Is it worth persisting?

I've been away from the forum for a while - I have to admit to getting on with other things when I am not actually using or working on the bike. Anyhow, this is the bike, which some of you may remember from last year.




As soon as I finished the rebuild last winter, I hit two major snags:

Firstly, having moved to France midway through the rebuild, I assumed I could get temporary insurance using its UK documentation, as I did with our cars. It turned out that no one would even consider it, so I had to get the bike registered here as a 'Moto de Collection' - relatively easy to do, with the aid of the French Norton Owner's Club, but very costly in time.

Secondly, an old rugby injury (dislocated knee) flared up as soon as I started kicking her over and I could barely walk afterwards, let alone start her up again. Thus, stark choice - start again on a mark III, fit a starter or just give up. I had no cash, but couldn't face the prospect of selling a bike I had only ridden for 20mins. Anyhow, the God of Norton smiled down upon me and within a couple of weeks I had a tax rebate for almost exactly the cost of an Old Britts starter - I wanted an Alton because of cost and ease of fitting, but their technical department said it was not suitable for my bike!?

Apart from fitting a CNW console (and the starter and French number plates of course) the bike is as it was when I first finished the rebuild.

And now for the main reason for me making this post. There are one or two things to iron out still with the bike, but because there are a few rallies I want to go on this summer, there is one thing that concerns me the most and that is a weeping head gasket. The engine is a 920 and is using a flame ring gasket of reputable manufacture - I have used both copper and composite on my old 750, with no issues at all. The bike has covered less than 300Km and I have just completed the third round of retorqeuing, with oil leakages prior to each one - not masses, but enough to spatter the leading edges of the side panels.

I know this topic has been done to death on the forum, but I'm really looking for advice that may relate to my particular set-up - new Maney barrels and Maney stage 2 head. If something else breaks ok, but I don't want to get stuck in the mountains because of an incontinent head gasket - one of the trips I want to make is a four day, 1000Km coast to coast ride through the Pyrenees. All things being well, I should be able to get a minimum of 2000Km on the bike before this trip.

So, my question to you much wiser people out there is; should I persist with the fitted gasket and, if so, for how many miles before I give up? and, if and when I give up, what best to replace it with and are there are any tweaks I can employ to stop the seepage happening again?

Cheers, Bob

some head gaskets never seal and many need extra non norton breather help via various flapper check valve and placement> great leprechaun green

Sorry friend, I think you know the answer to your first questions but are just in denial. You know you won't want to ride that fine bike, with a fresh rebuild, while it's spitting crud on your nice paint and loosing compression all the while? Get the pain over with and feel better while you ride.

Salut Bob,

I use an annealed copper head gasket with copper wires around the pushrod and oiling tunnels as per Jim Shmidt's method, and it works great on my bike.

Hope it helps,

Laurent

Hobot. I have a CNW breather valve. Leprechaun green..... A bit harsh; it looks really good in the Charente sun!

Roadrash. I really don't know the answer, hence my question. However, I've spent a long time putting this basket case together and would love to spend my time riding rather than wrenching. I'll lift the head if I have to, but don't want to dive in unnecessarily.

Laurent. I have a vague recollection of reading about this method, but can recall no detail. I already have the gasket, would you have a link?

Cordialement, Bob

FWIW, in 2010 I had to fit new pistons to my 850. I had a stack full of 750 head gaskets and no 850 gaskets. So on with the old gasket, with an educated amount of silicone sealer on both surfaces. When tightening it up, my neighbour interrupted me for a few minutes then the head went back on with the usual cross words relating to those pushrods. When I tightened the head, the 2 studs under the exhaust ports started pulling. Fcuk. It stayed together anyway. In that time I have received 2 prizes for the most travelled in the north island to a rally. The last on being last month. 1800 miles or so. My engine is dry above the crank seal, and always has been. Its in bits at the moment after fitting a new rear main seal [ which was so hard and brittle that it broke up on removing ]. I lost the 2 nuts under t he front of the head so bought new ones, drilled them then refitted then and tie wired them, just for looks only as they don't do anything. I know it's against basic principles but, after 5 years and relatively high mileage WTFC.

I have seen lots of ways of fitting different gaskets on this forum. My way has worked. Look at the guy who used silicone to seal his primary. He couldn't get it apart easily. Bet it didn't leak. I use the same sealer everywhere on the bike.

Dereck
ps. I love the colour of your bike. Have you tried using your left leg to start it while its on the main stand. Have seen that in NZ a couple of times.

What I've run into re-using copper is after a few annealings and some blow by to nip up again they seem to get thicker-thinner sections that no amount of torque can flatten out even again. Just a few microns mind you but enough to pass oily gases. Head turning green sheen Commando but lost award points on this forum by not doing head like everyone else, except me of course. I'm going to try the thin copper wire embedding with new gasket on my current leaker thrown down to crank just to ride hard and fast w/o such a mess.

Pull the head, its not a big job a few hours and be done with the problem, put a copper gasket, annel it and put some sealent on it and should be all good, check to see that your valve cover stud aren't leaking as well as when they do it looks like the head gasket is leaking.

Nice looking Norton, you done a sweet job.

Ashley

Has this got an alloy cylinder fitted ?
Its not that heap-of-trouble 810cc (taken out to 920) version is it.
If you don't know the magic incantation, you have no hope....

