Suspension link/Dogbone bearings

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nickst4
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Suspension link/Dogbone bearings

Post by nickst4 » Sat Aug 17, 2019 8:40 am

I thought I'd better transfer the subject here from General Chat, because it is rather vital.

The needle-roller bearings in my new-to-me 650 were rusty and solid such that the back wheel barely moved! Worse was the fact that the sleeves of the bearings were corroded onto the bolts, particularly on the forward end of the dogbone, which can only be accessed from one side. How this came about I don't know but in 27K miles it could have been salt, though the rest of the bike is very nice. Possibly a PO had used a pressure-washer 'under there'?

Anyway, I've had to cut through the bearing sleeve and bolt with a diamond cutter on a multi-tool to free it, and the job has taken days and not without collateral damage to the mounts on the frame. Now I need to source new bearings, sleeves, seals and bolts. Any hints on that will be appreciated, but I'm looking to make up bearings from a general supplier rather than pursue Cagiva parts.

I'll let you know how I get on, but in the meantime do give consideration to those bearings because it's a right royal pain to replace them if they go rusty and seize! :rant:

Nick

Aussiejoe
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Re: Suspension link/Dogbone bearings

Post by Aussiejoe » Sat Aug 17, 2019 1:40 pm

Seems to be a standard issue with the Raptors, my 650 carby wasn't that bad but the needle roller bearings and cages were destroyed. The bearings are very generic, any good bearing shop should be able to supply them, dimensions are: 22mm outside diameter, 16mm inside diameter and 16mm long. Bearing number is hk1616-b and you'll need 6
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You'll also need 6 seals, dimensions are: 22mm outside diamter, 16mm inside diamter, and 3mm thick. Packing everything in waterproof grease is about the only option to try and prevent this from happening. All bearings/seals for the frame/swingarm/wheels are generic bearings and should be available at any good bearing shop, this is the full collection for my bike, sizes are in the parts list.
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I have my bike disassembled at the moment and I can get you dimensions for the bushes if you know someone that can turn them up for you on a lathe, or https://www.oemmotorparts.com/oem5.asp? ... A-RAP-4_CE item number 47 and 51(3 needed, all the same) for about 20 euro each. Bolts are 10mm x 65mm(item 48).

As a side note to get the bolts to come out, lots of heat is needed. I bought a heating torch to get the bolt out of the chain guard and also used it to get those needle bearing shells out. The wishbone/dogleg/suspesnion link is alloy which has a roughly 50% higher expansion rate to steel so heating that will help get the bearings/sleeve/bolt out. Try not to heat the shock, a damp rag wrapped around the bottom of the shock and kept wet while heating the link should help to prevent putting too much heat into the shock.

Aussiejoe
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Re: Suspension link/Dogbone bearings

Post by Aussiejoe » Sun Aug 18, 2019 10:02 am

Just had a look at one of the MV Agusta websites here in Australia, and they can supply the pins you need, I suggest you try one of the dealers near you and see if they can get them. Part number is 800095057.

andybaggies
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Re: Suspension link/Dogbone bearings

Post by andybaggies » Sun Aug 18, 2019 7:07 pm

Anyway, I've had to cut through the bearing sleeve and bolt with a diamond cutter on a multi-tool to free it
Sometimes you've just gotta get medieval with 'em :x
but in the meantime do give consideration to those bearings because it's a right royal pain to replace them if they go rusty and seize!
As you know I ride all year round and will attended to them at least once a year usually just before the MOT, in March, and have never had them seize. Wheel out, all bolts out, thoroughly re-grease the bearings, thoroughly clean and re-copperslip the pins & bolt and finally thoroughly spray with ACF50.

I'm pretty sure the lack of a centre stand is the primary cause of missed maintenance.
Part number is 800095057.
Thanks for this & the other info Joe, top man.

nickst4
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Re: Suspension link/Dogbone bearings

Post by nickst4 » Sun Aug 18, 2019 8:33 pm

Yes; thanks very much Joe for your input! :thumbsup:

Looking at HK1616 bearings, I see these are also available with seals at one or both ends. Possibly this reduces the length of the needles but the extra sealing might improve longevity, especially if the standard seals were still fitted out board to protect the bearing casings. Worthwhile, do you think? Of course, the ends of the steel pins are still out there in the weather.

By the way, where do OEMparts ship from? Obviously their needle rollers are uneconomical (£20 each vs £6 from a local supplier) but the sleeves might be something I'd get from them.

Nick

andybaggies
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Re: Suspension link/Dogbone bearings

Post by andybaggies » Mon Aug 19, 2019 8:41 am

Worthwhile, do you think?
I should cocoa - two seals have gotta be better than one and as for the bit of pin sticking out ACF-50 should help with that.

Aussiejoe
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Re: Suspension link/Dogbone bearings

Post by Aussiejoe » Mon Aug 19, 2019 3:53 pm

Here to help as much as I can guys! There's a couple of issues I see as to why there is an issue with those bearings. One is the location, all the grime and crud flicked off the front wheel goes directly on that link. The other issue is that the bearing don't rotate fully, but rocks back and forth in a narrow range, roughly 1/4 or less of their full rotation, putting pressure on a small area of the rollers and cage, which I think is the main cause of the bearing failure.

