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Shimmed Valve clearance check/adjustment?

Discussion in 'Maintenance and Servicing' started by dobbo, Mar 5, 2013.

  1. Hi,

    I am about to takle a valve clearance inspection (and maybe adjustment) on my Yamaha XJR13, four cyl EFI. Shimmed type valves.

    I am a 'backyard mechanic' and a novice at that. I have done top-ends on 2 strokes, and regularly do all the servicing on my single cyclinder bike including valve clearance checks/adjustments, with the nut adjusting type valves.

    I asked a local bike mechanic about this job, and he said it was time consuming and could end up a pain in the A, as you may need an assortment of shims and a Specific valve tool, when asked if a backyard mech would take on this job, he said NO!

    My local Yamaha mech is around 2 hours away.

    I may not have to adjust anything, but this is part of the service schedule and I don't mind tinkering.

    Am I mad for taking this on????:nailbiting:
  2. Do you know what size shims you bike takes? the 9.5mm Yamaha ones are very hard to find...

    I would check the clearances & go from there.

    If they are out, you need to remove the shims, measure them, then work out which ones you need. It's not hard, just time consuming. You shouldn't need any special tools, unless they're specific to your bike.

    Some bikes shops will charge you $15 per shim, WITH a trade in of your old shims.

    Once you've worked out the shims you need, order them from Precision Shims Australia, or order a Hot Cams shim kit in the right size from the US.

    If you can afford to have the bike off the road (or are happy to put it back together until the shims arrive) I would have a crack.
  3. I have known countless backyard mechanics who have treated shim replacement as boringly routine so I'd say that your local bike mechanic is full of shit.
  4. Let me know how you get on. This is one of the Jobs I need to do as-well and haven't built up the courage just yet.
  5. I have done valve clearance checks on my VFR400 and the Suzuki Across and I am just a backyard mechanic. It is simple, just fiddly and tedious. Depending on the engine design/configuration, the task can be annoying or simple. For example, the VFR400 is much much easier compared to the Across in changing the shims due to the fact that you can change the shims without removing the rocker assembly, camshaft and timing chain tensioner (V4 don't have timing chain btw so even easier).

    Seeing as you have already worked with engines before, I don't see how a valve clearance check can be anymore difficult for you. The only difficult part I can foresee is getting replacement shims if you had to change them.
  6. $15 per shim? are they gold?

    When i did my shims on the blackbird they were about $2. Easy enough to do, do you have a feeler gauge for measuring the gaps? I do not have your experience with engines but i managed to do mine. Get a good manual that tells you how to do it etc.
    Oh and do not open the homebrew before you start.
  7. Oddly enough, I never found out... I found some Hotcams one's for $5ea at the 300th shop I went to.
  8. Rubbish. It's not a hard job, especially if you're already done it on adjuster-type valves. It just takes a lot of time to do correctly, any you need to be very careful that you get the engine timing right, loosen/fasten the camshafts in a gradual manner, etc.

    I say "do correctly" because I've noticed that some people think that because feeler gauges generally go up in increments of 0.05 around the range that their valves will be set at (eg. 0.23 +- 0.03), that resolution will be OK for measuring and setting the clearance. I'd suggest combining feeler gauges to measure your valves to the 0.01mm. That way, you'll know at the end that your valves are now comfortably in spec, not right on the outer limit, and you'll probably do less work next time.

    Regarding the cost of shims - I think I ordered them for about six dollars each from the Honda dealer, and I had them in my hands the next day. There is a "universal shim calculator" available for download somewhere that makes the task of rearranging and purchasing shims an absolute breeze - let me know if you can't find it, because I can send it to you.
  9. Finally got around to opening up the XJR13; biggest problem was getting access to enable the removal of the head cover to get to the cam lobes. (Air Induction System :banghead: Mr Yamaha... give us an extra 10mm please!!!)

    The bike is an 2007 XJR1300 with 22,500km on the clock. I found 1 x intake and 3 x Exhaust clearances out of spec, so now waiting on a valve shim tool to arrive, to get them out.

    Is the Valve Pad Selection Table, mentioned in the manual, specific to the bike or just a generic table???
    (the Valve Pad Selection Table mentioned is not included in the manual :confused: )
  10. can you not remove them with a magnet? I use a telescope magnetic used for picking up dropped nuts and bolts etc.

    Yes the space can be a bit tight.

    The table is generic and it will calculate the shim required to give you the required clearance. It is a simple bit of maths.
  11. Yeah mate, planning to use a magnet to pluck them out, but I need to hold the valves/springs down to get some space to lift them out.
    I have the correct tool on its way; although, I know some just use a screw driver to hold the buckets down.

