16k Valve Check - Observations

[okmurdog]

I just performed the 16k valve check on my bike....twice.

Let me explain (a bit long, but unusual) -

I first checked the valves at 16,050 miles. During this check, I found three valves out of specification, and several others were technically in specification, but were close to the 'low' side. I measured ALL of the valves using two different feeler gauge sets (English and Metric). I first performed measurements on all valves using the English set, and started all over again using the Metric set. The English set is graduated in 0.001 inch, whereas the Metric set is graduated in 0.01 mm. Both sets of feeler gauges confirmed the out of spec valves.

During this first inspection, I rode it home from work on a Friday afternoon & pulled the tupperware. I performed the valve clearance inspection the following day. Ambient temperature in the garage was around 48? F.

I ordered a Hot Cams shim kit, and several other parts recommended by Honda that should be replaced when the cams are pulled.

While waiting on the parts to arrive, I was somewhat bothered by the findings of three valves out of spec, and several valves close to tolerance. I have read many accounts of folks finding the 16k valve check in tolerance, with no adjustment necessary.

I started thinking of any scenarios which might cause the valves to be out of specification. I ride my bike nearly every day, mostly to commute back and forth to work. The trip is a combination of 7 miles of country roads (with stop signs every mile), 8 miles of 55 MPH non stop roadway, and 7 miles of stop and go traffic in the city.

I wondered if it were possible there was any carbon build up on the valves, since I had not done any 'open road' riding in nearly two months. I buttoned the bike back up and ran some Seafoam thru a tankfull of gas. I really didn't expect the Seafoam to change anything, but I figured I would give it a try anyway. I ran the bike on long non-stop stretches of roadway with speeds mostly from 60 to 80 MPH, and burned thru a full tank of gas (~300 miles)

I tore the bike down again last night in preparation to adjust the valves today. I had all the parts in hand and was fully ready to tackle the job.

I measured the valves first thing this morning, and all of the valves are now within specifications!

I don't know for sure what could have caused the change. The only differences were: Seafoam thru a tank full of gas, and the ambient temperature around 70? F.

I really don't think either of these (Seafoam or ambient temperature) could have made such a difference in the valves. I think Seafoam is a good product, but I wouldn't fully expect it to clean carbon from an engine in just 300 miles thru the gas. However, I will use it in at least one tankful before performing the next valve check at 32k.

Anybody else had an similar experience?

 

[wjbertrand]

I would have expected any carbon deposits on the valve to interfere with them closing fully, therefore increasing valve lash clearances to the high side. It follows then that anything that would remove that carbon (SeaFoam, Techron, etc.) should have resulted in better valve seating and tighter clearances - the opposite of your observations. Can anyone explain this or am I thinking backwards?

 

[Hotel 179]

I just performed the 16k valve check on my bike....twice.


Anybody else had an similar experience?

Sometimes you gotta beat that ST like a rented mule. Take it red-line every day, at least once.

 

[Mellow]

Is this the first one you've done? Any chance you just didn't do the procedure right the first time? I would think the measurements would be more dramatic if a step was missed or the engine wasn't turned exactly per procedures... You know what they say about measuring twice and cutting once...

 

[Blrfl]

It follows then that anything that would remove that carbon (SeaFoam, Techron, etc.) should have resulted in better valve seating and tighter clearances - the opposite of your observations. Can anyone explain this or am I thinking backwards?

Sounds kinda right to me.

--Mark

 

[okmurdog]

I would have expected any carbon deposits on the valve to interfere with them closing fully, therefore increasing valve lash clearances to the high side. It follows then that anything that would remove that carbon (SeaFoam, Techron, etc.) should have resulted in better valve seating and tighter clearances - the opposite of your observations. Can anyone explain this or am I thinking backwards?

I agree..carbon build up on the seat would make the valve clearance read larger.

 

[okmurdog]

Is this the first one you've done? Any chance you just didn't do the procedure right the first time? I would think the measurements would be more dramatic if a step was missed or the engine wasn't turned exactly per procedures... You know what they say about measuring twice and cutting once...

The short answer is no...I am confident the procedure was done correctly both times.

This is the first time I checked the valves on the ST; however, I have checked and adjusted valves in other motorcycles (as well as cars, trucks, and a tractor).

Bottom line...something caused those valves to shift. I am inclined to think the 'blowing out' riding had something to do with it.

I also wonder how much the ambient temperature affects (if any). The manual states the engine must be below 95? F...logic would dictate there would be a bottom end temperature spec as well, as metal shrinks the colder the temperature.

 

[Mellow]

I think I remember at the Witchita Falls Tech STOC they checked an 1100 after several hours of sitting then checked it the next morning and they were different so even though the bike seemed cold it wasn't stone cold so I would imagine the ambient temp has to affect it some.

 

[Hotel 179]

I know it's a different animal, but we'd adjust the valves on the Harley when it was stone cold.

 

[jvick98]

Mark,

I had same/similiar experience three weeks ago. Checked valves on ST1100 (the one Joe referred to at Wichita Falls) and several were at the loosest end of range. Buttoned it up, rode two tanks of Techron on trip to South Dakota and checked again. This time all had pulled back from the loose end and were now pretty well centered. No changes necessary.

Lesson learned: run Techron prior to next check.

Jim

Monument,Co

 

[okmurdog]

Mark,

I had same/similiar experience three weeks ago. Checked valves on ST1100 (the one Joe referred to at Wichita Falls) and several were at the loosest end of range. Buttoned it up, rode two tanks of Techron on trip to South Dakota and checked again. This time all had pulled back from the loose end and were now pretty well centered. No changes necessary.

Lesson learned: run Techron prior to next check.

