www.zxrworld.co.uk

Ok this is great.

I ran the bike for about 40 miles last week and and noticed a knocking sound coming from the top end.
First I though it was the valves tapping the pistons (stupid I know) as the head has been skimmed to it's limit.
I was then told it could be valve clearances. So I endeavoured to check them last night.

They are all pretty tight so i'm going to need some more shims but the interesting thing is, exhaust valve #2 for cylinder 4 HAS NO SHIM!!!!!
I could get the entire feeler gauge in the gap.
The rocker arm has made a slight imperfection around the shim seat.

Would the imperfection prevent the shim from sitting properly? Am i going to need to replace the tope part of the valve?

Thanks in advance

I reckon the real questions here are........................where is that shim ? what caused it to be ejected from it's proper location ? Are the valve collets still CORRECTLY in place?

And it is perfectly reasonable for valve and piston to touch if an engine is incorrectly built AND it is possible that a valve and piston meeting could pop the shim out of place. Especially on a head "skimned to it's limit" (One wonders what that actually is)

If this was my race bike I'd not be racing it until I know for sure exactly what went on and that it was fixed and the missing shim recovered

I gave the head to a chap I know to be skimmed (valves in) presuming he knew what he was doing. The head was skimmed with the valves in (stupid i know) which resulted in a couple of them being clipped. I didn't check the shims when I put the head back (again, very stupid) because everything was in tact - I trusted the guy as well (he's an old/experienced fella). I'm hoping that it fell out during the skimming process - I'm pretty sure I wouldn't have done the 40-50 miles on it if it had managed to get inside the engine.

I'm sure the engine has been put back together correctly I spent a while on it and ensured the cam timing was right.
Although, I started checking the clearances last night and they all seem quite tight.

e.g. Cylinder #2 inlet's gap is 0.08 - tolerance is .12 - .17 I believe. The ones I have checked are around 0.4/2 too small.

Could this have caused it?

I'm sorry to appear negative...........but if the shim fell out during the skimming process then you can hardly claim to have put it back together correctly putting it back together correctly would have involved checking that everything was there and in the correct place. mind you getting it skimmed correctly would have involved removing all the shims.............

That shim could be in your engine for a thousand miles and you'd never know untill you landed on your backside in a field wondering what happened

given that you said it was skimmed to the limit (whatever that is) I would have said that putting it back together correctly would involve checking the valve/ piston clearance..................as this will have changed no matter how carefulyl you lined up the camshafts and valve timing.

Having the valve clearances on the tight side means the valve opens earlier and is open for longer which also might bring it into conflict with the piston more so since you skimmed the head "to it's limit"....................


if it was mine I'd rub it out and start again

Ouch.

To be fair this was my first 4 cylinder 'Rebuild' and I had help from a few friends. The chap who skimmed the head told me it was ready to just bolt back on - So naturally i took his advice.

Rub it out?

Could it have made it to the crank case if it is in there somewhere?

Cargo is suggesting you bin the engine or at least the top end if you find the missing shim.

If your lucky it has popped out and laying about in the top end - poke about the puddles of oil , next is the oil ways - these are big enough for the shim to go down but it will stop when it gets to the crankcases so cut a steel cothanger straighten it out and using a strong magnet on it poke down each one and see if you pull it out from there.

If it's fallen down the chain tunnel sounds like you got lucky it didn't get jammed in the lower cog and caused all sorts of nightmares for you, so take off your pulsar cover (in front of clutch) and have a look around there. Still no sign off it then its sump off time and poke about it after that it's a full engine strip to clarify if it was ever there to start with - you do not want it suddenly dislodging and seizing your engine at silly speeds !!

If your worried about valve to piston contact you need plastigauge and check what clearance you got left if any - I think Mick uses modelling clay which will certainly show you have something left !

If you remove head and the valves have made contact you should see evidence on the piston crowns , if it hasn't been heavy you might off not bent valve stems.


It looks like I will be doing another engine shipment soon so I am going to service at least two of the motors I have here for direct bolt n play use - no removing covers , no adjusting shims or taking measurements. Fill with oil , fit your fav' spark plugs and go.

