to be sure.

Aside from bearings, I'm considering forks and shock as a last resort to inspect. 749 dark forks that were rebuilt after unknown miles earlier this year. If I touch the caps while going down the road I feel every click magnified. I've never done this but I have a feeling the aluminum and suspended fluid and parts probably react to whatever vibration I feel. I can't recreate anything while bouncing on the bike though so I'm at a loss.

So check tire, bearings, and lastly suspension?

[SpikeC]

 30mph on the freeway?
Sounds like the tire to me. Lift the front and spin it and you may see a bump where the tire was damaged.

[thorn14]

Really it's 30-60 mph is where I can feel it as it's too slow under that and freeway vibration and road quality mask it over that speed.

The rear tire was the one that punctured. I can't tell with the tire mounted anything amiss, and it was just off center tread. But it also started a week after I got it repaired (300 miles). I was going to swap the tire out to see if it helps this weekend, and if not, I have a spare incase I hit more debris.

[Howie]

The tire is a good possibility, but meanwhile inspect the chain for tight links.

[thorn14]

Good call on the chain. I checked the links and they were all fine. So I almost gave up.

Girlfriend's dad thought maybe the front sprocket was missing some teeth, instead, the sprocket retainer plate was missing all its teeth. Damn thing slid right off. 

Will be replacing ASAP.

[Rudemouthsky]

the sprocket retainer plate was missing all its teeth. Damn thing slid right off. 

Dodged you a bullet right thurrr! wowz.

[skurvy]

... instead, the sprocket retainer plate was missing all its teeth. Damn thing slid right off. 

Will be replacing ASAP.

Like this?:


Check for damage to the splines on the shaft too. If they are worn, they will eat up any new retaining plates you put on and will only last a couple thousand miles at a time, trust me I know.

Check this thread:
http://www.ducatimonsterforum.org/index.php?topic=65098.msg1199924#msg1199924

[thorn14]

Yeah, I'm still getting the noise so now I'll be checking both front sprocket and shaft.

Did you experience any noise or just notice the plate wearing down?

Also, thanks for the link, I KNEW I saw a thread talking about the plates but I couldn't figure the right search words to find it.

[skurvy]

Did you experience any noise or just notice the plate wearing down?

I noticed the chain noise when rolling the bike backwards (motor off), into a parking spot. I thought it was just a loose chain so I made the appropriate adjustment. But when the noise came back within a couple days, I knew something was up so I took a closer look at the front sprocket. In my case I didn't notice any vibrations or abnormal sounds when moving forward.

[thorn14]

So I looked into it just now.

Here are some pictures.





The front sprocket that was on could "wiggle" a whole bunch which I believe allowed the scoring and grinding to occur on the shaft. I just replaced with an old sprocket and it noticeably does not "wiggle" half as much.

I'm hoping that it'll cut down on the plate damage, but the output shaft definitely has damage at the outside surface the plate rests against.

Test ride tomorrow, but it doesn't make any noise while spun on the rear stand.

[skurvy]

thorn14 - hopefully that shaft isn't too far gone. I just updated the other thread with pics of how I got it fixed, (sorry mods if it's cross posting and bumping an old thread). I don't think I had any damage to the outside surface, the part that "retains" the plate, I just had damage to the inboard splines.

[thorn14]

I'm hoping so too. I still get clicking but I've got a front sprocket with bent teeth and the old chain and rear sprocket. I've got a fresh front rear and chain coming so I'm saving judgement until then.

My shaft spline damage is on the opposite side unfortunately,  so I'm not quite sure what can be done if that is the cause of my click.

I'll know better next week. Thanks for the picture update!

[skurvy]

My shaft spline damage is on the opposite side unfortunately,  so I'm not quite sure what can be done if that is the cause of my click.

Maybe check with member clubhousemotorsports, in the other thread they said:

"Why not have a local machine shop make you a new plate that attaches via the screw hole in the end of the output shaft? You could have them make screw holes to locate the sprocket to the plate and then the plate would attach at the end of the shaft. We used to see race bikes with the sprocket held on this way."

The machine shop that made my spacer said they could also try to fab a bracket/plate that attached to the end of the shaft as suggested so I guess it's not uncommon to do it that way. I already had an old sprocket handy so I just told him to make the spacer. In any case I hope it works out for you, this kind of fix can be frustrating.  

[Speeddog]

You'll need to use a shouldered spacer under the bolt that goes in the end of the shaft.

And a bit of clearance between the hole in the plate and the shouldered spacer.

[oldndumb]

Interesting.
Wonder if there would be much demand for a product like this?