Hi All, finally started up my 1962 A65 Star yesterday after a full engine re-build. It started readily and soon chimed in to a lovely even beat and tickover (helped no doubt courtesy of a new Amal Premier and the wonderful Tri-Spark ignition kit-both seem good kit to me and no I`ve no connection to either firm!!)
BUT----- the deafening clatter from the valve gear emanating from the cylinder head..... Crikey..... Now I know British classic bikes are a bit clattery at the best of times but this seems excessive. Are all A65`s this noisy??
Bike has EVERYTHING done: re-ground and balanced crank, billet rods, mains roller conversion, SRM pump,re-bore (GPM pistons), new (Hepolite) cam/bushes, re-ground followers, full head job (SRM) with new guides/valves, re-cut seats.
It`s had the works really, and carefully/cleanly re- assembled to boot. Barrels/head never been skimmed and standard copper head gasket fitted, so all should be as per the book, but I wonder whether the valves are maybe just contacting the pistons?
It turns over smoothly by hand with the plugs out with no resistance other than the compression of the valve springs. It does however make a repeated CL- CLAT CLAT every turn as the valve springs reverse the cam backlash to and fro as the lobes ride over max lift- an unavoidable feature of a parallel twin engine I suppose but it seems excessively loud to me....
Any ideas before I start to investigate?? It really does seem to be running very well, but just so damn noisy on the valve gear :(
As the saying goes. They all do that sir.
Any chance of a video clip so we can hear the engine running?
Hi,
One thing that can add to this noise is the idler gear to which the points cam is attached. If there is excessive end float this can in effect rattle a bit. Earlier engines had idler bushes with a thrust face whilst later ones did not. If the bearings faces are quite worn then the idler gear has more chance of rattling in and out. On the earlier gears new bushes should reduce this but on the later ones it may be necessary to use shims to get the end float down. I try to get about 10 thou or if you use PTFE or teflon shims a zero clearance can be aimed for as the shims will morph to bush and gear giving any clearance needed.
One other thing to consider is that some inner timing case gaskets are quite thick and as a result the end float is increased so making the case for a shim of some sort stronger.
There is also the inevitable wear on the gear teeth which can only be fully overcome by getting new gears. It is also possible to increase the amount of oil that gets to the gears by slight modification of the oil holes designed to take oil splash from the cases to the bushes this increase will in turn get more oil to the gears with a reduction in noise.
Dave.
Having had a look this morning I have concluded that:
A) With any valve on full lift, I can(with judicious use of a long screwdriver on the rocker) open that valve further, thus confirming that no spring coil binding is occuring.
B) That the pistons are not getting anywhere near the valves (I was concerned they may have been touching for some reason)
So, all seems well.... I`m inclined to agree with Dave that backlash in the geartrain is contributing as the idler shaft is worn and they are not available (early type) and the clat clat I mentioned does come from the idler/points area when engine turned over on the kickstart.
Perhaps its just a case of they are all that noisy- I`ll have to listen next time I see one at a bike meet!
I will try to post a film of it running but it will be a couple of days yet as the oil pressure switch I have fitted leaks and has been sent back for replacement >:(
I went along to hear a forum member's A65 a week or so back because he thought the primary drive in particular was noisy. I think he posted a video which sounded ok. When I heard the actual bike, it also sounded perfectly normal and, if anything, sounded slightly quieter than many others I've heard. However, it's always reassuring to be told the bike is not making any unusual sounds!
That was me , heres the link , to me the noise is quite noticable but am reassured by spaceman that its nothing to critical .
https://youtube.com/shorts/PUHP-Fx-dlk?feature=share
Hi,
Maybe worth experimenting with the timing a little, it has made a difference to mine. Also the fuel? Shell V-Power unleaded seems to help rather than the E10.
Best wishes...
:) :) :) :)
I just watched the vid and listened to the engine. Sounds like a much quietier version of my A50.
Mike 8) 8) 8) 8)