The Honda PCX / Forza / ADV150 / SH Forums

Valve Adjustment How-To

Alright guys... here we go... Disclaimer first!

Disclaimer:
I am not at all a professional mechanic... I have taught myself about engines on a couple other bikes I have had. A "71 CB500, then a "01 SV650 with large help to the internet and friends. I will do my best to describe a valve adjustment but will not be held responsible if anything goes haywire with your bike after doing your own maintenance. This is not professional advice. Please correct me if I mixed something up or used incorrect terms and I will edit to perfection. Thanks!

SOURCES: (pictures and quotes)
Honda Motor Co., Ltd. Honda Service Manual 2011 PCX125. N.p.: Service
Publication Office, 2010. Print.

Tools needed. Plastic removing tools, feeler gauges, 8,9,10,12,22mm open end wrenches, 8,10,12mm sockets with extension, phillips head screwdriver, gasket sealant.

maddiedog wrote:Your bike must be cold when doing a valve adjustment. You should wait at least 4 or 5 hours since it has been on last. If you do not, you may burn yourself or set clearances too tight, since the metal expands slightly when hot.

Some people even like to wait overnight (like me)

Remove the plastics. I started with the lower: remove BOTH sides


dont forget!


then the seat:


then the center cover:


then the grab rail cover:


then the grab rail:


then the side covers: (no need to remove the taillight, will all come off in one piece


then the cargo box:


Then remove the battery box. (1 bolt). DO NOT disconnect the battery yet, you will need it in a moment. when you're done it will look something like this.


Disconnect the fuel pump:


then relieve the fuel pressure. turn ignition on and press the starter for 5 seconds. After that, remove the fuel line, fuel line clamp bolt, and the crankcase breather hose




pull up on the green tab to remove: use a rag to catch excess fuel


Then remove the cylinder head itself, Exposing the valves. 3 bolts




then remove 3 bolts on the left cover exposing the crankshaft


Remove the right side radiator cover (3 bolts) and remove the 4 bolts holding the radiator on to expose the fan. Do not disconnect any hoses going to the radiator.


turn the crankshaft COUNTER CLOCKWISE until the index mark and the cutout on the fan line up as pictured above, test to see if there is slack on the rocker arm by giving it a wiggle


if it feels like its not moving then you will need to spin the crankshaft a full 360 degrees to be at top dead center. Verify that the index mark and cutout on the fan line up again, and verify that the index line and the punch mark on the camshaft line up pictured below:


once the piston is in the correct place, use your feeler gauges to measure the clearance between the valve adjusting screw and valve stem. The valve on the top of the engine is intake, and the valve on the bottom is exhaust. the clearance is

PCX 125/150:
INTAKE: 0.10 +/- .02mm (0.004 +/- 0.001in)
EXHAUST: 0.24 +/- .02mm (0.009 +/- 0.001in)

If the valve clearance is incorrect, loosen the valve adjusting screw lock nut and adjust the valve clearance by turning the adjusting screw until there is a slight drag on the feeler gauge.

I found it easiest to loosen the nut a lot and just twisted the adjusting screw by hand, gave me better control than pliers.

once you're done reassemble in the reverse order.

be sure to re-apply sealant on the cylinder head cover to the places shown here:


Hope this helps!

Awesome, thanks for posting this up. Since the valves need checked every 4000 miles according to the manual, doing this yourself saves a lot of money.

Bit confused about the "gasket sealant"...?
What type of sealant to use, exactly where to put it and isn't there a gasket on the valve cover anyway...?

I use liquid gasket/sealer that you can get from Halfords for about a fiver (check it's use by date). You don't need to use much. There is a rubber gasket on the cover, I think the sealer is a bit belt and braces. When you remove the cover and gasket you will be able to see where to put the sealer by where the old stuff is stuck to the gasket. If you've got a spare Stanley knife blade lying about use it to scrape the old seal off. It all makes sense when you take the valve cover off.

Cheers edscoot, hopefully I'll suss it out as you suggest.

How long does it take to do this, once experienced? My bike is going in for its first service shortly and I wonder whether to ask them to adjust? I am definately asking them to adjust my combo brake lever which is too loose. Also I plan to ask if they can do a rear shock upgrade.

Honda will usually charge you for more labor than what it actually takes, just FYI

Now that i know what I'm doing, I can do a full valve adjustment in about an hour and a half. The first time around easily took me twice as long but that's okay because i was being extremely careful learning how to remove the plastics the first time. Also, the combo brake lever is an easy fix, if you're planning on doing any of this yourself.

