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pulling off the heads for the first time

Discussion in 'Technical and Troubleshooting Torque' started by lightcycle, Apr 20, 2008.

  1. hi,

    I'm kind of at the beginner intermediate skill level mechanically and am thinking about taking the heads off for the first time ('89 Spada). It's running fine and stuff, I'd just like to clean out the cam chain tensioner piston and get rid of some top end rattle.

    Is it a bad idea to pull the heads off if the bike is otherwise running fine? I've been given the advice that if it's not broken I should leave it the fck alone (esp seeing as most bikes have a rattle of some sort), but that seems a bit limp.

    I've got all the manuals and stuff, from the diagrams it seems pretty straight forward.

    leave well enough alone or get into it? opinions?
  2. If it aint broke don't touch it! you will only create problems. :roll:

  3. Someone told you there is a camchain tensioner piston which needs cleaning out?

    How much time have you allocated for this job?

    You have a spare bike or car?


    Trevor G

    PS I do have a more complete response to your post but I am interested to see how you are planning for this little "venture", to see if you have any idea what time and effort is involved, to see if you have actually thought it all (or any of it) through....
  4. make sure u replace the flux capacitor while ur in there.
  5. hey mate,

    I was giving it a full day. start early morning and have it back together by evening.

    The service manual talks about servicing the automatic cam chain tensioner and gives a rough procedure on how to remove and clean it.
    It's not so much a piston, more an oil reserve that sits at the bottom of the tensioner spring applying pressure. Apparently the drain holes at the bottom get filled up with gunk (its a twenty year old bike), affecting how the cam chain tensioner operates and leading to the chain losing tension. Pull out the tensioner, clean out the piston/reserve, hopefully lose the rattle.

    I'm fine on PT if things dont go right.

    I'm not being a smartarse, but what kind of problems?

    If I'm being stupidly naive, go easy on me. :oops:
  6. Nothing specific, just being generic. Maybe something else will need adjusting if it’s disturbed. Remember Murphy's Law will prevail! ](*,)
  7. Don't forget that even if you don't f*** up the valve timing and destroy
    your engine, that you will need a bunch of new gaskets including
    head gaskets, and that alone will cost you a couple of hundred dollars.

    Most cam chain tensioners are accessible from the outside of the engine.
    Can you do that instead? If not, I wouldn't mess with it because it's a lot
    of money, effort, and risk, for slight or no benefit.
  8. Hmm are you sure it's actually the heads you want/need to be removing, and not just the camshaft covers?
    Removing the heads is a pretty major project since as mentioned you will need new gaskets and if you stuff something up you could end up with an engine that is completely useless (ie stuff all compression).
    Removing cam covers is a lot more common since that's needed for adjusting the valves. To do it right you may still need a new gasket (though this will be a lot cheaper than the one for the engine head since it doesn't have to retain as much pressure). Cam chain and tensioner should be accessible without having to remove the head (though it is a Honda so anything is possible) - but if you're going to go to the effort of removing the cam covers it's probably worth doing the valve clearances at the same time and possibly even replace the cam timing chain (depending on how worn it is).
    Given it's not something you've done before though I wouldn't consider it if the bike is your only means of transport - never know what parts you might need (especially valve shims).
  9. thanks guys. I think for the moment I'll just pull the camshaft covers off and see what I can see, not muck around with anything unless it looks straightforward.

    The service manual suggests that you might need to pull the heads off to get at the tensioner, but it's a bit hazy, so jd might be (and probably is) right.

    I'll have a go next weekend, let you know how I go.

    never going to learn anything if I'm too scared to do get into it. :wink:

    thanks again,
  10. Is there a Netrider Spanner Day scheduled in the area, perhaps you could take the bike along and get some older heads involved (no pun intended)?

  11. Top end rattle is likely to be caused by a worn timing chain, rather than a worn tensioner.

    You do not need to remove the heads to access the tensioner. You only need to remove the exhaust camshaft on each head. There are two tensioners.

    If anything is worn it could be the slipper which actually is held against the chain under pressure from the tensioner.

    What mileage is showing on the bike?

    It would be bad to pull the heads off, since that is one or two steps further than you need to go.

    I would suggest reading the manual(s) first ;-) and then asking the questions that are not straight-forward.

    Page 9-2 of the Spada manual shows the location of the tensioner and page 9-3 has the steps involved. If you are not familiar with these procedures I agree that it might not be clear. In that case, better leave it alone.


