PCX Valve Adjustment

proxes27 · Post by **proxes27** » Thu Oct 18, 2012 10:18 pm

When has everyone been getting their valves adjusted?

gn2 · Post by **gn2** » Thu Oct 18, 2012 10:32 pm

From new till 10,000 miles mine was dealer serviced.
No idea whether the dealer actually did adjust them.
The scooter now has 12,500 miles on and I may take a look at the valve clearances at 15,000 miles when its due for a new drive belt and oil change.

Teamtd11 · Post by **Teamtd11** » Fri Oct 19, 2012 7:50 am

I checked mine at 5000 miles. Had it dealer serviced at 600 and 2500 miles.
I don't think I will check them now until 15000 miles as they were on the tighter side of the tolerances when I checked.

Spleege · Post by **Spleege** » Mon Oct 22, 2012 3:08 pm

I have 1200 miles on my PcX 150 and have not yet brought it in for first service. I dont hear any valve noise and have not had any performance issues. should i wait longer maybe to 1500 or 2000 miles? what is your guys opinions?

you you · Post by **you you** » Mon Oct 22, 2012 3:21 pm

Spleege wrote:I have 1200 miles on my PcX 150 and have not yet brought it in for first service. I dont hear any valve noise and have not had any performance issues. should i wait longer maybe to 1500 or 2000 miles? what is your guys opinions?

Have you changed the oil in it

Alibally · Post by **Alibally** » Mon Oct 22, 2012 3:24 pm

qed wrote:
Spleege wrote:I have 1200 miles on my PcX 150 and have not yet brought it in for first service. I dont hear any valve noise and have not had any performance issues. should i wait longer maybe to 1500 or 2000 miles? what is your guys opinions?

Have you changed the oil in it

Ditto. It's important to change the oil and clean out the screen filter way before 1200 miles. Should be done at half that.

Spleege · Post by **Spleege** » Sat Oct 27, 2012 2:57 am

considering this is a liquid cooled motor with a rev limiter I just wasn't worried. I didn't waste the money bringing it to a dealer to have a service done, have them break all the plastic tabs and not tell me. I bought the service manual. After about 2 hours of removing plastic i finally got to the head, popped it off and as i suspected the valves were exactly at factory settings. .004 intake and .009 at exhaust. additionally the oil was pristine and a light brown. anyone getting paranoid about late services, forget about it. this motor is rock solid. I'm 230, 6'3" and this thing cooks along on flat ground at the rev limit of about 65. great bike. I could not believe all the evap lines and smog crap on this bike. well i do live in california, unfortunately.

Pcxdemon · Post by **Pcxdemon** » Sat Oct 27, 2012 4:30 am

Spleege wrote:considering this is a liquid cooled motor with a rev limiter I just wasn't worried. I didn't waste the money bringing it to a dealer to have a service done, have them break all the plastic tabs and not tell me. I bought the service manual. After about 2 hours of removing plastic i finally got to the head, popped it off and as i suspected the valves were exactly at factory settings. .004 intake and .009 at exhaust. additionally the oil was pristine and a light brown. anyone getting paranoid about late services, forget about it. this motor is rock solid. I'm 230, 6'3" and this thing cooks along on flat ground at the rev limit of about 65. great bike. I could not believe all the evap lines and smog crap on this bike. well i do live in california, unfortunately.

I saw and rode a Pcx 125 last night that had done 28000km and no valve adjustments in the last 24000km,oil servicing every 5000km. It ran and felt like brand new still...

rainburg · Post by **rainburg** » Sun Oct 28, 2012 12:00 pm

We are just putting our PCX back together after doing our first valve check at about 1200+ miles. It was out of spec on the intake at .006 and the exhaust was good at .009 so we only had to tighten the intake. I'm glad that we finally checked as I wouldn't want to be running it much out of spec, but I suspect that the schedule listed in the manual has an abundance of caution and I'm comfortable stretching the guidelines some.

Many thanks to Eddie for the tutorial and advice. We have the service manual, but it was nice to have a second resource to double check a few times.

EddieC · Post by **EddieC** » Sun Oct 28, 2012 12:36 pm

You're very welcome! Glad it has been a good tool for people to use.

ericpcx · Post by **ericpcx** » Fri Nov 16, 2012 3:58 pm

I agree

Spleege wrote:considering this is a liquid cooled motor with a rev limiter I just wasn't worried. I didn't waste the money bringing it to a dealer to have a service done, have them break all the plastic tabs and not tell me. I bought the service manual. After about 2 hours of removing plastic i finally got to the head, popped it off and as i suspected the valves were exactly at factory settings. .004 intake and .009 at exhaust. additionally the oil was pristine and a light brown. anyone getting paranoid about late services, forget about it. this motor is rock solid. I'm 230, 6'3" and this thing cooks along on flat ground at the rev limit of about 65. great bike. I could not believe all the evap lines and smog crap on this bike. well i do live in california, unfortunately.

OriginalRocket · Post by **OriginalRocket** » Sat Jul 13, 2013 9:18 am

7250 miles, and my third valve check. They are exactly where I placed them at my second valve check at 3500 miles. Both valves were tight on the 600 and 3500 mile check. Now they haven't moved in 4000 miles.

My next vavle check will be 15000 miles, when I replace the belt.

