Cylinder Head Removal / Install

click · Jul 31, 2012

Hi Lads,

Question:

Composite or Copper head gasket for my 920?

I was curious about the indents in the composite gasket I have. One of the, as I said, seems quite oil soaked from one of the recesses for the cylinder barrel bolts. To my untrained eyes it looks like a weak point which could let go?

Question 2: Is oil under pressure behind these recessed cylinder barrel bolts?

Question 3: I'm aware of the dental floss trick using a copper gasket, what type of sealant is recommended for copper and composite cylinder head gaskets?

Thanks

Kevin

Hobot · Jul 31, 2012

Kevin, Push rods in factory heads put me in my place and I had to ask this spring for tricks here. IIRC, the intake p-rod goes up first, then the exhaust rod fights ya. When it finally does go in, with some resistance, I never really know what I did to finally get past the hang up, ugh. Its erks me no end when I can't learn by my errors. Don't have video going as may reveal involuntary word usage. I ended up with a spare standard head when Combat one got lost in processing for over a year. Heads likely to need servicing sooner than bottom end so while one being used up the other can be built up then no long down time except mood of chief 'mechanic' on hand. I was laughted at and taunted for paying 450 for serviced head, told way too much - back in early 2000 on other lists. Ebay head turned out to be key reason I've totally lost it on Ms Peel deal.

click · Jul 31, 2012

Cleaned as much as I could with scrapers / brake cleaner, then out came the Dremmel, used a very fine wire brush. Finished it off with a brass wire brush + cleaned it off with WD40.

I kept the shop vac going while scraping / dremmel'ing to ensure no crud/wire went anywhere it shouldn't.

Is there any harm in cleaning up the mating surface of the barrels? Seems to be a thin layer of gasket left + a few ridges from the edge of the gasket.

Kevin

Bernhard · Jul 31, 2012

click said:
Cleaned as much as I could with scrapers / brake cleaner, then out came the Dremmel, used a very fine wire brush. Finished it off with a brass wire brush + cleaned it off with WD40.

I kept the shop vac going while scraping / dremmel'ing to ensure no crud/wire went anywhere it shouldn't.

Is there any harm in cleaning up the mating surface of the barrels? Seems to be a thin layer of gasket left + a few ridges from the edge of the gasket.

Kevin

Without using a Dremmel, you want it 100% clean! Gently use a flat emery cloth & Try using paint thinners or Acetone to remove the goo.

click · Jul 31, 2012

Hi Bernhard,

Message received loud & clear, no Dremmel on the mating surface!

Thanks

Kevin

pete.v · Jul 31, 2012

click said:
Hi Lads,

Question:

Composite or Copper head gasket for my 920?

I was curious about the indents in the composite gasket I have. One of the, as I said, seems quite oil soaked from one of the recesses for the cylinder barrel bolts. To my untrained eyes it looks like a weak point which could let go?

Question 2: Is oil under pressure behind these recessed cylinder barrel bolts?

Question 3: I'm away of the dental floss trick using a copper gasket, what type of sealant is recommended for copper and composite cylinder head gaskets?

Thanks

Kevin

1. I vote for copper. I am faithful to copper head gaskets because they are faithful to me. In your case and by looking at your old composite and the evidence of blow by in those critical areas, I would say copper is your only "real" choice.

2. I do not think there is oil pressure there, what you see is the inadiquate seal capbilities of your old composite head gasket. You simply have no room for error here.

3. I use Permatex high temp copper coat spray. I never use a composite cylinder head gasket and don't know what is the right sealer if any.

Hobot · Jul 31, 2012

2. I do not think there is oil pressure there, what you see is the inadiquate seal capbilities of your old composite head gasket. You simply have no room for error here.

There is oil draining down in the push rod tunnels and also the oil drain hole so its possible the blow be evidence went both ways, ie: some pressure into crank case and some back inside on the inhales. I will never put another major Norton seam together w/o cotton, silk or dental floss back up, regardless of the style gasket or none at all.

pete.v · Jul 31, 2012

hobot said:
2. I do not think there is oil pressure there, what you see is the inadiquate seal capbilities of your old composite head gasket. You simply have no room for error here.

Click to expand...

There is oil draining down in the push rod tunnels and also the oil drain hole so its possible the blow be evidence went both ways, ie: some pressure into crank case and some back inside on the inhales. I will never put another major Norton seam together w/o cotton, silk or dental floss back up, regardless of the style gasket or none at all.

I see this particular situation as a maintenance bad dream. Not really a nightmare but the frequency required to keep things tight, sealed, and running to the effectiveness that it was designed for is much greater than a regular motor. I might think that the frequency of maintanance would depend and your particular skills and on how hard you ride.

In no way am I implying that the 920 is a bad thing, only a litte needy.