Hello there... Nice job with the pictures.
Can i ask if is possible for a copy of this manual???

Hello. I don't have a scanner but if you need help with anything here just ask and I can provide pictures. I'm sure a bunch of other people would be kind enought to chime in and hey, we all like to help

stavkostakis wrote:Hello there... Nice job with the pictures.
Can i ask if is possible for a copy of this manual???

Unfortunately, the manual is copyrighted. You can easily buy one from Helm Inc, they are the publishers of the manual. Occasionally, they pop up on eBay... Also, there is no (legal or otherwise) digital copy of the manual.

Specific pages can be posted as reference under fair use (like the pages above), but posting or sharing of the entire manual would be illegal.

did a valve adjustment to a friends brand new PCX. He held off on doing the first valve adjustment until 1200 miles. Both the intake and exhaust valves were tight and needed adjustment. I just hit 8500 miles myself. I'll prob be doing another valve check on the PCX this sunday and will report back if I need to adjust them.

Also, told my friend about this site, but I guess he's not one for forums. =]

Both the intake and exhaust valves were tight and needed adjustment

How far out of spec were they Eddie? It would be nice to know when people inspect their valves and what they find at different mileages. We haven't done ours yet, but our intention is to check them less frequently if we think we can get away with it. So far I don't think I've heard of anyone's being that far out of spec so I'm sticking with that plan.

The intake was about 0.002 inches tight as I could barely squeeze the correct feeler gauge in the gap and the exhaust was about 0.003 inches tight seeing that I could not get the correct feeler gauge in the gap.

When I did mine the valves were within spec but a little tight at 600 but needed to be adjusted at 2500 miles. At 6000 they were within spec. I was planning on doing my next adjustment around 9000 miles but will do it a little early just because I have some free time. Then probably not until I have 12,500 miles.

I think doing a valve check is very important for the 600 mile and 2500 mile checks, but after that you could probably get away with doing them every 4000 miles.

How many miles are on your scoot now rainburg? You haven't done a check at all?

Oh no, I guess I'll have to confess that I only have about 650 miles on my PCX. We bought it in September at the start of the rainy season, and it sat in the garage for much of the cold, rainy winter. I took it out every week or two for an errand run, but that was about it for much of winter. We've done the first oil change already, but we were planning to wait until around 1,000-1,200 miles for the valve check. Then perhaps every 4,000 miles if we think that it isn't too risky.

That oil change is definitely the most important thing to do at 600 miles, so good job there. I take it you cleaned the oil filter too? I think you would be fine holding off on the initial valve adjustment but try to get it done more around 1000 miles. My friends was OUT of spec (no good) at 1200 miles. If he went much longer he could have possibly done some damage to the engine. After your first check, I would still do the second after an additional 2500 miles. For the third fourth and so on I think you would be fine checking every 4000 miles.

There is actually a third PCX that I have done valve checks on. On that third PCX we never needed to make an adjustment at the 600, 2500, and 5,000 mile points. The owner sticks to his maintenance schedule and so far has never needed to touch the valve adjusters. But the only way you can know for sure is to open it up and take a look. it's sad but true. Once you have done it once it's super easy the next time around, and doesn't cost you a dime if you plan on doing it yourself.

Thanks Eddie for all the information! We did clean the oil filter, although there really wasn't anything noticeable on it. It all looked very clean.

Just out of curiosity, has anyone else found that the valves were out of spec? If so, at what mileage and when had the previous check/adjustment been done?

Mine were out straight from the factory, at first service. They've been behaving since, though.

The tolerances for the valves on the PCX are HUGE, so you don't have much to worry about unless you hear clicking.

Anyone know how to get a service manual that has these procedures?

Helm is the publisher for the official Honda Service Manual, I think. You can buy it here: http://www.helminc.com/helm/product2.as ... itemtype=N

Small snippets like these are considered "fair use." If you want any sections uploaded to help you with miscellaneous tasks, you can ask and someone will upload a picture or two from their manual. I have a manual, Eddie has a manual, and I think a few others have access to one as well.

Just did another valve check this morning. I waited about 4300 miles since my last one. Everything was exactly in spec and didn't need to be adjusted at all!. I think people will be fine doing the valve adjustment every 5000 miles. However, I would still be sure to do the first two on schedule (600 mile and 2500 mile) while breaking in the engine seeing that thats when both my friend and myself needed adjustments.