I had a few days off, so I've been doing some bits and pieces.
Now at 30,000 miles I thought I should check the valve clearances, since I'm positive this has never been done.

Adventure Spec Bashplate off (what an arse)
Panels off
Tank off
Drain the radiator + expansion tank
Radiator off
Turn engine to TDC and begin

All the valves seemed a little tight, so I adjusted them to correct tolerances:


I used a mid-point gauge so intake (rear) was set to 0.11mm, and exhaust (front) was 0.18mm

From start to finish, took about an hour and a half as I replaced O-rings too.
Have to put the bashplate back on, since it's part of the engine mounting and I don't want it shaking around (again, what an arse!)

Start the bike up and it sounds like a lawnmower. Rattle sounds coming from the top of the cylinder head and I knew something was amiss.


So here we go again, take it all to bits AGAIN. Bashplate off (arse), Drain the coolant, remove the rad, check clearances.

They are where I left them, except I noticed that perhaps each rocker wasn't exactly even on both sides. So i made sure they were even and I did them right up to the tightest tolerance. 0.09 and 0.16

Back together again (after this time cleaning all the crud out of the radiator fins)
Again, took me about an hour.


THIS TIME - still a bit rattly (I think coming from the exhaust valves) and took it for a spin and performance is down, feeling stifled a little.

So it seems I can't win! Too loose and it rattles. Too tight and it feels restricted and STILL rattles!

Looks like I'll be doing it again tomorrow.


Any tips?

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Bike: 2013 XT660Z, TKC70 tyres

Mods:
Barkbusters, Scottoiler, DIY Tail Mod, DNA Stage 3, Power Commander V & O2 Eliminator, Exan X-Black Stainless exhaust, Tool tube, Ohlins linear front fork springs, Nitron rear shock, JT front and Supersprox rear sprockets, D.I.D. VX 520 chain, Adventure Spec bashplate, DIY USB Outlet, DIY chain guide, Kev's Throttle mod

http://www.facebook.com/onemooseonemotorbike

Sorry to hear you're having problems with the valve clearances. It should be a straight forward job once all the components are removed.

Some things to consider....

Was the engine cold? it needs a good three hours to cool down as measurments should be taken cold and you will get a false reading otherwise.

Are you sure the piston is at top dead centre (tdc) and not 360 degrees out?
A good way to check this is to continue turning the engine and just after tdc the exhaust valves will start to open. If the inlet valves start to open first, you're 360 degrees out. To make sure you're turning in the correct direction put the bike on stand, in gear and turn the rear wheel in the direction of travel.

Finally double check the measurments you have for the gaps are correct.

hope this helps.....

9 degrees C here in sunny Buckinghamshire!

I'm pretty sure, both marks (one on timing wheel and one on cam sprocket) line up. There is an 'I' mark just after an 'H' mark that I'm going by.

Same measurements in the Service Manual, Owners Manual and Haynes manual


I have to give it another go, so I'll make sure 100% that it's on TDC but having done it twice, I'm fairly certain it's right.


Question - Do valves generally tighten or loosen with wear?
Should I do them at the tight end or the loose end of the tolerance or in between, like I originally did?


This is a bloody time-consuming job!

__________________
Bike: 2013 XT660Z, TKC70 tyres

Mods:
Barkbusters, Scottoiler, DIY Tail Mod, DNA Stage 3, Power Commander V & O2 Eliminator, Exan X-Black Stainless exhaust, Tool tube, Ohlins linear front fork springs, Nitron rear shock, JT front and Supersprox rear sprockets, D.I.D. VX 520 chain, Adventure Spec bashplate, DIY USB Outlet, DIY chain guide, Kev's Throttle mod

http://www.facebook.com/onemooseonemotorbike

Question - Do valves generally tighten or loosen with wear?
Should I do them at the tight end or the loose end of the tolerance or in between, like I originally did?

...the bikes I've owned and serviced I have found the gaps increase with screw and lock nut and tighten up with shims.
Probably best to set them in the middle of their tollerance like you have then once you've checked them a few times at each service you can second guess whether they'll tighten or loosen, THEN adjust to either end of the tollerance settings to give you more miles before they need checking again.

I can do mine without removing rad which will save you some time. steve.

Clearances for steel valves close over time/use regardless of whether they are screw and locknut or shim type due to valve seat wear or recession (and to a small degree the valve's face), making the valve sit deeper in the head. The seats will keep receding until the valve stem is in constant contact with the cam/rocker/tappet (no clearance) and the valve will not close properly with resulting lack of compression, power and possibly burnt valves.

High spec titanium valves can stretch a little over time and could possibly cause the clearances to widen, but this is often counteracted by the wear in the seat, so you don't often notice it happen. Titanium valve equipped bikes are almost always adjusted by shims and have much more regular valve clearance checks.

Ideally, for perfect engine performance, you want them as tight as you dare go without the minimal amount of clearance to allow for thermal expansion. However, in the real world, that would mean adjusting them every 1000 miles or so! The only reason we have 12000 mile valve adjustment intervals on the XT is because the clearances Yamaha decided on are on the sloppy side to accommodate valve seat recession. Theoretically the minimum they quote should be sufficient to last 12000 miles.

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Right, I couldn't wait til tomorrow so I've had it all apart again.

- Made sure the piston is at TDC
- Engine has been cold for 4 hours
- Clearances still in range (midway in tolerance)

So why does it sound like a lawnmower?

Going to do them up at the tight end and hope when I put it back together tomorrow that I don't have to do this again.
I think they were fine originally. Wish I'd never touched them!

__________________
Bike: 2013 XT660Z, TKC70 tyres

Mods:
Barkbusters, Scottoiler, DIY Tail Mod, DNA Stage 3, Power Commander V & O2 Eliminator, Exan X-Black Stainless exhaust, Tool tube, Ohlins linear front fork springs, Nitron rear shock, JT front and Supersprox rear sprockets, D.I.D. VX 520 chain, Adventure Spec bashplate, DIY USB Outlet, DIY chain guide, Kev's Throttle mod

http://www.facebook.com/onemooseonemotorbike

clutching at straws here but if you have had the bolts out of the exhaust guard one can vibrate on the pipe , I had to cut a bit off mine. That could cause the noise but of course not the poor engine performance .Steve.

I just undid the front bolt and swung it down far enough to uncover the "hatch".

I managed to adjust the valves on my Tenere with the rad and cooling system still in place.

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Simon

Brighton, UK

Noise tappet is a happy tappet.