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valve clearence adjustment


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Graham NZ
23 hours ago, Graham NZ said:

Has anyone here carried out checks more than once and if so had the clearances changed in 12,000km?

 

This is a question we all would benefit from getting answers to.

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Hi, Not disagreeing with what has been said here but I would like to try to clarify some misleading/incorrect descriptions that can be found in various videos, threads and in particular an older

The following may help budding tappet adjusters.   Checking and adjustment is recommended at 12,000km intervals but is that really necessary?  Check out other owners’ findings.   I

The design of the valve cover disappointed me.  No positive means of locating it in place other than the three wavering long screws.  Getting those screws to locate into their threaded holes caused me

Graham NZ

Buell Lightnings with modified HD engines were made until late 2009.  HD guarantee to supply parts until late 2019.  The parts I've bought were readily available and cheap. 

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Graham NZ

The following may help budding tappet adjusters.

 

Checking and adjustment is recommended at 12,000km intervals but is that really necessary?  Check out other owners’ findings.

 

It’s a fiddly job and took me about three hours of working on my knees.  A bike lift would definitely help.  A third hand would make removal and refitting the radiator easier; two hands available to deal with the two clips and fan plug behind the radiator while the otherwise disconnected radiator is held by a second person.

Allegedly the job can be done without disconnecting and removing the radiator but I don’t recommend that.

 

Radiator removal and refitting

  • Remove the lower plastic engine cowl.  Two screws.
  • Remove the radiator cap retaining screw but not the cap at this stage in order to slow initial draining.
  • With catcher tray below, remove the engine’s coolant drain plug up behind the exhaust manifold.  10mm socket on extension bar.  Now remove the radiator cap and allow the system to drain.
  • Disconnect the two hoses and the overflow hose from the radiator.  Expect a bit more coolant to drain out.  Clip the lower hose back out of the way.
  • Remove the lower radiator locating bracket.  One screw.  10mm spanner. Remove the left screw from the top radiator holding lug and slide the radiator out a bit to the left.  At this point have a helper hold the radiator a bit forward to give better access to the two plastic clips and the fan plug mounted on a lug on the left side of the fan housing.  Long nosed pliers make removing the clips easy.  Squeeze the lower part of the plug and pull down.  Now the radiator is free to be removed.  I back-flushed the radiator with a hose.
  • When all is refitted, refill the radiator with 50/50 de-mineralized water and silicone-free anti-freeze, fit the radiator cap run the engine for a few minutes, stop the engine for another few minutes and top up the coolant.  I also drained and refilled the overflow tank.

Rocker cover removal and refitting

  • Remove the three long retaining screws.  To break the seal, tap the rocker cover sideways with a soft hammer and remove the cover and sealing ring.  Inspect the ring.  Mine was perfect.  Replace it if damaged or more than a few years old.  Clean the ring, joint faces and outside of the cover.
  • When refitting the cover have the sealing ring in place on it.  I don’t recommend using a sealant on the ring because it’s likely to be smeared about when refitting the cover.  The ring is nicely designed with three sealing ridges and the flat landing face is broad.
  • Put the three retaining screws through the cover and then lift it gently into place but held about 15mm above the engine surface and then ‘see’ each screw in turn into it’s threaded hole.  Otherwise it is difficult to get the un-guided screws to find their holes.

Tappet adjustment

  • Remove the two plugs on the left of the engine and both spark plugs.  With a 17mm socket and ratchet rotate the engine slowly clockwise until a timing mark with 1 or 2 beside it lines up in the forward hole.  At this point the tappets of all four valves of the relevant cylinder should be felt to have some movement but only the front exhaust ones of the other cylinder can be moved.  Adjust only the four tappets on the cylinder with movement at this stage and repeat for the other cylinder when the next timing mark aligns.
  • A lot of mucking about can be indulged in when adjusting tappets but I like to keep it simple.  I checked the inlets for 0.18mm and the exhausts for 0.28mm and if loose or tight against a feeler gauge, adjusted them.  To do this, loosen the locknut with a 10mm ring spanner, open the screw a little if necessary, insert the feeler and close the screw until it just holds the feeler.  Hold the screw and carefully tighten the locknut. Remove the feeler and check the adjustment again.  Sometimes adjustment is reduced a little as a locknut is tightened and if so repeat the procedure.
  • In the case of my 12,000km bike all four inlets were too tight with about 0.10mm clearance, two exhausts were spot on and the other two were marginally tight.  I could not detect any difference in sound after the adjustments and IMHO slight clearance discrepancies are unimportant on this engine.  

