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[Bullet Whisperer]

Bear in mind any valve 'clearance' on the Bullets will INCREASE as the engine warms up, which is why they can be set at 'Nil' clearance when cold, so your 0.002" clearance will become larger as the engine warms up.

[Alan R]

Hi Guys-----Just to clarify a point I made earlier}--- I'm not suggesting that you actually have Valve Seat Recession, just that the symptoms are the same, that's all....

[Tomshayes]

Hi Paul

That's what I was wondering.. So If the gap increases as it gets hotter the valves won't have any problem shutting..

I was concerned that the opposite might be happening....

I set the tappets at a "Loose" "0" both pushrods spinning freely when cold.

Should I gap them to 0.002"

Tom

[papasmurf]

I would be interested to know how it is possible to set an accurate gap on a ball and cup adjuster.

[Bullet Whisperer]

Not too interesting really, Papasmurf, but it has to be done between the end of the rocker and the valve stem, so the rocker covers and fuel tank would have to come off for access. In reality, it is not really necessary, just back an adjuster off by a spanner flat or two from zero clearance, to grab a couple of thou if you want them. Regards, Paul.

[Tomshayes]

I'm going to retorque the head so the rockerboxes will be off anyway!

Tom

[Alan R]

Hi Guys-----If I might just expand on Paul's answer a bit-------I'm not trying to be patronising here but the non-engineering guys might find this bit of info useful}-----The principle is quite easy and relies on you knowing ( or estimating ) what the thread is on your adjuster .........Just for example let's say the thread is 40 tpi ( Threads or turns per inch..) .......Basic maths says that one turn is therefore 1/40th inch or 0.025" or twenty five thou..........Now assuming that the adjusting rod is turned from -- or attached to a piece of hexagon ( 6 sides ) then by moving just one flat of that hexagon ( ie 1/6th ) we will have moved 1/6 of 0.025" which is}----- 0.004" or four thou !!................It's also how your Imperial Micrometer works.....A 40 tpi thread divided by 25 gives 0.001" divisions..

You can use the same idea with an engine that has a starter ring gear on the flywheel...........Count the number of teeth on the ring gear then divide it by 360 ( degrees )..... This gives you Degrees per tooth and from that knowledge you can set up ignition or injection timing, valve timing, etc....

[Tomshayes]

Well I've gapped tappets to 0.002"... Started it up and it still cuts out after a minute or so running... Checked the fuel flow.. No problem there... Carb bowl and needle jet etc is clean... Don't think it's a fuel problem.. The bike doesn't get hot... Still touchable warm... New plug.. And there is a spark after it cuts out... No indie noises etc.. Engine was hunting a bit but I've not had a chance to tweak the carb yet.. It cuts out before I get a chance... I did notice that the oil had all disappeared.. I've fitted new hi capacity pumps.. No oil on dipstick.. I poured a fair slug of oil into throat of crankcases.. And filled oil tank... Oil appears to be reaching rockers etc...

I would expect the oil level to drop a bit but it seems a bit excessive..

[Alan R]

At first reading of those symptoms it seems like your idling jet is too small........What colour is that spark ??.... and do you hear a nice, well defined "crack" ??

[Alan R]

How soon after stopping can you re-start it ??---------Can you test-run it without the rocker covers on to see if a valve is being held partially open ??