I think Andy has a good idea maintaining them yearly. If you're going to re-do those bearings and pins with the intention of minimal maintenance, I'd be getting those pins made up at an engineering shop in stainless steel(I can get the dimensions if you need) and using stainless steel bolts. Pack the bearings with a waterproof grease like this (I have seen boats with in-boards motor that had the drive shaft packed with waterproof grease to stop the water coming in) https://www.boataccessoriesaustralia.co ... 400gm.aspx and possibly looking at some sort of rubber flap to prevent spray off the front wheel going onto the link.

Double seals can only help, and shorter needles shouldn't make much difference. OEM parts are in The Netherlands, they have a shipping calculator here https://www.oemmotorparts.com/ship_est.asp I've heard people mention they're expensive for freight costs, minimum 50 euro for us Aussies. That's why I suggest if you want the original part, try a MV Agusta dealer locally.

nickst4
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Re: Suspension link/Dogbone bearings

Post by nickst4 » Fri Aug 30, 2019 9:09 am

I'm told by a UK MV dealer that those bearing sleeves/pins are no longer available from the factory, so I'm hoping to flush out some old-stock ones from somewhere. I could easily turn substitutes on the lathe, but they wouldn't be hardened and ground to size like the originals and would likely suffer from the heavy load on a bearing that only moves a few degrees.

More later...

Nick

nickst4
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Re: Suspension link/Dogbone bearings

Post by nickst4 » Fri Aug 30, 2019 9:49 am

nickst4 wrote:
Fri Aug 30, 2019 9:09 am
I'm told by a UK MV dealer that those bearing sleeves/pins are no longer available from the factory...
I should have said that I've now put in an order to the OEM parts people in Holland that Joe mentioned because they still list the pins, but if they source from the factory I expect I'll get the brush-off from them too.

Nick

andybaggies
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Re: Suspension link/Dogbone bearings

Post by andybaggies » Sat Aug 31, 2019 12:51 pm

I'd be getting those pins made up at an engineering shop in stainless steel(I can get the dimensions if you need) and using stainless steel bolts
I reckon Joe's got the best idea here.... can't go wrong with stainless.

nickst4
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Re: Suspension link/Dogbone bearings

Post by nickst4 » Sat Aug 31, 2019 1:06 pm

andybaggies wrote:
Sat Aug 31, 2019 12:51 pm
I'd be getting those pins made up at an engineering shop in stainless steel(I can get the dimensions if you need) and using stainless steel bolts
I reckon Joe's got the best idea here.... can't go wrong with stainless.
Not sure you are right Andy, cos stainless is nothing like hard enough for the bearings to run on. However, I've already sourced stainless flanged bolts and nyloc nuts in fine (1.25mm pitch) thread, including a longer one for the front bearing in case the captive thread in the frame is compromised and it needs an outboard locking-nut too.

Nick

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Re: Suspension link/Dogbone bearings

Post by Aussiejoe » Sat Aug 31, 2019 2:37 pm

andybaggies wrote:
Sat Aug 31, 2019 12:51 pm
I reckon Joe's got the best idea here.... can't go wrong with stainless.
I reckon Andy has got the best idea going with stainless steel pins. The bearings will have a mild steel cage and that is the weak point, and stainless is harder than mild steel. I was a boilermaker/welder for 25 years, and if corrosion is an issue, use stainless steel.

nickst4
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Re: Suspension link/Dogbone bearings

Post by nickst4 » Sat Aug 31, 2019 2:55 pm

Joe,

By 'cage', do you mean the outer shell or the separators for the needles? I'll test my old shells but I'd be very surprised if they are untreated mild steel. At the very least, they should be case-hardened. The separators for the needles don't carry any load and are usually quite soft.

Stainless is good tough stuff generally. Not having anything better than SS bolts, I've used it as a bearing surface in handle-bar levers fitted with needle roller bearings but it does mark. The loads in our suspension must be far greater than in 'bar levers!

Nick

nickst4
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Re: Suspension link/Dogbone bearings

Post by nickst4 » Sun Sep 01, 2019 12:06 am

nickst4 wrote:
Sat Aug 31, 2019 2:55 pm
Joe,

By 'cage', do you mean the outer shell or the separators for the needles? I'll test my old shells but I'd be very surprised if they are untreated mild steel. At the very least, they should be case-hardened.

Nick
The shells of those needle bearings are dead-hard, as expected. The sleeves/pins need to be the same IMO.

Nick

nickst4
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Re: Suspension link/Dogbone bearings

Post by nickst4 » Sun Sep 01, 2019 10:15 pm

Continuing the saga, I've made contingency plans for decent bearing inner sleeves if I can't locate any OEM ones.
The originals are 16mm outer diameter, 10mm bore, and 42mm long. I've found pukka hardened sleeves 16mm OD, with 12mm bores and 20 & 22mm length. Pairing those will do nicely when they are mounted on a thin 42mm-long sleeve turned on the lathe, giving the required dead-hard bearing surfaces for the paired needle roller bearings to run on. Rather pleasing is that this will be much cheaper than the discontinued OEM sleeves, and way more affordable than getting hardened/ground sleeves made by an engineering shop.
The above sleeves ought to arrive in a few days but I'll continue to try to flush out some OEM old stock just in case.
Details to follow...

Nick

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