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Discussion Starter #1
Good Evening.

So this afternoon while riding the bike home from work I thought that something wasn't quite right, as every time I backed off the throttle to slow down for a bend it felt like rear wheel was skipping, almost like in gravel or something. Anyway, when I got home I wasn't happy with the way it felt so I stuck it up in the abba stand to get the rear off the ground so I could give it a good wobble to make sure all was well. Unfortunately there was a lot of play in the wheel but even worse I could see that the back side of the break disc had been rubbing against the calliper hanger. Upon closer inspection and to my total horror I discovered that the wheel nut on the sprocket side was really loose, I mean it only took about 4-5turns and it was off!!!!! It looks like the locating pin was not correctly seated and that is how it has worked loose.

Now, as for as I am aware the only person to have been anywhere near the rear end of my bike since I bought it was the asshat, so called, mechanic that changed my tyres for me prior to my trip to the Isle of Man Classic TT. I know he was messing about because of all the hassle I had trying to get him to accept that it was a 55mm socket he needed. So I am wondering if he made a utter arse of it and it has gradually worked loose. I am hoping to take apart the whole rear axle over the next few days to inspect the damage, I will follow up with pics of what I find.

What I am wondering is what are the chances the the rear hub is goosed, or could it just be the loose nut that has allowed some play in the axle resulting in the the rotor rubbing in the inside.??? Also I wonder how much come back I have on the mechanic that potentially caused this as it has taken so long to manifest.??

More importantly I could have bloody died!!
 

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I am left wondering why a Mechanic would touch the Sprocket Side nut during a tire change.

There have been cases of that side nut backing off and loosening as things where in the hub assembly.

Torque the nut to spec and check your play in the hub.
 

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Discussion Starter #3
I also wondered why he wold be messing about at that side, but he also couldn't work out the size of socket he needed, even after he was told by myself and another garage that it was 55mm. Trust me when I say he will never see my custom again!! He is just a little local mechanic I was pointed to my a friend that uses him for his bike. never again!

I did tighten up the nut and the play certainly got less, but I have lost my adapter to make the 55mm socket fit my socket set so can't set the correct torque. Have one ordered so hopefully tomorrow.
 

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My advice is remove the hub,check for damage.
Service the hub if there is no damage and replace the disc caliper bracket.
Buy yourself the correct wheel nut tool.
A standard socket is not correct because the nuts are tapered.
 

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Discussion Starter #5
Thats was my thinking also, I am looking to replace the chain and sprockets anyway. so may as well get them done at the same time while everything is apart.
 

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Discussion Starter #8
thanks, i tried to find as close a match to the specs in the manual as I could, but often not all the information is presented.
 

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?

My vote......
the 3810-2RS died, allowing the axle to go left into the caliper mount and making the sprocket nut seem loose

If the sprocket nut was loose, and the bearing good the axle/wheel assembly will go right away from the caliper mount

A complete disassembly and inspection will tell you what's wrong
 

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Discussion Starter #10
Would I be right in thinking that 3810-2RS refers to the bearing inside the hub unit? I am not familiar with that part number. I had wondered if the spacer and gone allowing the wheel move. But as you say a complete deconstruction will hopefully yield the answer. I hope to get started this evening if the rain holds off.
 

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thanks, i tried to find as close a match to the specs in the manual as I could, but often not all the information is presented.
It's all there, just not all in the places you'd expect.......

like some of the torque specs.....

:wink2:
 

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Discussion Starter #12
I am looking for a little bit of clarification in exactly what bearing there are inside the hub.
I have been reading this article that illustrates a rebuild of a hub unit (from AN F4). It in the author describes that you require 1x Bearing 3810 2RS , 1x Bearing HK5520 and 2x Seals MBR55X63X5A. But when I looked on the exploded diagram on Star Twin it look like there are in fact 2x Bearing HK5520. Is this just down to the difference between the F4 and B4 or is only replacing one side of the hub assembly?

Also does anyone know if BSL in Wolverhampton is still on the go. I don't seem to be able find a website for them.

Thanks
 

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It is the difference between >'10 or <'10.

The hub changed in 2010 to include the extra bearing.
 

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Discussion Starter #14
Ah I see. Now that I read this I think I remember hearing this before.

So if the hub does turn out to be beyond a simple refurb I should be looking to have it replaced with the newer version?

Thanks
 

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If you go to the newer hub, you also have to change the axle....

I'd go Mitchy Hub.
 

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Discussion Starter #16
I did not know that about the Axle. Guess it'll be the Mitchy Hub then. will that be a direct swap or are there other mods required? I will see what the status of the existing kit is like and take it from there.

Thanks Again
 

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@Calcifur: The Mitch Hub is a bullet-proof direct swap. You can use your current axle.
 

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I hope You don't need a new hub.
But there is also the Design Corse Hub as a replacement, which is a pretty decent hub too, for only 403 GBP available in the UK.
If You can fetch a >2010 axle on eBay for little money than is the >2010 MV Agusta hub also to get for a decent price, beware the stepped washer.
And Yes, Mitchy's hub is a great piece, but costs with 585 Euro on eBay the most.
Not to make any product look bad but to unveil the whole picture of options.
BTW I have the >2010 MV Agusta Kit in my F4 and Mitchy's Hub in my Brutale.
 

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I did not know that about the Axle. Guess it'll be the Mitchy Hub then. will that be a direct swap or are there other mods required? I will see what the status of the existing kit is like and take it from there.

Thanks Again
gotojoe (Joe) member on this forum stocks my hubs and lives in Ireland which is close to you.Message Joe and he can give you an exact price and whatever advice you need.Joe is a top guy and knows MV's inside out.
Don't buy one of my hubs off EBay because the price is inflated to cover their high commission.
 
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