Does anyone here pay their garage to check & if necessary re-shim their valve clearances these days?
I’m excluding owners of newish bikes from this, as if under warranty and dealer servicing, I’ll take it as a given that you’ll be getting the required work done. I’m also excluding owners of the upper end stuff like Ducatis, litre sportsbikes etc, who I would largely assume give their bike all the love and attention it deserves.
No, I’m talking Bandits, SVs, Diversions, Fazers, CBF500/600s, ER6s, Versys’ etc. Your decent run-of-the-mill all-rounders.
Reason I ask is that a friend had his Kawa KLX650 serviced last week and asked the mechanic if he thought the valve clearances should be checked and adjusted if required. The reply was “Why? Is it not running right? Difficult to start?” My friend had no issues with the running of the bike, so the mechanic said to just leave it then, and save yourself the money.
I got stung a while back for £150 for some minor ‘re-shimming’, and I don’t believe the clearance were ever even checked. So what about you guys with the mid-range run-of-the-mill bikes… Does anyone pay a garage to do their clearances, and if so, do you think they actually get done???
The Bonne’ has not seen a garage/dealer since it’s first free (you pay for the oil & filter) 500 mile service
The Triumph service recommendation is every 12,000 miles to check/adjust valve clearances which I have always done myself. At all previous service intervals I have found all clearances to be right on the service limit except one of the No.2 cylinder exhaust valves, which appears to have been 0.05 mm over the service limit from the factory. Now on the third service interval I’ve found the No.2 cylinder inlet clearances outside the service limit too, mainly due to wear on the inlet camshaft lobes, none of the other clearances have altered over three service intervals and the engine has always run fine. Just waiting on delivery of three shims as I type.
So is it worthwhile to check the valve clearances? Definitely, especially as it also offers the opportunity to inspect the camshaft and the camshaft running gear ~ chain, tensioner, sprockets, oil feeds etc. It’s good to know all is well under the cam cover when you hit that red line and if that’s not good enough reason for you Google ‘valve bounce’
Mechanic I know said that a lot of bikes - particularly Japanese like Honda tend to stay in clearance after their initial check - but It’s still worth checking them yourself at the required service intervals for piece of mind if nothing else.
The job of checking can be fiddly and time consuming but isn’t that difficult if you have a Haynes manual.
If you find that you are out of clearance - then the job of replacing the shims does require a bit of skill and experience, so in that case if you have established for yourself that the bike needs re-shimming you can then take the bike to a pro to complete the job.
Check it yourself and chances are the bike will be in clearance and you will have saved yourself a few bob + plus you will know everything is cushti under the valve cover.
Old bandits are a piece of piss to adjust as all you need is a spanner - no shims to replace.
That’s true - although there is a school of thought ( from what I have read on the forum ) of “if it ain’t broke” etc.)
What seems to be the biggest bogeyman among Ducatistas is “belt fear” - ie if you don’t change them religiously 7500k or 2 years then they will snap with £expensive consequences.
Then others say 3 years is ok …
A guy tried to sell me a 999s that needed a belt service and I mentioned shims - he said “If it ain’t broke…” … Now a shim service on those is a big job, tank off, seat off. part of subframe off - loads of other things, battery , airbox, etc etc to come off before you can get to the complicated heads and shims… I didn’t buy the thing - too scared! :crazy:
Probably not, it’s just that the rest of em don’t brag about it
Here’s a nice article on adjusting valves which has a section
“Doing the maths” which says that a new shim should be selected
to get the clearance to the upper end of the tolerance to allow
for future wear.
i.e. a worn valves clearance gets too tight so it does not fully
close then it will leak and a compression test will detect it.
lol it’s not that I’m proud of being incompetent, I just don’t feel very confident tinkering with a machine that has the potential to kill me…
I would love to learn more about the mechanics of it all, I did send the guys at Oval an email about their basic maintenance course but haven’t heard anything back, I will give them a call when I have a chance.
It just seems like every biker I speak to knows everything about the nuts and bolts on their bike, I don’t even understand what you guys are talking about! :crazy:
A compression test will only indicate whether or not the valve seats, seals, springs and guides (as well as the head gasket, piston rings and cylinder bores) are in a serviceable condition. The valves could be seating perfectly well with the valve clearances way outside of manufacturers tolerances. Also a compression test is done on the starter motor at low revs. Although I do it by driving the alternator rotor bolt with a 10 mm hex key on an electric drill The higher an engine revs the more critical valve clearances become, I wouldn’t want to be hitting the red line too often with things they way they were on the Bonne’.
Of interest, I did a compression test on the Bonne’ before stripping the camshafts out and the readings I got were fine ~ 9 bar initially and rising rapidly to near enough 14 bar by the fourth or fifth stroke, on a 10.2:1 compression ratio that’s pretty much as good as it gets. Even with excellent compression readings three valve clearances were 0.05 mm outside manufacturers tolerances.
I must disagree with the maths, the correct way is to aim for the midway point, for example …
If manufactures tolerance is 0.25 to 0.30 mm and the clearance is outside of that say 0.35 then the point to aim for is 0.275. The reason for this is that shims are only available in increments, depending on manufacturer, of 0.25mm or 0.05 mm. Clearances that are too tight are as bad if not worse than clearances are too loose.
All the service manuals give the formulae a=(b-c)+d where ‘a’ is the new shim thickness, ‘b’ is the measured valve clearance, ‘c’ is the mid point of the manufacturers tolerance and ‘d’ is the measured thickness of the existing shim. Note the actual figure this formulae returns for the replacement shim needs to be adjusted according to the manufacturers shim increments.