Mk 3ES outrigger plate problem (2)

[mdt-son]

Dear community,

I am having a problem joining the outrigger plate to the inner primary for my Mk3 build. Posts at the outrigger are an accumulated ~0.75 mm out to allow the outrigger plate to seat at the machined posts of the inner cover.

Both parts are preowned, but they look nice - there is no apparent sign of damages, overheating, or otherwise. Because of its robust design, I believe the inner cover to be okay. Having read a couple of verdicts in the following thread

Thread 'Mk 3ES outrigger plate problem'

Dec 30, 2018

Hi all, I'm in the process of reassembling the primary chain cases on my Mk3 ES after removing them to drop the engine far enough to pull out the rear isolastic. When I tighten up the outrigger it pushes the starter drive gear hard up against the chain tensioner plate cover to the extent that it won't turn. Before tightening there is a gap of around 16 thou between the back of drive gear (this is the one that houses the anti-backfire ball bearings) and the cover plate but that closes to zero when the outrigger is tightened up. I can't think of anything that I've done that may have caused...

• Balmain Bill
• chain tensioner electric start drive gear primary chain case
• Replies: 18
• Forum: Norton Commando Forum

I think my outrigger plate may have warped as well. When laid on a glass ceramic oven top, which is the flattest surface I know of in my household, one of the outrigger plate posts displays a gap of at least 0.1 mm, probably more. I know it's not the surface causing trouble here, but being a machined face, it may indicate distortion of the entire outrigger plate.

If there are other occurences of bad outrigger plates among owners, please speak up. Did you fit a new ourigger plate in the end, or was machining the plate and its posts successful?

- Knut

 

[L.A.B.]

The inner case and outrigger plate below are from different sources and they wouldn't fit together without some fettling but it would need to maintain the rotor to stator clearance.


Here's another outrigger that does fit the same case.

 

[mdt-son]

The inner case and outrigger plate below are from different sources and they wouldn't fit together without some fettling but it would need to maintain the rotor to stator clearance.

Here's another outrigger that does fit the same case.

Les,
Interesting find, which suggests there were different versions of the outrigger plate and probably of the chaincase as well. I have two samples of the inner cover (case, as you call it), revisions 22K4 and 29K4, and I have two outrigger plates (no revision marks, unfortunately) who fails on both covers. With no compatibilty chart, I am reluctant to ordering a new outrigger plate. Has anyone here digitized the outrigger plate and the inner cover wrt. diameter of the recess? AN won't give out any measurements probably, but I will ask anyhow.

I know NVT revised the primary chaincase at least once, giving AN a hard time in recent years. There should be final and current dimension for the machined diameters in question, to make sure the current spare parts will fit. I will post my findings as new information comes to light.

The "fettling" is elaborate, because these parts were machined in a vertical mill with a large circular cut. Finding the centers is imperative to maintaining rotor to stator clearance.

- Knut

 

[Torontonian]

Perhaps as you say it could be different runs at machinings ? Did it fit before taking apart ?
I have 2 MK3 models and both have had no issues fitting their outrigger plates .
This primary is far more complex than previous years , the manual forgot the tensioner gasket
, so be sure to fit one , 06-6570 . Never use the soft bend over tab washer on the clutch , 063459 . Omit it and use se blue Loctite . Tighten the nut to 40 lbs. , not 70 . The rotor washer 067894 should be upgraded to a Belville type one . 70 lbs. to it and blue Loctite .
Proceed .

 

[mdt-son]

Perhaps as you say it could be different runs at machinings ? Did it fit before taking apart ?

No, they are parts from dissimilar bike donors.
Thanks for your advises - they are very useful.

- Knut