Jim

Monument,Co

Thanks for the info Jim.

I remember at the TX TechSTOC there was an issue with one or two bikes that were checked preliminarily the night before and found out of tolerance. However, when the valves were checked the next day, all were good (the engines had not fully cooled off).

The lesson I learned from the TX TechSTOC is to make sure the bike is fully cooled off - this is why I pulled the plastic the night before when I checked mine.

Even though the Service Manual does not have a low end ambient temperature specification when checking the valves...in the future, I think I will check the valves in an ambient temperature range between 70? and 95? degrees Fahrenheit.

 

[BigBadblue]

Food for thought: I own a Nissan Armada which has a 32 valve DOHC V8 with shim under bucket (actually the bucket is the shim), just like the ST. The factory Nissan service manual states that no adjustments are required over the life of the vehicle, ever. I also own a 2001 Yamaha WR426 DOHC w/5 Ti valves. It has required 1 shim in 8 years and it was on the ragged edge of not needing it, I suspect it was that way from the factory. From what I have seen if any adjustments are needed, the clearance will be too tight from valve "tulip" and beat valve seats/stretched stems. the clearances should not loosen up, just get tighter.

 

[ST/SV]

I'm fixing to do a valve check tomorrow night, temperature should be in the 60's. So ya'll are saying that there could be a difference in clearances between a 40-50 degree engine and an engine that is in the 80-90 degree range.

 

[okmurdog]

I'm fixing to do a valve check tomorrow night, temperature should be in the 60's. So ya'll are saying that there could be a difference in clearances between a 40-50 degree engine and an engine that is in the 80-90 degree range.

Logically, it seems there would be a bottom end temperature spec. I am thinking the clearances would measure differently if the engine temperature is at 32? versus 95? Fahrenheit. The service manual only specifies the engine temperature be below 95? F.

I only say this because I can't explain why I obtained such a difference in the valve measurements.

I do know there was an engine temperature difference between the two measurements, and Sea Foam worked it's way thru the engine between measurements - which one of these variables (or both) affected the results....I don't know for sure.

I am very confident in my methodology of measuring the valve clearances, so I discount this portion of the process as a non-variable, given the amount of differences between the measurements.

I think the ambient temperature is something that needs to be taken into consideration...at least until the theory can be proved/dis-proved.

If I can motivate myself to pull the tupperware again (and miss riding a day) - I plan to check the valves again. My goal is to check the valves when the ambient temp is around 90? F and compare the results from the previous two results.

 

[Spencer]

You want to get really confused, stop by next time I do a Ducati valve
adjustment, and I'll let you use the harmonic hertz meter to adjust the
timing belts to a perfect "A" pitch :hyp1:

Fabio Taglioni is my hero :bow1:

.

 

[Byron]

I did my 80K not long ago and posted the information here. Take a look at the numbers. I don't know what your numbers were but I would bet that if they were within 0.001" it might have had to do with how the feeler was inserted. Anyone that has check the ST1300 valves know that the inside valves can be a pain to get the feeler gage in. Maybe the first time there was a little bit of an angle on the gage and it required a smaller feeler to get between the cam and bucket. The second time you checked you might have got a better angle and a larger gage happened to fit.

Just a thought!

 

[okmurdog]

I did my 80K not long ago and posted the information here. Take a look at the numbers. I don't know what your numbers were but I would bet that if they were within 0.001" it might have had to do with how the feeler was inserted. Anyone that has check the ST1300 valves know that the inside valves can be a pain to get the feeler gage in. Maybe the first time there was a little bit of an angle on the gage and it required a smaller feeler to get between the cam and bucket. The second time you checked you might have got a better angle and a larger gage happened to fit.

Just a thought!

I hear what you are saying....however; two of the three valves I found out of spec are the easiest to measure (#1 Front Intake, #2 Front Exhaust).

Plus, I measured using two different sets of feeler gauges - and the Metric is graduated in finer increments than the English.

English increments at 0.001" (equivalent to 0.0254 mm increments)
Metric increments at 0.01 mm increments (~ equivalent to 0.000394" increments)

As you can see, using a feeler gauge incremented in 0.01 mm gives you much better resolution on the readings.

Both sets of feeler gauges measured the valves out of spec

 

[BigBadblue]

I have been a prototype machinist/designer for over two decades and deal with tight tolerances everyday and 0.001 inches variance in valve lash is relatively nothing. Consider a regular sheet of printer paper (thin, cheap stuff) is between 0.003 and 0.004 inches. As long as the clearances don't get too tight which I think would usually only happen under severe abuse, i.e. many long hard runs at hi rpms, there should be no reliability issues, at worst a minute power loss. If they are loose I would suspect an oiling (flow) problem (cam, bucket wear). Overall the shim/bucket design is very robust, despite the hassle of shim replacement is pretty much bulletproof. The cam lobe/bucket interface runs submerged in a pool of oil (very little wear), unlike the rocker arm type design. The bucket design also produces zero side load on valve stem (vs rocker arms). I would bet after the valve train has gone through its initial bed-in(break-in) there will be nearly no change in lash if measured properly for many years.

 

[wjbertrand]

Nice Avatar BigBadBlue! I used to have an '83 Interceptor exactly like that, still kinda miss it.

 

[BigBadblue]

Nice Avatar BigBadBlue! I used to have an '83 Interceptor exactly like that, still kinda miss it.

I miss mine too. I bought it early in 83 (original owner) and it was my sweet heart for 22 years and I sold it to my best friend in 2005 (that was when the pic was taken), now some big time lawyer has it in his private collection/museum (~76 bikes). Once I installed the Hot Cams and oiling kit the cam wear problems ended. I should have sold some other toys and kept it.