If valve clearances are not set right, what are the symptoms? I believe a rattling sound? Is that true, and if so would it be constant, and are the symptoms the same for inlet and exhaust? I ask because I have an intermittent rattle. I don't think it's coming from the engine, but I can't locate it so am beginning to wonder. Thanks in advance. Phil
The cam lobes are fitted with quietening ramps designed to reduce the rattle from the valve operating mechanism provided the clearances are properly set. If the clearances are too large, you will get a rattle from the rocker box - from both ends if the inlet and exhaust clearances are out. The rattle won't be intermittent but could reduce significantly when the engine warms up. That said, the rattle from excessive valve clearances is not normally that bad as to be a big source of worry under normal circumstances? Easiest way of ruling out the rocker box as the source of the rattle is to check the clearances!
Thanks AWJDT. My rattle is intermittent so I guess not connected. Last time I tried to set valve clearances I had two problems: 1. difficult to get feeler gauge in, due to shortage of space; and 2. Couldn't get the locknut undone. A bike mechanic told me as long as I could feel a bit of clearance it would be okay. Phil
Hi Phil. I ended up taking the feeler gauge holder apart and taking out the specific ones needed and bent the tips. Still easier with the tank off though.
I put some wd40 on the treads and left it overnight. also found a longer armed spanner.
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
Good morning,
Are your adjusters the square top type? If you do not have a specific tool that fits properly then a brake adjuster tool should fit. This is type with a square hole at each end. One end should fit.
Use a long ring spanner and the 'brake' spanner at the same time to get a bit of extra torque for undoing and obviously turn them both together in an anti-clockwise direction.
When adjusting, the brake spanner can be used to easily hold the adjuster still whilst tightening the lock nut.
As has been mentioned they are easily overtightened so use a short spanner when doing this to reduce the leverage. If you do not have a short spanner then put some tape on the spanner the width of your fingers and only use this shorter part to tighten.
There are some spanners, especially ring spanners, that are far too long so that small fasteners can be over tightened or indeed sheared off without much effort.
Dave.
Turn them both together, you say? From memory, shouldn't I be holding the square one steady whilst I undo the hex one?
Normally that should work but yours seems to have been over tightened so try putting them on together and turn both at the same time. The brake spanner on its own will not do it and may round off the square on the adjuster.
If the square on the adjuster is already rounded then there is no alternative to the ring spanner and plenty of grunt.
Dave.
Quote from: Phil C on 05 Jul, 2020, 21:42
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
The lock nuts always tend to be hard to undo, possibly because the hammering action against the valve stems deforms the adjuster thread slightly. I find the trick is always to use a well fitting spanner and then deliver a very firm tap with a soft hammer (or for me, the side of my hand) to break the lock. This is the equivalent of using an impact wrench!
Sorry, a firm tap against the end of the spanner!
No hurry to do this, but I thought I'd just have a quick look, to see what size the square drive is so that I could buy an adjuster tool. Two things struck me: 1. Not much of the square adjuster to get a purchase on, is there? and 2. the square drive looks to be about 5.5mm across. Maybe 7/32"? I was expecting a more standard size, such as 1/4", for which I'd be able to get an adjuster tool. Anybody know the size, and if tools are available? Thanks as always. Phil.
If the nuts are very tight I just use a good fitting socket and bar. Never had one break. Important also not to lock them up too tight as said before the locknuts seem to get tighter with time!
I tried a brake adjuster spanner but none of mine fitted the square adjusters. I have a set of BA spanner's and find that one of them is close enough to hold the adjuster while locking the nut with a thin ring spanner. I also butchered some feeler gauges to make individual bent ones for each tappet.
I believe Rupert Ratio suggests smaller clearances than the WSM - I haven't got a copy so can not confirm but someone here probably will.
My tappets on my B40 and A50 are still noisy to some degree after adjusting.
I also normally use a BA spanner to hold the adjuster. AdrianS is right about RR who sets the clearances by ear rather than using feeler gauges which is probably not recommended for the inexperienced. I use the ear technique as a quick check that the clearances are basically ok but always use feeler gauges to set the clearances precisely.
Thanks very much. Meanwhile, my rattle, which we established would not be tappet-connected because it was intermittent, appears possibly to have disappeared. I've just been out for a quick ride - just a couple of miles - and didn't hear it. The reason I popped out was to see if the rattle had gone, as it occurred to me it might have been the fork tongue/ brake plate play, which I recently shimmed. Maybe that was it. Fingers crossed. Phil
Top tip. Don't check the valve clearance with the 'valve lifter engaged!! Been scratching my head wondering where the gap had gone on the exhaust side....despite not having adjusted that side !! Must have done a few miles manually turning the engine over!......then going away, having a cuppa tea. Then repeating !
Decompressor is a much better name really. It doesn't lift unless seen from Australia.
How did you come to have it engaged? Is it not actuated by a lever like a half-size clutch lever?
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.
Quote from: Phil C on 05 Jul, 2020, 21:42
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
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.
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.
Yes, that is the best way as it records total motion and not just the distances between the flat faces.
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.
A much easier task if you fit the adjusters that take an allen key
[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.
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.
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.
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.