 

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Graham NZ
On 8/4/2018 at 08:18, Graham NZ said:

Has anyone here carried out checks more than once and if so had the clearances changed in 12,000km?

 

Still waiting for a reply to this, or has no one carried out checks more than once?  Without evidence that clearances have changed in 12,000km it's fair to assume that the incorrect clearances reported so far were as set at the factory.  If that is the case it would be worth having clearances checked early in a new bike's life.

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On another forum there are reports of 0.10 inlet clearances, which is what they were on my bike.  Co-incidence?

Edited by Graham NZ
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Dunnster
17 minutes ago, Graham NZ said:

 

Still waiting for a reply to this, or has no one carried out checks more than once?  Without evidence that clearances have changed in 12,000km it's fair to assume that the incorrect clearances reported so far were as set at the factory.  If that is the case it would be worth having clearances checked early in a new bike's life.

Insert other media

On another forum there are reports of 0.10 inlet clearances, which is what they were on my bike.  Co-incidence?

Checked mine at 16,000 miles and all but one were tight, reset the clearances to spec, checked again at 24,000 miles and all were in spec. I will check again at 32,000 miles. Mine is a 700 with 8,000 mile checks. You seem to have a 750 which I thought Honda changed the frequency of valve inspection to every 16,000 miles. 

With you checking yours at 12,000km you seem to be on the 700 schedule? (12,000 km just under 8,000miles) but seeing as yours were tight it seems like it was worth it. 

Edited by Dunnster
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I suppose from the evidence thus far, it would be interesting to learn what the clearances were (or are generally) from the factory, given that Honda don't seem very bothered about build quality on this particular model

1 hour ago, Dunnster said:

Checked mine at 16,000 miles and all but one were tight, reset the clearances to spec, checked again at 24,000 miles and all were in spec. I will check again at 32,000 miles. Mine is a 700 with 8,000 mile checks. You seem to have a 750 which I thought Honda changed the frequency of valve inspection to every 16,000 miles. 

With you checking yours at 12,000km you seem to be on the 700 schedule? (12,000 km just under 8,000miles) but seeing as yours were tight it seems like it was worth it. 

 

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Graham NZ
23 hours ago, Dunnster said:

Checked mine at 16,000 miles and all but one were tight, reset the clearances to spec, checked again at 24,000 miles and all were in spec. I will check again at 32,000 miles. Mine is a 700 with 8,000 mile checks. You seem to have a 750 which I thought Honda changed the frequency of valve inspection to every 16,000 miles. 

With you checking yours at 12,000km you seem to be on the 700 schedule? (12,000 km just under 8,000miles) but seeing as yours were tight it seems like it was worth it. 

 

Thanks Mike.  Just as I thought, your findings confirm suspicions that the clearances ex-factory are probably the problem.  If so it would pay to have them checked on new bikes early on.

 

The manual I have is for the 700 models so I don't know how often my 2014 750 SD should have it's tappets checked. As my bike is almost four years old I needed to change the coolant so going on to the tappets made sense.  In light of your post I'll check them again in three years when it's time to change the coolant again.  If I'm still riding bikes then that is.

Edited by Graham NZ
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Dunnster
28 minutes ago, Graham NZ said:

 

Thanks Mike.  Just as I thought, your findings confirm suspicions that the clearances ex-factory are probably the problem.  If so it would pay to have them checked on new bikes early on.

