Valve clearances - symptoms

[Phil C]

How did you come to have it engaged? Is it not actuated by a lever like a half-size clutch lever?

[hoogerbooger]

I engaged it to make it easy to find TDC by turning the back wheel........then had a cuppa tea and forgot. (Clever eh!)

What I have learnt though is it seems easier to find TDC by eyeballing the piston directly down the spark plug hole  rocking the wheel, than using a gauge.

[Phil C]

Hi Hoogerbooger, Yes, I did that with the feeler gauge, but I never did get the locknut undone - I gave it some WD40 but was giving it so much force I was getting scared of causing damage. I knew that try again.  Phil

Hoogerbooger, Looking through some old posts just now I came across this discussion and was shocked to see at the end of the attached post I appear to have written " I knew that try again". That sounds very rude, and I assure you was absolutely not what I meant to write. I can't remember what I did mean to write, but it wasn't that! Maybe predictive text was doing its worst. Anyway, sorry.  Phil

[Blackthou]

In addition to all the above the exhaust clearance was fair enough to set but in case overlooked, it should be noted that to set the inlet clearance the exhaust valve should not be open but just at the point the clearnace in the exhaust valve pushrod is taken up.

[Colin SS90]

I use a dial indicator onto the top of the adjusters to set valve clearances, must easier than feeler gauges, but it does take a bit of time to set up.

[Blackthou]

Yes, that is the best way as it records total motion and not just the distances between the flat faces.

[Colin SS90]

Rupert Ratio suggests adjusting the clearances until you can just feel slight movement of the rocker whilst the pushrod still rotates freely by hand. I tried this and then measured using the dial indicator method which recorded 0.002"/0.003" of clearance. I thought this was too tight and the 0.008"/0.010" recommended clearances too loose, so I set mine to 0.006" for inlet and exhaust which I thought would be a happy medium, this resulted in fairly quiet tappets. This setting is just my personal preference and I plan to check the clearances quite regularly as when the valves bed into the seats the clearance will reduce.

[Dean Southall]

A much easier task if you fit the adjusters that take an allen key

[hoogerbooger]

[Can I thank hoogerbooger  (err, that username sounds a bit familiar?) for his top tip about not having the the valve lifter engaged......as a search on the forum has just solved where my exhaust valve  clearance had gone.......derrr!!.........demonstrating that I have a memory span of less than 3 years !!]

So my B40 exhaust valve clearance is a bit over the 0.01" ( 0.25mm). I can get a 0.3mm feeler in...... but not quite sliding through. ( gaps seems to narrow upwards towards the rocker side)

Was thinking of adjusting it down to get close to the 0.25mm.........but the lock nut on the exhaust tappet is a bit mashed and none of my ring spanners/sockets fit. If I could take it right out I can file the mashed corners back..... but my small adjustable has some play in the mechanism making me think it'll ping off....when I tap it ....and I'll gash the rocker opening.

Any tips ? 

I can't file it in situ without getting filings in the rocker box.  All I can think is leave it for now and address this if/when the rocker cover comes off.......... & put up with some extra rattle for a while....possibly a long while.

[Spaceman]

If the problem is that you can't undo the lock nut because the spanner/wrench won't fit, I would just get out my long nosed mole grips to undo. Alternatively, if you want to be brutal, just use a centre punch and hammer to deliver a tangential blow to the nut. Once off, I would definitely replace by a new nut which are cheap enough - 5/16" BSC.

[cdsdorset]

Get a decent quality single hex socket to fit the nut properly. If the nut is slightly rounded get one of the sockets that drive on the side face of the nut.

[Pete C]

I'm not sure about your adjusters but most brit bikes seem to have used cycle thread at 26TPI so 1 complete turn is around 40 thou. You can work out the angle you need to turn the adjuster through from the closed position to get the required gap.