MK3 Primary chaincase cover

click · May 13, 2012

Hi,

I've decided to replace the two bushes and the oil seal in my primary chaincase cover.

Any tips on how to get these out?

I've been using an electric heat gun on the alloy surrounding the bushes but they don't want to budge. One of them is very small & is in a blind hole so you can't get at it from the other side.

The oil seal is also not budging.

I don't want to damage the casing, so any advise on how to get these items out of the casing.

Many Thanks

Kevin

L.A.B. · May 13, 2012

click said:
I've been using an electric heat gun on the alloy surrounding the bushes but they don't want to budge. One of them is very small & is in a blind hole so you can get at it from the other side.

Did you mean "can not get at it from the other side" (the cross-shaft bush)?

I cut a thread in the cross-shaft bush and then extract it using the thread.

The other bush and seals should just press out?

Using a heat gun on such a large lump of alloy is often ineffective, a blowtorch is better.

click · May 13, 2012

Hi L.A.B.,

Sorry!, should be can't, I've changed the original post.

Thanks for the advice.

Kevin

regental · May 13, 2012

If you watch the Mick Hemmings gearbox strip/rebuild video, he gets blind bushes ie. kickstart shaft out with a tap that is worked in & then you've something to pull on.

click · May 16, 2012

Hi Lads,

Decided to chicken out & give the cover to a lad who I trust to work on classic bikes, he has his own Norton Cafe racer and is normally ultra reliable.

Unfortunately when he was putting in the bigger bush he cracked the sidewall of the hole in two places!!! :evil:

Thought it might still be OK but when I put the shaft in, the bush is moving so the cover is scrap!!

Anybody out there have a good used primary cover for a MK3 ES?

Was hoping to go for a nice spin this weekend :cry:

Kevin

shrugger · May 16, 2012

Can't be welded back together?

click · May 16, 2012

shrugger said:
Can't be welded back together?

I was thinking about this but:

1. You need a really good welder who has experience working with 'british' alloy (tends to be difficult to weld due to the 'quality' of the alloy). I've had experience with this on my Triumph

2. If you got it welded, you then need to get the hole + the inner weld machined.

By the time I'd add 1 & 2 together cost wise + the time it would take I think I'd be better off getting a good used cover.

I'm trying to get a quick fix so I can get the bike back on the road ASAP.

I'll take a few pics of the damage & see what you guys think!

Kevin

click · May 16, 2012

Some pics of the damage:

L.A.B. · May 16, 2012

Easily repaired with Lumiweld or HTS-2000

http://www.aluminiumrods.co.uk/

http://www.frost.co.uk/automotive-weldi ... tAodXW9plA

shrugger · May 16, 2012

finding them isn't hard. Finding one you'd put on your Bike...

Several on ebay.

click · May 16, 2012

L.A.B. said:
Easily repaired with Lumiweld or HTS-2000

http://www.aluminiumrods.co.uk/

http://www.frost.co.uk/automotive-weldi ... tAodXW9plA

Thanks L.A.B.,

My concern is that the bush is loose in the hole now, if the crack is welded, the bush will still be loose. I think the bush did not go in straight & pushed out the sidewall.

I might use this cover as a project and see if I can repair it myself.

In the meantime I need to get another cover.

Kevin

click · May 16, 2012

shrugger said:
finding them isn't hard. Finding one you'd put on your Bike...

Several on ebay.

I know what you mean!

I don't see any MK3 covers on Ebay at the moment? A few MK2's but no MK3's. Just in case I missed something would you be so kind as to send me a link.

Thanks

Kevin

shrugger · May 16, 2012

I like HTS-2000. Be great if they sold it in smaller packs though.

Used it to repair some minor cracks in my Triumphs primary cover.

L.A.B. · May 16, 2012

click said:
My concern is that the bush is loose in the hole now, if the crack is welded, the bush will still be loose.

OK, but Lumiweld or HTS-2000 isn't "welding". It takes a little practise to get used to, as it's more like brazing or soldering than welding.

If the bush is removed, then the cracks could be closed up and then the repair carried out. I would be inclined to fit a strengthening 'collar' or perhaps build up the area all around the face of the boss with Lumi/HTS.

dynodave · May 16, 2012

click said:
Some pics of the damage:

Been there done that. welded and then remachined. I had to make custom tooling to hold the case at the correct angle for remachineing the bush bore. Lot of work...but then they don't give those away and probably half of the ones on ebay will be cracked also....

click · May 16, 2012

dynodave said:
click said:

Some pics of the damage:

Click to expand...

Been there done that. welded and then remachined. I had to make custom tooling to hold the case at the correct angle for remachineing the bush bore. Lot of work...but then they don't give those away and probably half of the ones on ebay will be cracked also....

Thanks for the reply. As I said earlier it looks like this cover will become a 'project' in the meantime I want to use my Norton

I'm thinking about a new cover, Andover Norton have them listed for £195+vat :shock:

I found another supplier who has them for 165euro inc vat, the chap who did the damage has offered to replace the cover with a new one. I don't expect him to pay for a new cover but I'll ask for a contribution towards the cost.

In a stange way I'm actually looking forward to having a go at repairing the cover :mrgreen:

79x100 · May 16, 2012

I can think of a couple of bodges for this non-critical area that would probably let you have a summer's riding before doing a proper fix but I'm not sure that I want to get a reputation for that sort of thing....and don't anyone dare mention 'Jubilee clips' ....

bwolfie · May 16, 2012

I would machine an aluminum sleeve to press over the outside of the boss. then use a set screw or two to retain it. It would be a nice permanent non welding/ machining a bulky cover fix.

click · May 17, 2012

Hi Lads,

I appreciate all the helpful suggestions. I will tackle the cover at some stage.

I don't have any 'fancy' workshop facilities, just basic wrenching access so any machining or making of parts would have to be farmed out which could get expensive!

I'll see what I can do & keep you guys posted.

In the meantime I'll just need to flex some plastic & source another cover, I doubt if I'll purchase used unless I know the individual & they can vouch the cover is in mint condition, Ebay is off my shopping list!!

More anon

Kevin

MK3 Primary chaincase cover

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L.A.B.

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