Replacing stem oil seal (2012)

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Small problem, I've been using a 7mm bolt for the spring compressor tool BUT I've been using imperial nuts, which are a loose fit but were good enough to compress the spring BUT are not good enough to compress it now (they keep slipping/stripping the thread :roll:

I'll have to wait until tomorrow to get some 7mm nuts (just forgot to get them when sourcing the bolt!)

The spring will have to be compressed a fair bit to get the collets in so I'll need good nuts to do the job :D

More Anon


Kevin
 
Well, I'm sure all of you have been on the edge of your seats waiting to hear if replacing my valve stem oil seal worked :roll:

It worked out great, big thanks to ludwig again for posting such a useful & easy to follow step by step guide.

Had a little bit of hassle getting the collets back in, which was expected, just a bit fiddly.

Bike is bolted back together and ran on the bench for 10mins and everything seems OK so far.

Just as I decided to go for a shakedown spin the heavens opened, it is Ireland :mrgreen:

Hopefully this has sorted the smoking issue from the RH exhaust, no sign of smoke on the bench but I won't count my chickens until I take it for a spin & get everything nice & hot.

Kevin
 
:evil: :evil: :evil: :evil: :evil: :evil: :evil: :evil: :evil:

Well, brought the bike for a short spin and . . . . . . still smoke from the RH exhaust?

Pretty much the same as last time , no change.

I'm going to do some basic checks again, compression test etc.

I know about blocking the oil feed to the head to see if the problem is top or bottom but I don't think I have the nerve to do this!! I can't get my mind around running the bike for even a few minutes without an oil feed going to the head!


If say it's not the rings, and the guides seem OK what else could it be?

The engine, as far as I can see, is oil tight (no leaking head gasket etc.)

Before I got my Norton it had been converted to a 920 (only 2K miles on the conversion & I've only done 1500, so 3.5K miles on the rings/bore) any issues from the conversion that could cause this?

So, any ideas what it could be?

Kevin
 
Just did a compression test:

RH 200 PSI (this is the one thats smoking)

LH 190 PSI

With these PSI readings I'm presuming I don't have a rings/bore issue.

I can see the top of the RH piston is oily & the plug is oily so oil is still getting into the combustion chamber.

The new seal might have moved/slipped off?

I'll strip the springs off again tomorrow & have a look!


Kevin
 
click said:
Just did a compression test:

RH 200 PSI (this is the one thats smoking)

LH 190 PSI

With these PSI readings I'm presuming I don't have a rings/bore issue.

I can see the top of the RH piston is oily & the plug is oily so oil is still getting into the combustion chamber.

The new seal might have moved/slipped off?

I'll strip the springs off again tomorrow & have a look!


Kevin
Click to expand...
Them is some might high numbers ya got there. What's up with that? I've not heard of such high numbers unless the rods were stretch like I did with my dads 1965 421 2+2 Pontiac one night.

The new seal might have moved/slipped off?
Click to expand...

Maybe it's being blown off from a sloppy valve guide. Something is out of wack in that general area.
 
Thanks for the reply.

I was using the ES to spin the motor over, both plugs out, with the throttle fully open. I checked my records and I did a compression test about a year ago & got 190 PSI from both sides. I'm presuming the oil in the RH pot is causing the extra bit of PSI.

The engine has a 920 conversion, not sure if this is why the PSI readings are high?

Thanks about the info. re: valve guide The valve seemed like a good fit in the guide. I'll check the seal and see if it's moved.

The really annoying thing is the bike is running great, solid tickover, starts easy, runs great, just lots of smoke at tick and when you blip the throttle!!


Kevin
 
Kevin.....as it's an 850 head, it might be worth checking if there is a crack in the head behind the guide leaking into the inlet port....a wet inlet valve might be visible too
 
Seeley920 said:
Kevin.....as it's an 850 head, it might be worth checking if there is a crack in the head behind the guide leaking into the inlet port....a wet inlet valve might be visible too
Click to expand...


I'll have a good look around when I remove the springs.

Just curious, if it is cracked, can it be repaired or is it a new/replacement head?

Thanks

Kevin
 
click said:
Seeley920 said:
Kevin.....as it's an 850 head, it might be worth checking if there is a crack in the head behind the guide leaking into the inlet port....a wet inlet valve might be visible too
Click to expand...


I'll have a good look around when I remove the springs.

Just curious, if it is cracked, can it be repaired or is it a new/replacement head?

Thanks

Kevin
Click to expand...

You might be able to see a hairline crack in the top of the inlet port. The other thought is if someone has flowed the head, sometimes they might just break through the drain hole from the head so there might be a pinhole on the right hand side which opens up when the head gets warm and can suck oil in that way....just things I've seen over the years. It's possible to have it welded up and repaired. There used to be a place called Aluweld just off Pearse St that were good at ally welding and regularly did Trump heads.
 