Question for everyone. Does the PCX valves tend to get tight, or open the gap as the valves wear and fall out of spec.?

maddiedog · Post by **maddiedog** » Tue Jul 16, 2013 9:37 am

There's no good answer... Most people say valves get tighter as they wear, I've experienced the opposite. YMMV.

WI_Hedgehog · Post by **WI_Hedgehog** » Fri Jun 29, 2018 8:19 am

There's a lot of threads where members try to convince each other the valves don't need adjustment. They do, here's why:

Honda builds reliable, efficient, quiet engines. To get the most from them they need to be within specifications, and Honda clearly lays out what needs to be adjusted and when. With Honda, running an engine "a little out of spec" makes them run like most other engines, darn fine. HOWEVER, putting them dead-center of spec. or "a little toward the logical side" makes them run "perfect," meaning way better than other engines (and they tend to remain running that way pretty much forever...).

With valves, running them toward the loose side of center of spec. is better. Today's valves tend to not wear much as long as the oil is changed regularly, so they tend not to loosen up over time from wear. Carbon buildup is usually the dominating factor, actually tightening (reducing) the valve clearance, so running looser makes sense (vs tighter). Also, a valve running way too tight (meaning having little to no valve lash causing the valve to open early) can burn the valve and seat, whereas running loose (lots of lash causing the valve to be open a shorter duration) will result in a slight loss of power and some chatter (the saying used to be "tappy tappets are happy tappets)--although slapping the cam and valve stem (which makes that tapping sound) isn't good, it's better to get some audible warning to adjust the valves (tapping from too much lash) than melt down the engine from too little valve lash. Note I'm saying keep the valve lash within specifications, and instead of "exactly between the minimum and maximum specs." perhaps adjust between center and the maximim spec.

So to use simple numbers,
if the lash spec was between 0.001 and 0.010 (which it's not, and the intake and exhaust valves each have different specs.)

"tight" or "opening early" would be 0.001
"loose" or "short duration" would be 0.010
the midpoint would be 0.005
and I would set the lash between 0.007 and 0.008.

I would expect the lash to decrease over time to 0.005, at which point I would adjust it back to 0.007.

If the lash loosened up over time (instead of tightening) this would probably be due to wear (if it is not a loose valve stem nut) and I'd be sending the oil in for testing to see what is wearing and putting metal particulates in the oil, because there's probably some sort of engine casting chip that broke off and is blocking an oil passage.

Again, that's an example and not the actual values.

you you · Post by **you you** » Fri Jun 29, 2018 1:12 pm

Oh God not again.

PCX150Rider · Post by **PCX150Rider** » Fri Jun 29, 2018 4:02 pm

I've got somewhere around 2500 miles on my 2017 and haven't adjusted my valves yet. They have a little bit of noise as they did new. A noisy valve means the valves are closing because there is clearance. Too much clearance (can sound louder or more metal on metal) effects performance by not allowing the valves to open enough thus starving the engine for fuel/air or to allow exhaust to vent in a timely fashion.

If they start to get quieter or something gets out of character I'll pull the panels and check them. I think the U.K. manual calls for valve maintenance every 4K miles if I'm not mistaken. My U.S. manual indicates every 2500 or something. Go figure. . .. The performance is consistent so far. I check my oil and coolant levels and don't run the Bejeezus out of it.

you you · Post by **you you** » Fri Jun 29, 2018 5:07 pm

PCX150Rider wrote:I've got somewhere around 2500 miles on my 2017 and haven't adjusted my valves yet. They have a little bit of noise as they did new. A noisy valve means the valves are closing because there is clearance. Too much clearance (can sound louder or more metal on metal) effects performance by not allowing the valves to open enough thus starving the engine for fuel/air or to allow exhaust to vent in a timely fashion.

If they start to get quieter or something gets out of character I'll pull the panels and check them. I think the U.K. manual calls for valve maintenance every 4K miles if I'm not mistaken. My U.S. manual indicates every 2500 or something. Go figure. . .. The performance is consistent so far. I check my oil and coolant levels and don't run the Bejeezus out of it.

Incredibly sensible post and I agree. But we are responding to a bit of Hedgehog willy waving. He knows science

WI_Hedgehog · Post by **WI_Hedgehog** » Thu Jul 05, 2018 9:12 pm

I kind of know engines too, because I actually work on them myself...

I also have panel removal tools, spare clips (for cars/trucks), etc., so am a bit prepared to pull panels on the PCX.

Davepcx · Post by **Davepcx** » Fri Jul 06, 2018 6:28 am

Just checked mine yesterday.
Considering how many people say its a lot of work i found it fairly easy. Takes at least twice as long to do on my quad.

Anyway my intake was 0.9 and exhaust 0.24 mm pretty much bang on spec although I did adjust the intake back to 0.10mm . 970 miles on my scoot and did my second oil change at the same time...
Easy job to do , no broken plastics or clips . Took about 1.5 hours start to finish...

springer1 · Post by **springer1** » Fri Jul 06, 2018 7:02 am

Davepcx wrote:Just checked mine yesterday.
Considering how many people say its a lot of work i found it fairly easy. Takes at least twice as long to do on my quad.

Anyway my intake was 0.9 and exhaust 0.24 mm pretty much bang on spec although I did adjust the intake back to 0.10mm . 970 miles on my scoot and did my second oil change at the same time...
Easy job to do , no broken plastics or clips . Took about 1.5 hours start to finish...

My experience as well, but I’m a little slower. Homie’s videos are super valuable.

The Honda PCX / Forza / ADV150 / SH Forums