Open Chest Surgery....

Tornado · Dec 14, 2019

I'm going to open up the timing chest on my 850 MKII. Goals are to check/replace timing chain; pull oil pump to glass the casing sides; replace all accessible seals. Got the Intermediate Shaft locking plate:

(AN part resold by OldBritts, $30 USD)

Can't quite tell from the parts diagrams if there is seal beneath the crank pinion or just the one on the timing cover side? Hoping to avoid the need for the special puller tool to remove that pinion to change the seal (best price I could find for tool is around $70 CAD).

kommando · Dec 14, 2019

No seal on that side of the crank, there is one on the primary side but you are not going there.

Tornado · Dec 14, 2019

kommando said:
No seal on that side of the crank, there is one on the primary side but you are not going there.

Great news....I've already replaced PS crankseal last season when I'd found it to be blown apart (from wet-sump pressures) after finding oil being dumped out the primary case opening.

So I have no need for the $70 pinion puller at this time?

rvich · Dec 14, 2019

Pulling that gear is most likely not going to be necessary unless you find it has been damaged. I can't see another reason to pull it for the maintenance you have listed.

Fast Eddie · Dec 14, 2019

IMHO, given the fact that you most likely only intend to do this once, I would fit a new pump. Lapping the faces is ok, but the gears wear too.

The old girl is worth it !

NKN · Dec 15, 2019

Have a read here https://www.accessnorton.com/NortonCommando/oil-pump-testing.7314/

Tornado · Dec 15, 2019

Yes the pump condition described in other threads is what I expect to address. Bike has just gone past 13k miles, not quite half of that by me in past two seasons of owning it. Pressure gauge shows approx 10psi per 1k rpm as recommended. She will wet sump to below the tank oil sieve within 7-10 days.

cash · Dec 15, 2019

Have you got the points seal guide? It's not necessary but will make fitting the TS cover easier and reduce the chance of seal damage.

Tornado · Dec 15, 2019

cash said:
Have you got the points seal guide? It's not necessary but will make fitting the TS cover easier and reduce the chance of seal damage.

Planning to get it presently along with more bits and bobs ill be be fitting over next couple of months.

concours · Dec 16, 2019

OP, You are running an oil pressure gage, right?!

Tornado · Dec 16, 2019

concours said:
OP, You are running an oil pressure gage, right?!

Yessiree!

Open Chest Surgery....

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