One will be an L engine with SP cams and other an H engine with same grind static cams from a ZX-4, if time permits a 3rd either my H2 motor currently in the bike, another L engine I havent inspected yet or a J2 SP motor. All with have had full top end overhauls done including valve stem oil seals and I will have detail photos of each service carried out and parts used. Engines are too low mileage for camchain worries but tensioners will all be L9 and if any blades have deteriated with time replaced.

I will offer up on board for pick up from London initially otherwise they will go on EBay.

Good luck on your shim hunt , oh - loose clearances are prefferable to tight ones unless your building a race engine as it will produce more BHP with tighter settings.

MM!

Thanks for the advice guys.

I'll have a poke round and let you know what happens.

Thanks again

When I say rub it out and start again..............I mean rebuild it from scratch and find that shim.

As for the damage where the shim goes so long as a replacement shim fits properly and the valve is straight I see no reason not to leave it.............oh and check the rocker for damage

Just noticed this

viewtopic.php?f=117&t=12451


seems your shim was missing back in April

Jeez, if I'd been running about on a bike with this problem for a month I'd be turning a ghastly shade of white right now

I haven't been using the bike. I only used it once just to test it out.

It would seem as though the shim has been missing since I had the head skimmed - according to the guy that skimmed it.
The wanker didn't even tell me until now.

Gonna measure the clearances and get her back on the road.

About 4 posts back he was a trusted old fella..........................


Checking for shims was NOT the job of the guy doing the skimming............in fact the shims should have been removed from the head before he was given it to do the skimming job.........................I think I know who the self abuser really is


Best thread in a long time

Yeah thanks for that.
Nothing better than trying to get along and learn something when you have someone on a high horse trying to make you feel like an idiot.

Like I said this was my first rebuild and I was told to just give the head as it was and he would sort out the rest.
I also thought that I could get help from this forum (I have so thanks everyone) but the last thing I wanted was to be patronised.

:wanker

Azazel , as we all know some time typed words don't reflect what we are actually trying to potray

I hold my hand up to that offence - if someones goin to piss ya off it's likely going to be , by no mailce but just typing my mind rather than structuring sentances

From what I see you were the first to throw boulders ie. adverting your blame to someone else or " a bad tradesman blames his tools "

On the rebuild you were responsible for the final completion - a missing shim shows you never done that and passing blame doesn't get away from that.

Taking it on the chin and admitting you arsed up we would all luagh & cry for you - I will place my hand on heart and say " we have all been there " should some one chime in saying they haven't you have my full permission to pull out the "making love to Pam" emotion

You will find all the info you ever need on this site to maintain , tune and service your bike to peek performance - it's not a black art but you do need to have some ability at "spannering"

You will however get hammered on any forum wether your in the right or wrong - that's sods law

I certainly don't think you as out on the side lines but part of the forum and so you should be , haven't read anything that's made me think otherwise but you do need to reflect what you have said and what you want to say next otherwise you will (we all will) get ripped to parts as others have the luxury to analyse in an armchair while we type at our wits end.

The good news is - you have established the fault was there all along - you will learn from that , don't pull the Red mist down and blur this memory. When you work on your bike you do the work and you have to trust your work 100% , let no one tell you otherwise ie. " thats good to go mate " is NOT to be trusted.

Me mate Ally had his 750turbo serviced at a Kawasaki dealer and was told " Thats good to go " and the thing seized and shat it's pants his first thrashing - their attidude " nothin to do with us " , that's what your trusted fella has just done - if the head gasket had blown then he is too blame , a missing shim has nothing to do with skimming a head.

What i will say not as strongly as Cargo is " You should have removed all shims before having the head skimmed " , you weren't to know this but now you do.

So, now you know the problem - average out what size of shims are in the other valves ( only for that side ie. in or out) and put a shim of that value in , measure gap and work out if it's within tolerance and if not what way you need to go to get it in tolerance.

MM!

Had our friends use of the self abuser word been 'imed at another forum member I would have removed it.
As ever MM explains the truth in much more gentlee way than I ever could for me a spade is a spade.
We have a main dealer here that sold a new bike and waved the new owner off on his way on a bike with no oil in it ! He didn't get far.
They also once sold a bike and forgot to tighten the front wheel spindle the owner got a little further but crashed.