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Valve check interval


SinNH

Valve adj frequency  

90 members have voted

  1. 1. Did you check/adjust your valves before 30k miles?

    • yes
      37
    • no
      53
  2. 2. If yes on question one, were they out of spec?

    • Yes
      12
    • No
      23
    • So close I left as is
      3
    • not applicable
      52
  3. 3. When will you check again?

    • +15k
      16
    • +25k
      32
    • probably never
      42


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  • Member Contributer

Bought bike with 18K on it PO said valves checked at 16K. Checked 'em myself at 40K. Most EX tighter than min spec. Shimmed to spec, and re-checked at 60K. EX at the tight end of spec so no shimming. Will re-check at 80K.

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  • Member Contributer

Bringing an old topic back but, how many have wet sanded the shims instead of replacing?

Me. But only if I didn't have a shim...My friends and I have a box of shims we trade and share....

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  • 2 weeks later...
  • Member Contributer

I didn't wet sand mine, but did take them to a friend of mine to have them ground to the spec I wanted.

Kind of interesting that over 30% of the bikes that were checked before 30,000 miles were out of spec.

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Just completed my 5th Gen valve check at 107,000 kms. Not sure if it's ever been done before.

Exhaust,

1 of .007

4 of .009

3 of .011

Intake

1 of .003

2 of .005

4 of .006

1 of .007

I tried to wetsand one of the shims. After about 30 seconds, I couldn't measure any change so I just exchanged them at the Honda dealer locally for $6/shim. I may have persisted in the sanding but I was a little concerned about getting the surfaces out of parallel.

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Good thinking. You don't have to take much off, but it would be pretty easy to get it un-parallel, not a good thing.

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Having some issues with getting my 2000 running again. I put it all back together and it will start only if I hold the throttle about half way open, won't idle, and won't rev. It looks to me like I did everything correctly as far as installing the cams but there is something in the manual that I don't understand. It states:



"Turn the crankshaft clockwise and align the "3T" mark on the ignition pulse generator rotor with the index mark on the right crankcase cover. "



That part makes perfect sense, it's bringing piston 3 to top dead center.



It then states:



"Make sure that the No. 3 piston is at TDC (Top Dead Center) on the compression stroke.



Here's what I don't understand. If the index mark on the pulse generator is lined up with the mark, how is it even possible that piston 3 is not at TDC, isn't that what the mark does? The only thing I can figure is that it's a redundant statement. With #3 being the first set of cams to be installed, I understand that there is no TDC of compression stroke VS TDC of exhaust stroke until at least one set of cams is installed.



Surely it's not meaning that the mark is only an approximation and you must use a piston "feeler" through the spark plug hole to determine the exact TDC.



Any suggestions?


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  • Member Contributer

Might be 180 out. It takes 2 revolutions of the crank to complete 4 cycles. Piston could be on compression stroke tdc or exhaust stroke tdc. Hope this makes sense.

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Might be 180 out. It takes 2 revolutions of the crank to complete 4 cycles. Piston could be on compression stroke tdc or exhaust stroke tdc. Hope this makes sense.

I see what you're saying but with no cams installed, there is no difference between TDC compression and TDC exhaust. There's just a crankshaft and rods and pistons in an aluminum shell. It's only the cams pushing the valves that makes it compression TDC VS exhaust TDC.

Manual instructions say put the crankshaft at #3 TDC then install rear cams with marks out, then rotate crankshaft 1.25 turns clockwise and install front cams with marks facing out.

Is there anything that makes TDC compression VS exhaust before cams are installed?

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I've got a 95 so cam installation might be a bit different. For starters you line up the T1 mark to install the rear cams and the T2 mark to install the front cams. On my cams there are 2 sets of marks: lines which the manual calls timing MARKS and arrows called timing ARROWS. The marks are used on the rear cam installation and the arrows are used for the front cams. If you used the wrong ones your timing would be out. But if that was the case it probably wouldn't even start and you woukd have noticed valves hitting pistons when you turned it over by hand.

But you are right in that when front and rear cams are removed, there is no TDC compression stroke yet. So it is odd that note is in there. My manual only makes that distinction when only the front or rear cams are removed, not both.

If you are sure the cams are installed correctly I would guess a fuel or injector issue, or maybe a throttle position sensor issue.

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Having some issues with getting my 2000 running again. I put it all back together and it will start only if I hold the throttle about half way open, won't idle, and won't rev. It looks to me like I did everything correctly as far as installing the cams but there is something in the manual that I don't understand. It states:

"Turn the crankshaft clockwise and align the "3T" mark on the ignition pulse generator rotor with the index mark on the right crankcase cover. "

That part makes perfect sense, it's bringing piston 3 to top dead center.

It then states:

"Make sure that the No. 3 piston is at TDC (Top Dead Center) on the compression stroke.

Here's what I don't understand. If the index mark on the pulse generator is lined up with the mark, how is it even possible that piston 3 is not at TDC, isn't that what the mark does? The only thing I can figure is that it's a redundant statement. With #3 being the first set of cams to be installed, I understand that there is no TDC of compression stroke VS TDC of exhaust stroke until at least one set of cams is installed.

Surely it's not meaning that the mark is only an approximation and you must use a piston "feeler" through the spark plug hole to determine the exact TDC.

