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Rob's WD16H and Big4 Forum

Dutch army, Johan Herman Fuhler, somewhere between 1945 and 1950

Rob's WD16H and Big4 Forum
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inlet valve "glued"

two weeks ago my 16h did not start. the inlet valve did not close. after having opened the cylinder head i realised that the valve stem was somehow glued. there was a resin-like material on the stem. after cleaning the valve stem the bike ran again for another 50 km. today, again the valve is permanently open. i onw the bike since august 13 and have ridden it for 800 miles. it runs very well all the time. any ideas? new valve springs needed?

Re: inlet valve "glued"

Martin, This is not 'normal' although my own valve guide problems have brought to light that neither Norton nor any of the later handbook writers ever quoted a stem to valve clearance so it maybe that yours is too tight.

Modern fuel lacks lubricity and I now use a Millers product containing manganese to combat this.

Has your fuel tank been sealed ? If so, then an ethanol fuel could be softening the sealant and allowing it to be deposited around the inlet. I've heard of this problem with a number of OHV engines.

Re: inlet valve "glued"

thanks for your reply.
the fuel tank is sealed by a professional as there were two leaks to be welded. i trust the guy's sealant as he offers welding and sealing for decades.
i dont think that the clearance is too tight as there were no probs for about 800 miles before including a 300 km trip through germany in august last year with temperatures of more than 30 degree celsius.

maybe the valve springs are too weak?

Re: inlet valve "glued"

It's possible the valve springs require renewing but before changing them try greasing the grease nipples on the guides if you haven't already tried that.

Re: inlet valve "glued"

I had the same some time ago, with a big 6 cylinder engine, there was very old petrol in it, ran OK on it, but the next day all valves were stuck! also a white glue like substance, very strange, after renewing the petrol, no more problems.

Hope this helps,

Lex

Re: inlet valve "glued"

the strange thing is, that the engine ran very well without any probs for about 800 miles. this bike does not suffer from any old petrol or whatever.
as far as i understand, my problem seems to be quite "unnormal".

could you please let me know which kind of grease you use for the valve stems?

Re: inlet valve "glued"

Check the carb to see if you have anything in the bowl. This will prove or not whether it's coming from the tank. Have you used any type of grease on the valve stems? If you have, maybe that grease isn't heat resistant and is burning onto the valve stems and gluing them up?

Re: inlet valve "glued"

martin
the strange thing is, that the engine ran very well without any probs for about 800 miles. this bike does not suffer from any old petrol or whatever.
as far as i understand, my problem seems to be quite "unnormal".

could you please let me know which kind of grease you use for the valve stems?


Hi Martin, I just use ordinary multipurpose grease, same as for the other greasing points, have never had any probs. The Workshop Manual calls it C600 grease same as used for fork spindles, head races etc. A different type Gr No 2 ,which I suspect has a higher melting point, is used for brake cam spindles and wheel bearings.



Re: inlet valve "glued"

thanks for the info about the grease, keith.
today i unscrewed the grease nipples and found some black resin-like old grease. it was rather hard than liquid. i have cleaned the area and will apply some new normal grease. hopefully, this will cure the problem.

cheers from frankonia, martin

Re: inlet valve "glued"

it seems as if my work was successful. the bike started well and ran very well for about 15 km.
thanks for your input!

Re: inlet valve "glued"

Hi Martin,
my first choice for the valve greasing is Castrol LMX which has a high temperature stabilization. The first thing I did was to replace the majority of the grease nipples by new ones.
I would even rather go for pumping oil in the valve grease points than grease, I have not yet got why grease is used at the valves.
To be on the safe side wrt corrosion in tank and carburettor I add synthetic 2 stroke oil to the petrol 1:200. I also do this with my Triumph car.

Heiko

Re: inlet valve "glued"

Heiko
Hi Martin,
my first choice for the valve greasing is Castrol LMX which has a high temperature stabilization. The first thing I did was to replace the majority of the grease nipples by new ones.
I would even rather go for pumping oil in the valve grease points than grease, I have not yet got why grease is used at the valves.

Heiko


Heiko
You can of course use whatever you like, the bike is yours, but personally I prefer to use the manufacturers recommendations as per my post 8 of this thread. I have done this since 1976 without any problems.
Keith H

Re: inlet valve "glued"

I think one of the problems here Keith is that Grease has changed in terms of the solids included with probably little account taken of engines with open valves and fuel has also changed enormously.

I suspect that valves and guides with some mileage on and a reasonable clearance may not show problems but I've had no end of valve and guide trouble.

I'm now using engine oil at roughly 50 mile intervals on the assumption that clean engine oil can't do any harm and a grease of unknown composition perhaps could.

I suspect that grease was specified originally as it was the best way to extend the lubrication intervals and that a build up of grease around the guide would give some residual lubrication even if it wasn't done regularly. Manufacturers are always under pressure to make their service intervals user-friendly but that doesn't mean that they can't be improved upon.

Re: inlet valve "glued"

Keith,
your longterm experience is the best advice, I would stick to this no question.
We are talking about the same grease, the No.2 spec is most probably the NLGI specification, the LMX is the No.2 grease from Castrol whereas standard grease is normally not.
The datasheet says:
Castrol LMX
Base Lithium Complex
NLGI Classification 2
Worked Penetration, 60 Strokes 265
Drop Point, °C 260
Operating Temperature, Min. °C -30 Max. °C 150

Thanks,
Heiko

Re: inlet valve "glued"

We used to use a moly disulphide grease on open valve gear (on a 1920's car). Norton SV valve guides are probably an ideal application I should have thought. Messy stuff...

Re: inlet valve "glued"

Gents,

I have used both molybdenum grease and airgun grease. But not for long.

Having the idea that its all gone through the exhaust before you have left your home street I just stopped greasing alltogether.

Have not had any problem for over 10.000 km.

OK, I may not have the best of compression but I also seldom push the bike to its limits.

This is not a call to stop greasing, only to show that what you do, it is not necessarily going to be wrong, and these MC's can take a hell of abuse and still run happily.

Cheers,

Rob