How-To: Valve Adjustment for Honda PCX

[Cascanciu]

It's so good to have this how-to. It'll be useful once my warranty is over.
I talked about it with my dealer's workshop supervisor, and he told me that the valve adjustment schedule was quite exaggerated, in their opinion, and that they would carry it out if, on hearing the engine, they considered it necessary. This makes me think that Maddiedog is right. You hear clicking, go ahead, otherwise it's quite likely that everything is within specs.

[you you]

It's so good to have this how-to. It'll be useful once my warranty is over.
I talked about it with my dealer's workshop supervisor, and he told me that the valve adjustment schedule was quite exaggerated, in their opinion, and that they would carry it out if, on hearing the engine, they considered it necessary. This makes me think that Maddiedog is right. You hear clicking, go ahead, otherwise it's quite likely that everything is within specs.

I agree - use a bit of common sense is best. Sometimes its best to leave things alone and worry about something else.

If the tappets become noisy then the valve clearance is probably increasing due to general wear, but if there is no change in the sound the clearance could possibly be decreasing. Less likely but the valve seats could be sinking etc. and you'd probably notice a drop in performance. Not very likely at all really.


So if its running right and sounding right - leave it be?

[Cascanciu]

I, personally, will ask the mechanic to do the valve adjustment at the 4000 kms service, just as a precaution. Sometimes, vehicles come out of the production line with slight flaws. I have noticed this myself in my brother's VW. Golf. I noticed something weird on the steering and realized it was a wheel alignment thing. The dealer took care.

After the first adjustment, I'll probably do them every 5000-7000 kms or when they click.

[maddiedog]

So if its running right and sounding right - leave it be?

That's what I stick to with my PCX and all my other vehicles, and haven't had a problem yet.

If the tappets become noisy then the valve clearance is probably increasing due to general wear, but if there is no change in the sound the clearance could possibly be decreasing. Less likely but the valve seats could be sinking etc. and you'd probably notice a drop in performance. Not very likely at all really.

I've never heard of valve clearance decreasing, usually when clearances are too tight, they were just improperly adjusted initially. If you think about it, those valves won't tighten themselves.

[you you]

I've never heard of valve clearance decreasing, usually when clearances are too tight, they were just improperly adjusted initially. If you think about it, those valves won't tighten themselves.

It can happen but it's rare and due to wear, as is increasing clearance. Just mentioned it as someone will pick it up and run with it if I didn't.

It's worse really as there are real signs of it other than a loss of power and eventually you can burn a valve out

But as you rightly say its an irrelevance really on the PCX running on proper fuel

[suitcasejefferson]

Hello, My name is Jim, I'm new here and a new PCX150 owner. I almost didn't buy it when I found out how complicated the valve adjustment was (my Vino 125 takes about 15 min, very little plastic to remove). It still has less than 100 miles on it, I plan to adjust the valves at 1000 miles, then at 5000 miles, then see how things go. My Vino 125 says to check the adjustment every 3000 miles, but I have over 15,000 miles on it, and have adjusted them once.

I have a question about the sealant. Is this something you can buy at Honda? If not, does anyone have a brand name or part number for it?

Also, just an observation. I have been riding motorcycles and scooters for 45 years, and have had 41 of them. I currently have 7, counting this new PCX150. I have always adjusted the valves to the loose end of spec, and have without fail found that as the valves wear, they tighten up. The cams, rockers, and adjusters do not wear, there is no metal to metal contact between them. What wears is the valve and valve seat inside the combustion chamber. As the valve and seat wears, the valve gets recessed farther and farther up into the seat, allowing the end of the valve stem to get pushed farther out, which decreases the clearance. I have always done all my own work on my bikes, and never seen valve clearances get looser. If they did get looser, the valves would not open all the way, and you would notice a severe decrease in performance before any damage was done. But when they get tighter, the valves do not close all the way, not only causing a major loss in performance, but since the edges of the valves do not contact the seat, they cannot transfer heat to the seat, resulting in burned valves. Wondering if anyone else has any experience or opinions on this. Thanks. Jim.

[you you]

Its a mix of loosening/tightening for me but in general its check and leave alone if in tolerance. If it sounds right, runs right and hasn't done a whopper mileage I generally leave it.

Had a period of tightening valve clearance in my Mini Cooper when unleaded fuel came out due to seat wear. Just kept an eye on it and eventually changed the seats/valves

My oilhead boxer cup on the other hand had a period of loosening up until it stabilised. This is the only bike I fiddle with really as I like to keep the gaps the same on both sides.

