Vibration

DaddyStu · Crazy Courier Joined: 19 Jan 2023 Karma :

Getting some seat vibro at speed following chain adjustment. The scale reads the same both sides and the sag(?) is within suggested range.

It's not severe but my prostrate has lodged a formal complaint.

Anything else I should be checking?
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Daddystu
Zontes 125-G1 (part-ex'd). Yamaha Tracer 700.

Islander · World Chat Champion Joined: 05 Aug 2012 Karma :

Wheel alignment?

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

Front sprocket securely bolted on?

Sprocket carrier bearing in good order?
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sickpup · Old Timer Joined: 21 Apr 2004 Karma :

Check for stiff links and if your rear sprockets is actually round.

dave001 · Banned Joined: 22 Nov 2022 Karma :

bet you dint look for the tightest spot on the chain before adjusting

possible wheel is not inline.

Is it possible you knocked of a wheel weight while doing it?

sickpup · Old Timer Joined: 21 Apr 2004 Karma :

DaddyStu · Crazy Courier Joined: 19 Jan 2023 Karma :

Thanks all. Yes I checked the chain over when i relubed it so sure its not a stuck link. Not sure about the front sprocket - to check would require some disassembly so will check when i've some time.

Wheel alignment would seem the likely culprit. I was under the impression doing up the adjusters the same on both sides accounted for that. Web-search would have me using strings and tubes to check - or I could wait until the service due this month.
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Daddystu
Zontes 125-G1 (part-ex'd). Yamaha Tracer 700.

WD Forte · World Chat Champion Joined: 17 Jun 2010 Karma :

Feck all info so making guesses.

I'll assume your 'sag' is free play, but how much have you allowed it?
and how/where did you measure it?
I'm also assuming its pretty new so has low-ish miles
I'm also going to assume/guess as it is a sudden symptom,
you've just over tightened it a bit.

I'd try backing it off half a turn on each adjuster, maybe even 1 complete turn as I'm ( still) guessing the adjusters have 8mm threads and will have pitch of 1.25 to 1.5mm so wont slacken the chain very much.
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DaddyStu · Crazy Courier Joined: 19 Jan 2023 Karma :

Pete. · Super Spammer Joined: 22 Aug 2006 Karma :

Slacken off axle, loosen adjusters 1/4 turn, bash tyre forwards, re-tighten axle and ride it. If it is not the same then you had it too tight, or your carrier bearing is shot.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good Very Happy

MCN · Super Spammer Joined: 22 Jul 2015 Karma :

The rear sprocket may be out-of-round. Common thing.
You therefore need to adjust the slack in the chain to be at the the tightest position when the wheel is rotated.
If its substantial, you can watch the slack on the lower part of the chain change as the wheel rotates.

TLDR
The adjustment was checked at the slack part of rotation.
So the chain will go banjo when the slack is taken up byt the sprocket.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.