Nice leprechaun green, like hobot says, very apt.

A quick check before you pull the head. I experienced similar and the culprit was actually the intake rocker cover leaking from the center nut. Oil gets sucked forward and looks like a head gasket leak. Look at the rocker cover and check for a trail of oil going downward from the single nut. If it's dry....proceed with head removal

I've had oil show on head draining down on cases then back on side covers to find a fork seal leak to fix. A Fully Fettered Commando is a wondrous worrisome thing to constantly strive for.

Are you finding any of the bolts during re-torque loose or are they all tight to spec? Not until did I get zero clicks on a torque wrench did my oil weeps stop. A leaky rear rocker cover that dripped down between the carbs had me looking for what appeared to be a head gasket leak. Hot oil has a way of findings it way to some weird places.

Scott

"Is it worth persisting?"...

No.
Give up now and walk away.

I'll try and answer without using quotes.

needing - Tried it once. Didn't turn out well!

kernel65 and others - I use the backing off before retorqueing method, but I do check the torque first. For the first two retorques, most of the bolts were below spec, but this time there was little, if any, further movement and this is what prompted my enquiry to the forum. I've had leaky rocker covers on an earlier Commando, so I took time to ensure that these were good and flat and not over tightened. As certain as I can be that they are not the culprits; pretty sure that the leak is from the front of the head gasket but, as you say, hot oil gets everywhere.

Rohan - no, it was a new Maney cylinder.

Hobot - You will have to tell me, how does everyone else do their heads?

kerinorton - Not sure I would want to use silicon unless I was in a fix. However, if it fails again, never say never - will you now continue with this method and how easy was it to get the head off? On your other point. I have used my left leg in the past (at the time I first knackered my right leg in fact) but my left knee is little better nowadays!!! Thank goodness the starter works really well.

BTW, has anyone put a good few miles on one of these starters, as I have some concerns about likely longevity of the belt system?

As fitting a new head gasket is looking a distinct possibility, and if I choose to use a sealant, would Permatex Copper Spray-A-Gasket be a suitable choice? I used this stuff for the cylinder base.

and if I choose to use a sealant, would Permatex Copper Spray-A-Gasket be a suitable choice?

Click to expand...

Works well on copper gaskets but also look up the thread around the pushrod tunnels as well.

Didn't know there was a composite gasket made for 920. Is that definitely an 82 bore item? For sure some sealant around the pushrod tunnels is a must, copper or composite. The thread method is a good one also. I've been getting oil coating both sides of the head gasket and minor weepage and after doing the rings this winter I noticed my torque wrench was well underreading was nowhere near on the 20 or 30lb specs.
I learnt that even my cheapie is adjustable against a spring balance. I can't be sure but it has probably been off by 20% + for at least two head gaskets. I used to have a feel for such things but the stupid things I do now no longer surprise me

Jim Schimdt http://www.jsmotorsport.com/ and those that make or sell the 920 cylinders have various thickness of gaskets though Jim recommends the thin copper wire superglued in place as back up before nip down, with some extra sealant of your choise just in case. My favororte is racer hi temp blue Hylomar which is sold be different companies now. I ignore torque wrenches and just go by feel short of marring the nut heads and if pulls out a stud oh well better at home than on the fly. Even the most disciplined famous torque wrench devotee's admit when pressed they too re-torque at times by feel which completely nullifies any logic to use torque wrench at all. Read the recent post of t-wrench misleading. Each re-use of nuts also increased the torque twist needed to get similar clamp force but that hardly ever mentioned or factored in setting of wrench but reported here a few seasons ago by comnoz and online references. Should come home early on first few rides to allow time to go over fasterners from cradle through bolts to head till eventually can't turn any of them w/o fear spikes of ruining the fasterner or wrench, then should stay good for 1000 miles or so a go. Never use any modern synthetic thread in seams as melts to leave voilds in sealant.

Its not the valve covers that leak mostly but the suds that the cover nuts screw on, the oil will travel up the studs and leak down the front of your motor and spray around the area of your head gasket, mine did that and I throught it was my head gasket, pull the studs out, put some good sealant around the threads will fix those leaks.

Ashley

It is interesting to read this as I also had the same problem. My engine has a 920 Maney barrel. As is normal practice, Steve leaves his liners .003" to .004" proud. This means that even with a properly annealed copper gasket, there will be less contact where the gasket surrounds the pushrod tunnels & inlet valve area oil drain hole.
When I first built my engine I used Wellseal but a leak started & just got gradually worse. For attempt number two, I have used a German product from Motobins, the BMW spares people. It is Reinzosil ( Part No.95820) This should be applied in a fine bead to both sides of the gasket of your choice, only around the areas where oil will drain.
Hope this helps you.
Finally, where do the 81 dia. flame ring gaskets come from as I didn't know they were available.

Martyn.

I note your question 'is it worth persisting ? ' A lot is only psychological, I don't allow myself to reach that stage before I start extensively re-engineering . Your bike has not got a brain, you are in control. There is nothing on a commando which cannot be corrected satisfactorily. As far as the starter is concerned, I'd have a good long look at the aftermarket items and think about either modifying one to suit or using Japanese car parts.
Your bike looks really great !