    Thanks also about the table.. cheers(y)
  12. Just a tip. Before you wind the engine over by hand to open a particular valve & fit the special tool, use a screw driver to rotate shim bucket so the cut away/notch in the shim bucket is where you can get access to it. Otherwise if it is off to one side then you can't get a screwdriver in there to lever the shim out of the bucket. The special tool, once fitted, usually jams the bucket in one position & prevents you from rotating bucket until notch is in favourable position. The shims are sometimes a tight fit in the bucket, but also the oil makes them stick with suction. A magnet by itself is sometimes not strong enough to draw them out of the bucket, but usefull in removing them once they have been prised out with a small flat blade screwdriver.
  13. Tinkerer; Thanks for the tip.

    I was also told to only bother changing the 'shims' that were tight and not to bother with the clearances that where just above the recommended spec, as these will tighten. :confused:

    What are your thoughts about this???
  14. Within reason, a slack clearance will do no mechanical damage, although it will have a marginal effect on performance because it reduces valve duration. If a clearance is a gnat's bollock over spec you'd generally get away with leaving it.

    However, given that you've got the engine open anyway and you'll be toddling along to the shim shop, why do half a job?

    Once you've got the shims out of the out of spec valves you may be lucky and find that you can juggle the existing shims around and get more of the valves within spec, leaving only one or two additional shims to buy. OTOH, you might not.
  15. I'd agree as a general rule. But there are the rare exception with some engines that can have ticking noises when hot, with the valve clearances just a little loose. If this were the case you could try shimming them to the tighter end of the tolerance, to see if that will quieten them down.

    It also depends on your definition of 'tight'. If I'm correct, the specs for your bike is 4-6 thou (0.11-0.15mm) inlet, and 6-8 thou (0.16-0.20mm) exhaust. Now if your 4 thou feeler gauge will still fit between the inlet cam & shim, but with a bit of drag, then some may cosidered this tight, but still within specs, and changing shim perhapps not necessary.

    On the other hand, if a 4 thou feeler wont fit, but a 3 thou is a loose fit, then I would say that this is definately tight, and you would be justified in changing a shim.

    However keep in mind that manufacturers usually only sell shims in 2 thou increments. So if you did change a shim
    in this circumstance, the clearance would go from a tight 4 thou, to a tight 6 thou. From the tight end of the specs, to the loose end of the specs. In this circumstance you could almost flip a coin as to which way you would prefer to have it.

    There are some other things to consider:

    Exhaust valves tend to get very hot, and they are cooled every time they close, transferring some of their heat through the valve seat into the head. The tighter the clearances means less time the valve is closed. The looser the clearance the longer the valve remains closed. So for an exhaust valve, If I had to choose, I would run it at the loose end of the specs, because I'm a conservative and like to play it safe.

    Inlet valves do not suffer from heat as much as the exhaust, so being a little tight is less of an issue for them. If you intend to check clearances regularly, then you could leave it a little tight. But if you don't plan on ever checking them again & want to ride off into the sunset with confidence, then I would set the inlets at the loose end of the specs as well.

    Most of the time the manufacturers set their valves from the factory at the loose end of the specs. They however can get them spot on, because they have shims in 1 thou increments.

    Having the valve clearances tight takes maximum advantage of the camshaft lift & duration, giving you the most power the cam is capable of producing, and moving it further up the rev range. Having the valve clearances loose
    shortens the valve duration, which is better for low rpm running & economy. (This may however be splitting hairs & may only detectable on a dyno.)

    On a side note. I was a little surprised that you would need to check, let alone re-shim the valves with such low k's on the bike.
  16. thanks for the invaluable info & opinions (y)
    As I said earlier, I am a novice mechanic but enjoy trying to fix things myself.

    I too was surprised that the clearances were out of spec at only 22K. (thought I'd be lucky)

    I have no rides planned for this bike coming up, so I have time. I am just waiting on a shim tool, then I'll get on with the job, so I'll post up my next move then.
    Once again, thanks for your help
  17. Finally got the job done (y)

    I found 4 clearances were out of spec, with some shuffling around of most of the shims, I have managed to get all the clearances back in spec without buying a single shim. (although, I will order a couple to keep in my kit, for down the track)
    Biggest delay: waiting for the shim tool to be delivered (problem when you live in the sticks)
    Biggest pain in the A*se: getting the 'Air Induction System' in and out, so to get access to the cam cover.
    Best tip: write down all the shim sizes and locations for future reference.

    just finished my 20k service for around $100. Includes brake/clutch oil, engine oil & filter, and my shim tool ($60)
    Only part I haven't done is the EFI service; however bike seems to be running alot smoother now.

    thanks for the tips all.
  18. Well done,

    We told you it was possible.
  19. Not sure what would be included in an EFI service. All I can really think of is balancing the throttle bodies which should be pretty much like balancing a set of carbs. Otherwise there shouldn't be much to touch. I suppose getting the injectors ultrasonically cleaned wouldn't do any harm but it certainly shouldn't be necessary at <100,000 km. Oh yeah, and I expect there's a fuel filter somewhere but, in my BMW EFI experience, if your fuel is reasonably clean (and it is in most of populated Australia), you can leave it for many times the recommended interval without the bike grinding to a halt.
  20. An excellent result!