I might also think the 920 would inherently beg to be pushed. Not literally, but through the throttle, although the former may be unfortunately all to true. Do not get me wrong here, no bad juju intended.

pete.v · Jul 31, 2012

Is it just my perverse nature or are there strong similarities in these two pics?

click · Jul 31, 2012

You have a twisted mind :mrgreen:

Although there are LH and RH parts in both pics

Hobot · Jul 31, 2012

Pairs of rounded expanses boys like to see exposed now and then.

stockie2 · Aug 1, 2012

Click/Kevin,

On your 920 I am sure I saw a post in here about improving the the block deck surface, where the allen head bolt recesses are. You can make up some alloy buttons, that sit on to of the allen head bolts and take up the counter bore, naturally they need to be adjusted to be absolutely flush with the deck of the barrel. This will improve the sealing properties of whichever gasket you use. Oh and I would recommend replacing the allen head bolts, on your monster, they are possibly already stretched?
A good tip on making sure the push rods are correctly seated on the followers, just before you re fit the head, pour some oil down the tunnels, then when you have the head on you can feel suction on the push rods when you try to lift them, if they are correctly seated. Bent push rods are the other option, ask me how I know. I highly recommend the XS breather to cure oil leaks around the front of the head from the tunnels.

Best Richard

click · Aug 1, 2012

stockie2 said:
Click/Kevin,

On your 920 I am sure I saw a post in here about improving the the block deck surface, where the allen head bolt recesses are. You can make up some alloy buttons, that sit on to of the allen head bolts and take up the counter bore, naturally they need to be adjusted to be absolutely flush with the deck of the barrel. This will improve the sealing properties of whichever gasket you use. Oh and I would recommend replacing the allen head bolts, on your monster, they are possibly already stretched?
A good tip on making sure the push rods are correctly seated on the followers, just before you re fit the head, pour some oil down the tunnels, then when you have the head on you can feel suction on the push rods when you try to lift them, if they are correctly seated. Bent push rods are the other option, ask me how I know. I highly recommend the XS breather to cure oil leaks around the front of the head from the tunnels.

Best Richard

Hi Richard,

The alloy buttons were mentioned earlier, I think Ludwig made up a set for himself.

I'm not removing the barrels so the allen head bolts will not be disturbed.

Thanks for the tip re: oil in the pushrod tubes, with all the fantastic advice I've been given on this forum I think the head will just 'float' on

I already have the XS breather installed, great mod.

Hopefully the head will be finished late next week ready for install :shock:

Many Thanks

Kevin

click · Aug 4, 2012

Hi Lads,

Small update.

I chickened out & sent my cylinder head to Les Patterson of the Cylinder Head Shop. He did a T100P head for me at least 10 years ago & did a great job.

Have some bits coming over from RGM, got a copper 920 gasket so I'll see how this works out.

If all the planets align I should have everything by the end of next week.

More Anon

Kevin

beng · Aug 5, 2012

Heinz Kegler drilled holes in the top of his cylinder head where the tops of the push-rod pairs pointed, tapped them and put threaded plugs in. He removed and installed the push-rods through those holes with the head installed on the engine.

click · Aug 5, 2012

beng said:
Heinz Kegler drilled holes in the top of his cylinder head where the tops of the push-rod pairs pointed, tapped them and put threaded plugs in. He removed and installed the push-rods through those holes with the head installed on the engine.

Hi beng,

That's really thinking outside the box. I just can't help think it will just create more places where you can get oil leaks!! or you could adapt the idea & instead of just installing plugs you could install breather take off points? Two birds with one stone type of thing!

It is a great idea & would make installing the head a lot less hassle, I just can see myself drilling holes in the head.

Thanks for the pic but I can see the plugs, was it suppose to show them? Very interesting oil feed setup to the head.

All the best

Kevin

click · Aug 7, 2012

Small update:

Got my delivery from RGM today, it was posted on Friday, this is a new record for me from the UK fantastic service.

Head was inspected yesterday, all good but needs valves & guides, hopefully this will be finished Thursday.

Kevin

Keith1069 · Aug 7, 2012

Head was inspected yesterday, all good but needs valves & guides, hopefully this will be finished Thursday.

Len is a great guy but he does have a habit of 'improving' things, ie. doing work that wasn't asked for. As an example he did my seats a few years ago just as he was moving to Ireland and it took forever but despite his lack of time he still managed to 'work' my exhaust ports which I'd not asked him to do. No damage was done but the head already had big enough ports (too big really) and I didn't want it messed with any further. There are a few people who won't let him near their parts! Hope it goes OK. BTW the seat work was very good and in 18,000 mile I've not reseated the valves.

click · Aug 7, 2012

Keith1069 said:
Head was inspected yesterday, all good but needs valves & guides, hopefully this will be finished Thursday.

Click to expand...

Len is a great guy but he does have a habit of 'improving' things, ie. doing work that wasn't asked for. As an example he did my seats a few years ago just as he was moving to Ireland and it took forever but despite his lack of time he still managed to 'work' my exhaust ports which I'd not asked him to do. No damage was done but the head already had big enough ports (too big really) and I didn't want it messed with any further. There are a few people who won't let him near their parts! Hope it goes OK. BTW the seat work was very good and in 18,000 mile I've not reseated the valves.

Hi Keith,

Thanks for the heads up. I've heard similar stories about Len. I've given him strict instructions not to 'improve' the head other than replace worn parts!!

Kevin

click · Aug 18, 2012

Got my cylinderhead back from Len, all nice & clean.

Work seems fine, I suppose I won't know until I fit & run. I'll start the refit tomorrow once I check all the surfaces are flat.

Some pics:

Some very mild porting done on the exhaust ports, more like cleaning up some of the casting marks.

Cylinder Head Removal / Install

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