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Chain loosening, slipping rear hub?


courtuk

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My friend's VFR chain keeps becoming loose, literally after a few miles of riding. Adjusted the sag, torqued the eccentric hub(?) pinch bolt correctly. I have worked on my VFR and know how to do this. The chain is in good condition, I can't fathom anything else causing the chain to become very loose that soon. Has anyone else had this issue? Could grease on the hub cause it to slip like that? I've only had experience of mine and I've never removed it or touched it, and it adjusts and pinchs just fine.

 

Currently they took it to a mechanic because I wasn't around for a while to check it and they aren't mechanically minded. Just wondering what the cause/price to fix could be.

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Strange haven't ever had that happen. Perhaps some oil contamination may have gotten in. You could try loosening the pinch bolt off and spray some solvent like brake cleaner spray into the split near the pinch bolt, work the ecentric back and forth, hopefully this might clean out any crud and make the clamping better.

Have never needed to torque the pinch bolt, just use a single hex socket and wrench, very firmly tightened, never had issues.

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9 minutes ago, Grum said:

Strange haven't ever had that happen. Perhaps some oil contamination may have gotten in. You could try loosening the pinch bolt off and spray some solvent like brake cleaner spray into the split near the pinch bolt, work the ecentric back and forth, hopefully this might clean out any crud and make the clamping better.

Have never needed to torque the pinch bolt, just use a single hex socket and wrench, very firmly tightened, never had issues.

I'm afraid of stripping threads so I go by manual for most torques, 74nm. I'll update here if I hear anything.

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Check to see if the Axle rest at the 6 "O" clock position (Sweet Spot) which
affords the greatest ride height... rotate the cassette forward and the axle
rest towards the 9 "0" clock position which affords less ride height...
rotate the cassette backwards and the axle rest towards to 3 "0" Clock
position which affords less ride height not to mention possible slippage...

gallery_3131_51_13087.jpg

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Based on what BLS is stating. If the chain has too many links or is badly stretched then the ecentric bearing holder will be towards the 3 O'clock position, not ideal.

Confirm the Chain Length. Count the number of chain side plates, for a 110 link chain you should count 55 side plates inclusive of the master link.

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I'm not sure which gen VFR we're talking about here, but it may be helpful to point out that the RC36 (3rd and 4th gens) have a different axle orientation than portrayed by BLS above.

 

"Normal" for an RC36 is for the axle to be at the 12-o'clock position, rather than the 6-o'clock position.  Indeed, this is why I was able to raise the rear ride height on my 3rd gen ~40mm by "flipping the eccentric" the other way.  I think the 5th and 6th gens are the opposite (so, like the RC45 depicted above).

 

Chains which do not stay "in adjustment" are usually in the late stages of life.

 

Ciao,

 

JZH

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Whilst we're on the subject, what's best practice for maintaining a smooth and free hub (once bolt undone, of course)? Dismantle, clean off the crud and grease it? Or leave it dry?

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3 hours ago, JZH said:

Chains which do not stay "in adjustment" are usually in the late stages of life.

 

Yes, was chain measured on each of these adjustments?

Paint little mark on hub with nail-polish to see if it slipped?

 

Logically, if hub did not move, only way extra slack can develop is due to chain wearing out.

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8 hours ago, Skids said:

Whilst we're on the subject, what's best practice for maintaining a smooth and free hub (once bolt undone, of course)? Dismantle, clean off the crud and grease it? Or leave it dry?

 

Honda doesn't specify grease on the cassette for a smooth operation in the swingarm so I prefer to leave it dry...

 

AxleBearingCare (3).jpg

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22 hours ago, courtuk said:

My friend's VFR chain keeps becoming loose, literally after a few miles of riding.

Third or fourth gen I reckon.

Could be dirt that sits in the middle between the cassette and swingarm. The dirt may prevent the swingarm from clamping the cassette in the right place (on the outer sides)

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If the washer/hose holder is not trapped between the bolt and the swngarm, the bolt can bottom out in the thread without putting full clamping force on the eccentric. Or so I've read. 

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54 minutes ago, Terry said:

If the washer/hose holder is not trapped between the bolt and the swngarm, the bolt can bottom out in the thread without putting full clamping force on the eccentric. Or so I've read. 

Interesting and good point you raise Terry.

Just had a look at my 8gen and the pinch bolt thread is all the way through, just can't remember or find anything in the Service Manual as to the 6gen being or not being the same.

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6th gen pinch bolt hole in swingarm is threaded completely through

Paint marks on the adjuster and the swingarm to see if it's slipping, or the chain is about done dealin69872593a6edf386550180c98f4b3f9c.jpg

Sent from my SM-N950U using Tapatalk



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2 hours ago, Terry said:

Yes but does the shoulder of the bolt bottom out somewhere in the bore hole?

Think you could be right on the money here Terry. Absolutely needs checking that the washer/hose holder is fitted under the bolt head.

 

Removed the pinch bolt from my 8gen. The upper section of the bolt hole is fully unthreaded, lower section is fully threaded.

Took some measurements. When fully tightened there will be 4mm between the bolt shoulder and lower threaded section of the swingarm.

If the two 1mm washers under the bolt head weren't there then you'd only have 2mm clearance, fairly marginal. Hope this is making sense?

So if on the 6gen the washer/hose holder was missing, you might bottom out the bolt and not achieve maximum tightness on the bearing holder.

 

 

20211021_171229.jpg

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You guys are so good... looking forward to OP confirming which option it is, but i bet you've nailed it

 

I had the washer/hose-holder "ring" snap off last year... glad I went to Honda and replaced.  My first thought was just to remove it, I wasn't worried about the brake lines moving... but I would not have even considered bolt length & threading and the potential of not having enough clamping pressure without it

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21 minutes ago, jstehman said:

Did you measure the shoulder width vs thread width on the bolt?

 

 

No, because what would be the benefit of that?

The shoulder is at least the thread outer diameter. So the bolt cannot be tightened beyond its thread length, if the bolt shoulder hits the swingarm thread then thats the end, it can't be tightened any further. Sorry if I'm missing something here!

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34 minutes ago, Grum said:

No, but what would be the benefit of that?

The shoulder is at least the thread outer diameter. So the bolt cannot be tightened beyond its thread length, if the bolt shoulder hits the  swingarm thread then thats the end, it can't be tightened any further.

Ha!  I meant length :facepalm:

And I missed the post with the measurements

Tapatalk locked me out of this for some reason and the last thing I read was about the bolt bottoming out

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Hi all, to those asking it is a 6th Gen VTEC, my friend is picking up the bike today and we'll see what the garage has done... I'm pretty sure I would have noticed the brake line holder piece missing but this is a very good point! I'll post an update when she has the bike back and if the chain becomes loose... it was checked by another garage already and the chain they stated was in good condition. 

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