Seeley920 said:
click said:
Seeley920 said:
Kevin.....as it's an 850 head, it might be worth checking if there is a crack in the head behind the guide leaking into the inlet port....a wet inlet valve might be visible too
Click to expand...


I'll have a good look around when I remove the springs.

Just curious, if it is cracked, can it be repaired or is it a new/replacement head?

Thanks

Kevin
Click to expand...

You might be able to see a hairline crack in the top of the inlet port. The other thought is if someone has flowed the head, sometimes they might just break through the drain hole from the head so there might be a pinhole on the right hand side which opens up when the head gets warm and can suck oil in that way....just things I've seen over the years. It's possible to have it welded up and repaired. There used to be a place called Aluweld just off Pearse St that were good at ally welding and regularly did Trump heads.
Click to expand...

Aluweld!, brings back memories. When I got my T100 Triumph from Brendan in Trident motors over 25 years ago I had very little knowledge of how to work on motorbikes, I had to learn quickly :roll: On a number of occasions I was ham fisted with alu-casings & went to Aluweld to save the day.

Hopefully the problem I'm having is an easy fix, I'm hoping to find the seal has popped off again but I'll have a really good look around the inlet area once the springs are out.

Has anybody used these: http://www.ebay.com/itm/Manley-Valve-St ... 1372wt_933


Kevin
 
OK, sort of good news!

I had another look at the seal and it was split

Replacing stem oil seal (2012)


Brand new original seal from RGM.

Can't think of how I could have damaged this when installing unless I pushed down too hard on it when installing?

Any tips on how you install these. I'm presuming its just a push down from the top checking it has located with the grove at the top of the guide.

Makes me want to get a better quality seal like the ones I linked to above, has anybody used these on a Commando?


All I can do at the moment is fit another seal and see how it works out!


Kevin
 
OK, more pics.

I can see a line running along the side of the support wall for the rocker stud. I'm thinking its a casting line but could this be a crack. (see photos below)

Is this where cracks tend to be? Just looking for some experienced member who has seen some cracked heads, there's a joke in there somewhere about Norton owners and cracked heads but I just can't put my finger on it :mrgreen:

Around the guide everything seems OK.

Any advice appreciated


Kevin

Replacing stem oil seal (2012)


Replacing stem oil seal (2012)


Replacing stem oil seal (2012)


Replacing stem oil seal (2012)


Replacing stem oil seal (2012)
 
Hi Kevin,

The cracks I have seen tend to be from the guide hole heading rearwards, not always easy to see . I think that one you were looking at is just a casting mark. Hopefully it will just be the seal that is your problem though!
 
Hi I had the same problem, The seal came off the guide, I machined the guides and fitted Ford cosworth seals they have a steel body, never can off again.
Bruce MacGregor said:
I have used the rope trick on my Norton with out any problems. I had an intake valve seal that went up & down with the valve stem.
:wink: The tricky part is getting the valve spring compressed and not losing the valve keeper. Pack the head & intake with paper towels so that the keeper halves can not go far. Use heavy wheel bearing grease to make it easier to re install them.
Click to expand...
 
If it wasn't so discolored right along the crack, so to speak, I would say casting mark too. You better get some expert opinions. You should get it magnafluxed. With you showing 200 PSI, some sort of detonation may be eminant.

Seriously, that does not look good from here. I do not want to cause you undue alarm or grief but you better lean on the side of caution. It may be nothing but it looks like something.

I repeat, could someone chime on the that 200 psi compression number?
 
pvisseriii said:
If it wasn't so discolored right along the crack, so to speak, I would say casting mark too. You better get some expert opinions. You should get it magnafluxed. With you showing 200 PSI, some sort of detonation may be eminant.

Seriously, that does not look good from here. I do not want to cause you undue alarm or grief but you better lean on the side of caution. It may be nothing but it looks like something.

I repeat, could someone chime on the that 200 psi compression number?
Click to expand...

Thanks for the reply, I think :mrgreen: I know what you mean in terms of caution. I plan on replacing the seal again & see how it runs. My thinking is if I can get it to run wihout blowing smoke at tickover then it's not a crack. I have run the bike for 1500miles without any major issues and it had about 2000miles on it before I purchased it.

Ideally I'd like an upgraded seal but without having to machine anything (I don't ask for much!!1) I'm aware of the seal with the spring on it but again I'm looking for better than that!

The 200 PSI does seem high, as I said I'm not kicking the bike over, I'm spinning the engine on the starter for 2-3 secs.

When I install another seal I might shoot a bit of video showing how I'm doing the compression test just in case I'm making a basic mistake?

Thanks

Kevin
 
Kibblewhite make valve stem seals for Commandos. I've never had trouble with the genuine ones, but people tell me the Kibblewhite ones are better.
 
pommie john said:
Kibblewhite make valve stem seals for Commandos. I've never had trouble with the genuine ones, but people tell me the Kibblewhite ones are better.
Click to expand...


Hi,

Thanks for the info. on the Kibblewhite seals, just what I was looking for.
 
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