And valve clearances can definitly lead to irratic idel. I had my bike schynched, double checked, triple checked, stipped the carbs, rebuild them, shynched them again and still she was dancing between 1500-2000 rpm. Did my valves (all were slightly in the tight side) and now she idels like a kitten purring.

(Can) Make a big difference!

Well it looks like i spoke too early, i went out to the garage ealier today to check the last few valves and get the rocker cover back on, and i actually have three valves that are too tight! So I've just spent the evening taking the camshafts out to get to the shims.

As soon as ive got some shims it'll all be going back together, but i took some photos for you mate so if you do end up doing it give us a shout if you need any guidance.

Cheers,
Matt

I did a compression test when I first got the bike - can't remember what the exact readings were but they were the same for each cylinder and within the green area on the gauge. If I remember correctly, the readings were slightly below the limits in the manual however I was testing the engine cold, and so put it down to this.

LP - I have about 18 months left, what jet sizes should I change to? I do have a straight-through can fitted by the way.

Cheers for all the input,
Wozza

it definately seems like the clearances need done.

and with 30k on the clocks i would do it anyway just for peace of mind.




william

all depends on what jets you already have fitted. if your in my boat and dont know whats already on the bike... its hard to know what to adjust them to. most people strip down and test/change as they go... or let a shop do it who have all the jets to select from.... same with shims in my book.

lol i had my valve clearances done for peace of mind in December... to be told they didnt need doing after all!(*).. 1st time i have ever had them looked at since i bought the bike... 6-7years ago of every day use!!! with 60K now on the clock..
(*) the shop kept on telling me that was the cause of my bike running rough... turned out to be carb rubbers brittle and cracked.

I know this sounds pedantic, you check your clearances because they NEED to be checked. Whether or not the shims need to be replaced is an entirely different matter, in your case LP you were lucky and everything was fine, but that didnt negate the NEED to check them......do you catch my drift? They DID need to be checked, they DIDNT need to be changed.
In any case as previously stated, if you're slightly mechanical get in there and do them, if nothing else it'll give you peace of mind and rule them out as a problem. Whilst your in there you can have a good old butchers and see if anything else in there could be the cause of your rattle.

Again thats just my tuppence worth.

aye.. but to check them you dont need to strip the rocker cover off etc.. a compression check will do.
the bike shop started off doing a compression check which showed normal and then stripped rocker cover off and again saw that they didnt need to be done.. in essence they should have listened to their own advice.. if the compression check shows ok.. valves are fine.

and to those who dont think compression checks are cods-wallop.. this comes from a bike workshop who deal with our age of bikes every day. they do know what they are on about.

LP we've had this discussion before and I'm afraid you're missing the point. The clearances DO need to be manually checked. A compression test will tell you if the clearances are too tight but NOT if the gap is too big, which incidentally would be the case when a tapping is present. As previously mentioned in this thread, if the gap is too tight for example from carbon build up, the valves wont seat properly giving a low compression reading so in this case the test will hilight it. If the clearance is too slack then the valves will sit perfectly and the compression reading will be normal, thus the compression test will tell you you have good compression, but the shims STILL need attention to take out the "slap".
Compression tests are a good diagnostic tool but it doesnt replace the mark one eyeball and a set of feeler gauges.

Nicely explained mate! Spot on you really cant beat manually checking, its worth doing even for peace of mind, to check them really isn't much work. I would imagine the reason the workshop rely on compression tests is becasue more often than not valves tighten up as opposed to being slack, due to valve stretch and valve seat wear. In my experience it is less common for the valves clearances to become slack, but as already said if there is a tapping then they obviously are, and its not unheard of.

It really is down to the individual engine, how its riden, if its warmed up, blah blah blah!

The point is that a compression test only tells you half the story.

true, but 1/2 a story you didnt have before...

i ride every day, warm bike up 1/2 a min to 1 min before i set off, longer in winter. it sees red line maybe once a month.. not a regular occurrence, change oil etc once a year around this time.