 

The manual I have is for the 700 models so I don't know how often my 2014 750 SD should have it's tappets checked. As my bike is almost four years old I needed to change the coolant so going on to the tappets made sense.  In light of your post I'll check them again in three years when it's time to change the coolant again.  If I'm still riding bikes then that is.

Regarding the valve clearance check, I'm sure Honda changed the frequency from 8000 miles to every 16,000 when the 750 was released. I can understand Honda doing that as mine were in spec after my last check, I'm sure after obtaining some info from mechanics they decided to up the mileage frequency. If mine are still within spec at my next inspection I might leave 16,000 miles between checks. But as I change the coolant at the same time, its a no brainer to check with the radiator out of the way.

Personally, I think the first valve inspection is one of the most important and shouldn't be missed, new engine  running in with all the internals wearing and bedding in, will create a bit of movement, plus a lot of loosening and tightening of components. 

Im sure you've got many more miles of riding ahead of you. 

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Reckless_Rat

Hi,

Not disagreeing with what has been said here but I would like to try to clarify some misleading/incorrect descriptions that can be found in various videos, threads and in particular an older electronic Service Manual.

 

It looks like there may have been some confusion with the positioning of the crankshaft & camshaft in readiness for the valve clearance adjustment.

 

Sorry if all this is obvious but I haven’t seen it explained like this elsewhere and thought it might be useful for someone who is doing this job for the first time:

 

In an engine with a Four Stroke cycle, there are two occurrences when each piston is at Top-Dead-Centre (TDC). So it is not sufficient just to get a cylinder aligned to TDC. The crankshaft goes around twice for a single turn of the camshaft. One TDC is when the exhaust gases have just been expelled and the input charge is about to be drawn in. – This is NOT the TDC you want when setting the valve clearances as the valves may not all be fully closed. The TDC you need for the valve clearance adjustment is a full 360 degree turn of the crankshaft (= 180 degree turn of the camshaft) later, at the beginning of the power stroke, when the valves on the given cylinder are all fully closed. So in addition to the TDC marks under the left hand crankshaft cover, Honda have also provided a timing mark on the right hand end of the camshaft under an inspection cover. Unfortunately there appears to be an error in an old electronic PDF Service Manual which shows this camshaft sprocket mark lined up against the upper cylinder head index line on the engine casing, whereas from inspection and other sources (paper service manual, watching the valve sequence, previous posts, etc.) the camshaft index mark you should align to is the lower one (labelled [4]).

If the valve adjustments are already roughly within their normal operating range, you would also be able feel a slight gap in the rocker arm movement at this TDC.

 

BTW: I checked mine earlier this year (~13,000 miles) and I found the inlet valve clearances had all been slightly on the tight side but at the edge of tolerance (0.15 instead of 0.17) and all the exhausts slightly tighter than spec (around 0.20 instead of 0.28). This seems similar to what others have reported.

Readjusted all and seems fine.
 
Usual disclaimer!
 

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Scootabout

It seems there's some evidence that these bikes often come out of the factory with incorrectly set clearances. Surely that ought to be a valid warranty claim? If you had them checked on day one and they were out, could you get the cost of the check and adjustment refunded?  Obviously hardly anyone would actually do that, but it's an interesting question, no? 

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Reckless_Rat
39 minutes ago, Scootabout said:

It seems there's some evidence that these bikes often come out of the factory with incorrectly set clearances. ...

Is there? - Or could it be that there is an initial run-in/burn-in period for a while after they have been correctly set at the factory ?

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Graham NZ

Because screw and locknut tappets are just as easy to get wrong as right, I vote to have them checked early in a new bike's life.

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embee

Out of interest I did a 700 Deauville today. It was about 40k km (25k mls) since last done, we generally reckon on around 20k mls being sensible for the various Deau engines based on field experience from many folk. All were slightly loose, by similar amounts, indicating a pretty well engineered and controlled system. The valve gear is similar in concept (rocker above cam) but different to the NC in significant ways, Deau = one rocker with 2 locknut adjusters for the 2 inlets/exhausts etc and fixed pad followers, the NC is roller follower and individual rockers for each valve so quite different in detail.

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