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?
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.
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?
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.
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,
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?
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?
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
it seems as if my work was successful. the bike started well and ran very well for about 15 km.
thanks for your input!
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.
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.
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:
Base Lithium Complex
NLGI Classification 2
Worked Penetration, 60 Strokes 265
Drop Point, °C 260
Operating Temperature, Min. °C -30 Max. °C 150
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...
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.