Changing primary fluid

So as I am reading the manual for my '71 it says to remove the cover. No drain?
Should I replace the O ring seal on the cover?
I dont have that many miles on the new engine and this is the first go around for changing fluids.

No drain, you do need to remove the cover but that is easy once you get the footpeg bracket off. I've had my primary opened up several times, have never replaced the seal/gasket, and no leaks. FWIW many here use Type F ATF (easy to find at auto parts stores) in the primary with good results, including me both with stock and Barnett clutch plates.

yup that 's right Mike .... carefully remove side cover , you will need a long flat pan , to minimize mess .... I like to tap it with rubber mallet to get it moving .... if you are real careful you may save the large o-ring type sealing band ....I'm sure lots of folks get a good seal when putting it back on .... I always line the bottom half with gasket maker just to be sure .... type F trans goes in mine ... once you get it off do a good cleaning inside everything and make sure the groove for sealing band is good and clean and free of burrs .... sorry for rep and I see you got your answer while I was typing
Craig

I would pull the cover. It gives you a chance to have a look see at what is going on. Any swarf in the usual grunge at the bottom of the covers. How is the chain sag? Sometimes the trans can be pulled forward under hard acceleration, especially as the year your bike is only has one adjuster. This would also cause the rear chain to become tight. Bolts from primary cover to the crankcase working loose (damhik). The rubber seal usually doesn't have to be replaced. I had one that would weep, but placing a piece of butchers string under it in the inner cover gave it just enough push to seal.

My builder is using engine oil in the primary. He is trusted and good. 10/30 up to 20/50 Its worked for me so far, whats the deal with type F trans fluid?
Seems rather thin.
I think I will get a new rubber band. Im superstistious.

franko said:

I would pull the cover. It gives you a chance to have a look see at what is going on. Any swarf in the usual grunge at the bottom of the covers. How is the chain sag? Sometimes the trans can be pulled forward under hard acceleration, especially as the year your bike is only has one adjuster. This would also cause the rear chain to become tight. Bolts from primary cover to the crankcase working loose (damhik). The rubber seal usually doesn't have to be replaced. I had one that would weep, but placing a piece of butchers string under it in the inner cover gave it just enough push to seal.

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According to the law about levers, it necessarily follows that there will be more pressure applied to the rear chain than that applied to the primary chain, so that is why it is suggested you adjust your primary by winding your adjusters to loosen the primary chain to the correct looseness. This then means the rear chain cant pull the gearbox back and pull the primary chain tighter.

Dereck

MikeM said:

My builder is using engine oil in the primary. He is trusted and good. 10/30 up to 20/50 Its worked for me so far, whats the deal with type F trans fluid?
Seems rather thin.
I think I will get a new rubber band. Im superstistious.

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Motor oil is to thick and will make your clutch slip, the Norton clutch is surpose to be run dry but the primary chain needs to run in oil to keep it lubbed so running a light early Ford trans oil as they had clutch plates in the transmission and the F tranny oil was used so the plates wouldn't slip, works very well with the Norton, remember the oil in the primary is only there to spash around the primary chain, without oil the chain will die very quickly,
I learned at a very young age that nomal motor oil that the book reconmended wasn't the best and caused a lot of clutch troubles, mostly clutch slip, so started to use lighter oils in my primary to see if the clutch slipped or not, as well using nomal motor oil I found I had to pull the clutch down more to clean the plates as they got stuck together and hard to free up, no problems since I been using the early Ford F trans oil and I am still using my orginal plates after 40 years of riding my Norton.
Not sure how the newer brand of motorcycle oils that have addives added for wet clutch use would go in the primary, but I will stick with the Ford tranny oil as I do know it works great

Since owning my Norton since new I have always done everything by the book but I had a lot of clutch problems after a few years on the road mostly with clutch slipping when putting on the gas and hard to free the clutch when sitting for a few days, but that all went away after using lighter oils and now have been using the Ford tranny oil for over 5 years now, it seems to work the best.

Ashley

Hi Dereck: My Experience and thoughts is that the engine sprocket puts a forward pull on the chain wheel, this being mounted to the transmission. The adjuster for the trans is in on the timing side for this bike. As the power is applied from the motor on the primary side, this can allow the trans to cock and shift forward in the cradle under repeated HARD acceleration. I believe this became a issue as later bikes came with a adjuster on both side of the trans and after market kits are being sold. In my post, I thought I had said, it was the primary chain that became slack and the rear chain became tight as the trans had moved forward. In my experience I have had this happen.

My original post seems to have disappeared so second try:-

franko said:

I believe this became a issue as later bikes came with a adjuster on both side of the trans

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Not as far as I'm aware.

franko said:

and after market kits are being sold.

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They are intended for belt drive conversions where shaft alignment is more critical.

http://www.rgmnorton.co.uk/buy/gearbox- ... es_832.htm

Shaft alignment is just as critical for chain as it is for belt.....if you want to obtain reasonable life from a chain that is!!
One friend decades ago told me he could take the average BSA /Triumph 3 owners motor and on the dyno obtain a notocable increase in power simply by tensioning and aligning the primary chain correctly. Aligning and tensioning chains correctly was and is apparently beyond the competence of many British motor cycle owners but but it will keep the people selling new chains happy!!
Not that long ago I asked a VERY senior belt industry Gentleman as to what effect on belt life incorrect belt tension had.....His reply went something like as follows......'Ah we did testing on this subject many years ago......I can probably find and send you the results if you want but basically we found that a correctly tensioned belt had a life 3 to 4 times greater than that of an incorrectly tesioned belt'. I BET the same applies to chain.
Ever seen and examined the web pages ' Synchronous belt failure analysis guide'?? IF you run a belt BEFORE slagging off the belt manufacturers products check your failed belt against the pictures shown and determine why your belt failed......

J. M. Leadbeater said:

Aligning and tensioning chains correctly was and is apparently beyond the competence of many British motor cycle owners but but it will keep the people selling new chains happy!!

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strange, when I installed my belt primary 2 years ago the old (original) primary chain was still in great shape... perhaps my (and the PO's) incompetence was given a pass by the primary chain gods.

J. M. Leadbeater said:

Not that long ago I asked a VERY senior belt industry Gentleman...

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Yes, I too was shitting in a public stall a few weeks back and struck up a conversation with the chap in the stall next to me about belt tensions, chain defelection etc... he confirmed all the claims made by your source.