Valve clearances

OK - so I finally got round to doing the pointy cam swap on my curvy earlier this week (and have been pleasantly surprised with the results).

Whilst I was in there I also measured the valve clearances. To sum it up all the exhaust valves are in spec but at the tight end of the limit apart from one on the front cylinder which is probably at around 0.19mm rather than spec which is 0.2 - 0.3mm. At the time I didn't have a suitable shim and use the bike for work so bolted everything back together.

Due to the wife and kids moaning I was considering taking the bike to a garage to get this sorted so rang one today to get a quote - I discussed it with the guy there who as very helpful but in short he recommended that as it was so close to spec he doesn't think its worth worrying about at the moment. He mentioned that if 0.2mm is spec then they wouldn't swap shims until clearance was 0.15mm or below - which surprised me a bit. He was adamant that at 0.19mm no damage will be done to the valve.

My question is whats everyone elses opinion - mine is that spec is spec and it should really be sorted. If I do leave this for another few thousand miles (I will be checking well before 15k more whatever) is it really going to matter. I'm confident it won't tighten quickly - initial wear was probably due to it being lean for a while after having the full system and filter fitted which has now been sorted.

Cheers, James

Slightly off topic but how much did they quote to do the job?

2 hours labour + cost of the shim (unless I supplied it) and coolant. I think it worked out around £80 all in. Bear in mind this was specifically to go into the front cylinder only, remove the exhaust cam, and change one of the shims.

[yorkie_chris]

I'd change it, you've done the cam swap so it will be nay bother, and will save you the worry. Presumably you looked at what shim size was in there?

[Mr_Chin]

£80 to change a shim! - yes please. Us guys in the South East are obviously getting bent over and seriously r@ped - I got quoted circa £270 by Suzuki, but another stealer quoted me nearer £400? For the sake of £80, I'd get it done just for the fun of it! I didn't need my done in the end, as a cager decided to write my bike off. Chin

You're .01mm below limit not even half a thou' in old money. Do you now how big this is? It's tiny, less than half a gnat's tadger, next time you take the top off and measure it, it will probably be in limit. Perhaps you should have just rubbed the shim on a bit of 1000 grit for a couple of seconds.

If it was me I'd leave it but as YC says it al depends on your piece of mind.
I take it you already have significant miles on the engine so I don't imagine you're valves are going to 'bed in' much more.

you do realise you can have errors too so it's not urgent to do. But there is piece of mind.

[jambo]

I do the valve clearances on the ZX6 every 12,000 miles, one day they'll be in tollerence, but at 50,000 miles it's not happened yet. For the effort of doing it I tend to find as I invariably have one out of whack, I change the ones close to the limit too.

Short answer: a 0.19mm clearance on an exhaust valve isn't going to cause you any significant problems provided you check the clearances again at a reasonable interval. If it were me, as the SV's so easy to do I'd have shimmed it out so it was nice and happy at the wide end of the clearance. But it's not going to blow up in your face.

Mr Chin: The OP has already checked the clearances and established only one needed changing, this probably altered the price significantly from "here's my bike can you do those clearance things" which will be a higher cost, especially if they're doing other service work along the way with that.

Jambo

[Mr_Chin]

Originally Posted by jambo

Mr Chin: The OP has already checked the clearances and established only one needed changing, this probably altered the price significantly from "here's my bike can you do those clearance things" which will be a higher cost, especially if they're doing other service work along the way with that.

Jambo

Granted, but No, I too checked the clearances, and found only one shim wasn't within tolerance - I told the dealers this, and I was still told:

"No problems, now bend over, son"

In the end, I was going to take my bike to a well-known Orger to change it for me, but the bike got written off in the meantime. As you stated, checking the clearances is easy, I can do it - changing a shim/putting correct shim in, isn't within my mechanical knowledge though. In any case, I can't see there being a significant amount more work to do in order to check and change a shim - It's just 'bonus day' for the dealers when a bike needs a big service.

Chin

[Spanner Man]

Good morning all.

Having seen plenty of engines where the tolerances are well under the minimum that have no apparent damage after re-shimming, I wouldn't be too concerned.
However, as said, you're aware of the problem so get it sorted. My preference is to shim to the upper end of the specified tolerance.

I usually charge between 2 & 3 hours for shimming both cylinders, depending on how many valves need shimming. So If, as said, you've informed the garage which shim needs changing £80 seems a trifle steep.


Cheers.