Any suggestions?

You've got it right, the manual isn't being clear, or maybe trying too hard and being unclear. Either way, if it starts, I'd say you have another issues, sensor, fuel or maybe, a cam(s) went in a tooth off. Start with the connectors on the outside first and work back to checking the cams.

BTW, I always do stick a long screwdriver in the spark plug hole and check that it's "topping out" as the marks line up.

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Having some issues with getting my 2000 running again. I put it all back together and it will start only if I hold the throttle about half way open, won't idle, and won't rev. It looks to me like I did everything correctly as far as installing the cams but there is something in the manual that I don't understand. It states:

"Turn the crankshaft clockwise and align the "3T" mark on the ignition pulse generator rotor with the index mark on the right crankcase cover. "

That part makes perfect sense, it's bringing piston 3 to top dead center.

It then states:

"Make sure that the No. 3 piston is at TDC (Top Dead Center) on the compression stroke.

Here's what I don't understand. If the index mark on the pulse generator is lined up with the mark, how is it even possible that piston 3 is not at TDC, isn't that what the mark does? The only thing I can figure is that it's a redundant statement. With #3 being the first set of cams to be installed, I understand that there is no TDC of compression stroke VS TDC of exhaust stroke until at least one set of cams is installed.

Surely it's not meaning that the mark is only an approximation and you must use a piston "feeler" through the spark plug hole to determine the exact TDC.

Any suggestions?

You've got it right, the manual isn't being clear, or maybe trying too hard and being unclear. Either way, if it starts, I'd say you have another issues, sensor, fuel or maybe, a cam(s) went in a tooth off. Start with the connectors on the outside first and work back to checking the cams.

BTW, I always do stick a long screwdriver in the spark plug hole and check that it's "topping out" as the marks line up.

Looks like you came to the right conclusion. Today I was looking at some pictures of the cam markings I took last night and was sure the rear intake cam was off by a tooth. I checked it when I got home and came to the same conclusion so I removed and relocated it. Put it all back together and bingo, ran it very briefly as no coolant but it sounds normal again. Amazing how much difference one tooth makes.

Thanks to everyone for the suggestions.

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I have never checked my valves on current 5th gen, had 64k kms on clock as I buoght it, now it has 84k kms, but might do it as the engine has got more vibrations by time. I did it once on my old -87 750F, and needed to adjust then, but that didn´t need any shims as scruv adjusters on it.

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  • Member Contributer

Just a report back on the shim job, bike runs better than ever although I did also change plugs. 107,000km and runs like a scalded cat.

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That's great, though I have to admit that I didn't notice a difference after my valve adjustment, which also included new plugs, oil & filter and coolant.

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That's great, though I have to admit that I didn't notice a difference after my valve adjustment, which also included new plugs, oil & filter and coolant.

Mine was running with an engine vibration which was the reason the whole process started. First thing I checked was the plugs, finding one loose and hammered out plug threads needing repair. When the fairings were off I noticed a coolant leak, thus took the airbox and throttle bodies off. When everything was apart I figured I may as well do the valve clearance check. Also cleaned the air filter so all of these together made a noticeable difference.

Did change the coolant at the same time and also the thermostat and the two short tstat housing hoses as one was looking very bulged.

I'm just glad to have it all back together.

Do you remember how many valves you adjusted and how far out the worst ones were?

BC

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I had 3 valves that were out of spec: #2 intake, #2 & #4 exhaust. They were all tight by 0.001". Honda shims come in 0.025mm (or approx. 0.001") increments so I dropped 2 shim sizes to put them back into middle of range. I didn't have a micrometer to measure anyway so it was convenient.

I had 8 valves that were at the tight end of spec: #1 intake, both #1 exhaust, #2 intake, #2 exhaust, #3 exhaust, #4 intake, #4 exhaust. So 8 extra shims to put them back to middle of spec. Afterwards someone suggested putting them to loose end of spec as the tendency on my valves were to get tighter. The theory being that they would stay in spec longer.

Anyway, the curious thing was that after swapping the shims I re-measured and found that some valves that were okay before were now tight! I turned the engine over several times and with the same results. So luckily with the shims I had taken out I could redo all the *now* tight valves. I had become well-practiced in removing the cams so that's what I did. So now they are all measured in spec. Did you run into this?

At least it runs no worse than before, and I didn't do a carb synch afterwards either. So when people say that when you do it yourself, you know it's done right, the corollary to that is when you do it yourself, you know who to blame.

Edit: this was on 95 with 166K km. Last check was at 100K km.

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I ended up with two exhaust valve that were really loose after the new shims. I ended up going almost back to where I started on those two. I figure I must have measured with the cam out of position the first time.

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  • Member Contributer

I had too many that were tight after for it to be a mistake on measurement. But I figure at best they are in middle of spec as measured or at worst, the loose end of spec.

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  • Member Contributer

Measuring clearances is a learned skill, and dependent on your style of gauge. It is a an exact science in theory only not in practice. As long as you have some clearance you are good. The problem is deciding just how much clearance to leave to get you to the next check. For this you need a recorded history of movement which is something those who have never checked don't have.

Personally I'd rather do clearance checks/shim swapping than used engine swapping, but to each their own.

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