    Trevor G
  12. Leave the head on. Pull the cam cover off and measure the clearances.

    Buy the replacement shims and a new cam chain if required. Probably need new camchain guides as well. Worth looking at anyway. They could be worn out.
  13. No shims needed - screw and lock nut adjusters.


    Trevor G
  14. heya,

    well, I pulled the rocker covers off and had a look, I chickened out on doing anything about the cam chain, maybe wisdom took over for a second.

    I redid the valve clearances, they were all set differently!

    The spada has some nice markings around the crankshaft to tell you where TDC is for each cylinder:

    I'll admit, I fckd up and used the clearances stated in the little manual that came with the bike rather than the service manual. While the service manual (in which I had trouble actually finding the numbers until today) says it should have 0.15IN and 0.20EX, the manual I worked from says 0.17 for both IN & EX which I think is just plain wrong. So the INs are loose and the EXs are tight. :(

    It's running fine (better than it was, really), it's got a lot of valve noise making it sound like I've got a footy card in the spokes of a bmx. :oops: I'm learning. No riding till I get it sorted out, obviously.

    TrevorG: the bike's got 27,000 on it. I think I might have to remove both camshaft holders to get the tensioner out. Here's some photos:

    With the radiator removed:
    you can see the camshaft holders, there's a bar running between them that has another bar coming off it that bolts onto the cam chain tensioner mount.


    I think I'll leave it until I get a bit better.

    Thanks for your help everyone, :)
  15. Here's a couple of tips for you when checking valve clearances.
    Leave the spark plugs in the heads. Don't remove them. Reason -any bits of carbon on the spark plug threads may fall & become lodged between the valve & seat throwing your carefully measured clearances way up the shit.
    Buy yourself a set of tapered tip IMPERIAL feeler gauges. Yes I know it's a Japanese bike & is constructed with all metric fasteners etc etc but you will get a lot better results with Imperial feeler gauges. Reason -Metric feelers step up by 0.05mm at a time. Or 2 thousandths of an inch. Imperial feelers step up 1 thou at a time. Your bike recommends 0.17mm clearance. Metric feeler gauges have only 0.15 or 0.20 steps. So you are only really guessing. Simply divide the metric measurement by 25.4 to give you the imperial equivalent. In your case 0.17/25.4 =0.00669. Close enough to 7 thou. Not totally precisely exact I know, but still a lot closer than guessing between 0.15 & 0.2mm. Yes, very anal I know but believe me, when you have to pull camshafts to change shims -you want to get it right first time round let me tell you :grin: :grin:
  16. Good work...

    15 and 20 are correct.

    They need to be a tight 15 and 20. You should only just be able to insert the gauge. Pull up on the tappet adjuster at the same time.

    After you insert the correct gauge tightly, use the next one down to see the difference - it should be a lot looser. The correct gauge must be able to slide all the way through the tappet gap, and then some. But it should be tight. The next size up should have no chance of getting a look in.

    A sloppy "tightness" will lead to noisy tappets. They become slappets if you don't do it right. ;-)

    Did you see any grunge in there? I didn't, from your pics, and that is a perfectly good reason to leave the camchain tensioners alone.

    Did I say leave the camchain tensioners alone? I meant, "Leave the camchain tensioners alone!!"


    Trevor G
  17. Re: Good work...

    Nah, it was spotless in there.

    I'll leave them alone, no worries! :oops:

    I'll let you guys know how I go this weekend. Another spanner weekend for me. :grin: :grin:
  18. fwiw, metric feeler guages should be able to make any gap you need, just make sure they are clean and sandwich a couple together to get what you need - they have enough range in the thin ones to do this.
  19. Perhaps you can help me with the required metric size feeler guages for my bike. Inlet spec is 0.12-0.18mm Exhaust is 0.21-0.27mm. How do I know if the inlet has gone below 0.12 or the exhaust has gone over 0.27?
  20. That'd be pretty easy, and I thort a smart guy like you would know how to do it.

    15 and 25 are close enough.

    10 and 20 are too small (take a measurement with those just to make sure) and 20 and 30 are too big. It's easy once you know how... ;-)

    And if you didn't know, there is no performance advantage in having the tappets a mil or two tighter or looser - it is not a "you must get this right on the knocker or else" sort of adjustment.

    But you knew that...and while your earlier post is interestingly correct, you might just be getting a little pedantic about it. ;-)


    Trevor G