[maddiedog]

Hello, My name is Jim, I'm new here and a new PCX150 owner. I almost didn't buy it when I found out how complicated the valve adjustment was (my Vino 125 takes about 15 min, very little plastic to remove). It still has less than 100 miles on it, I plan to adjust the valves at 1000 miles, then at 5000 miles, then see how things go. My Vino 125 says to check the adjustment every 3000 miles, but I have over 15,000 miles on it, and have adjusted them once.

I have a question about the sealant. Is this something you can buy at Honda? If not, does anyone have a brand name or part number for it?

Also, just an observation. I have been riding motorcycles and scooters for 45 years, and have had 41 of them. I currently have 7, counting this new PCX150. I have always adjusted the valves to the loose end of spec, and have without fail found that as the valves wear, they tighten up. The cams, rockers, and adjusters do not wear, there is no metal to metal contact between them. What wears is the valve and valve seat inside the combustion chamber. As the valve and seat wears, the valve gets recessed farther and farther up into the seat, allowing the end of the valve stem to get pushed farther out, which decreases the clearance. I have always done all my own work on my bikes, and never seen valve clearances get looser. If they did get looser, the valves would not open all the way, and you would notice a severe decrease in performance before any damage was done. But when they get tighter, the valves do not close all the way, not only causing a major loss in performance, but since the edges of the valves do not contact the seat, they cannot transfer heat to the seat, resulting in burned valves. Wondering if anyone else has any experience or opinions on this. Thanks. Jim.

Welcome, Jim!

You should use HondaBond HT. I've had good luck ordering from these folks in the past, but your Honda dealer should also be able to get it for you: http://www.rockymountainatvmc.com/p/43/ ... HT-3.5-oz.

[sendler2112]

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.

Yes except that valves always wear tighter, not looser. If you neglect the valve adjustment long enough, the valves can get so tight that the bike will start running bad and could burn a valve.

[maddiedog]

Hmm... Hondas have a rocker between the cam and the valve. Wouldn't the rocker wear down too, loosening the valve? There's more to wear in the valvetrain than just the valves and lashes.

Saying valves always wear tighter is silly. My CR-V's valves were always on the loose end of the spectrum. I think it's a YMMV thing.

[SUNNY SIDE GA]

Thinking about getting the 150, is valve adjustment every 4000 miles on it also? With ALL the crap you have to dismantle to do this I think IF I purchase this bike I'll let the dealer do such, without guesses. What does a U.S. dealer charge for such?

[EddieC]

Dealers in CA charge between $300 and $400 for a service. You could probably save a lot of coin by removing the plastics yourself and having the dealer do the adjustment only, but honestly removing the plastics is the hardest part. To do this yourself will only cost you $2 for some gasket sealant. If you're in GA maybe maddiedog would help walk you through it the first time.

[EddieC]

And yes the valve adjustment is every 2500 miles for both the 125 and 150, but you will probably be fine doing it every 4000 miles after your initial adjustment

[SUNNY SIDE GA]

Thanks for the additional info, the amount I would save in gas with the 150 would be probably be consumed with a dealer valve adjustment vs. a bike that got 45/50 miles per gallon that has NON adjustable valves. Just thinking ahead.

[maddiedog]

The valve adjustment isn't really bad at all. Honestly, you could take the Yamaha Vino / Honda Silverwing / etc approach and ignore the valves completely unless they become a problem. After reading up on Silverwings a lot (just bought one), most people don't touch the valves after the first adjustment. People have checked 100k+ miles later and been fine.

I'm not saying you SHOULD neglect to check your valves after the first service, I'm just saying you COULD and it would probably be fine.

[loudgonzo]

i just tried this and i think i messed it up. The intake was about .13 and the exhaust was good. I adjusted and closed it to .10 on feeler gauge, tightened up, and put it back together. Started fine, but after about a minute it started to knock.

Since it took me while to take it apart, and put it back together, (have the givi e370 box installed), i decided to just drive it to the dealer and just let them do it. It was too hot in garage and i would have probably done something worse trying to take it apart again.

If i try again, i will make sure to start and test BEFORE putting all sides and panels back on. Dealer is overloaded with work, so it'll be about 2 weeks.

[EddieC]

Man that sucks. If its going to take that long why not grab it from the dealer and open it up again in the morning when it's nice and cool? If you have all the plastics off and double check your work and it still knocks, you could bring it back to the dealer without the plastics on and that would also save you a bunch of labor at the dealer. It may even get you outta there faster. Just the fact that you were able to ride it holds well. Did you notice a decrease in power?

[loudgonzo]

no loss in power. dealer about 12 miles away, and even drove it wot for a little bit, doing around 65mph. the knocking is heard when stopped, can't hear or notice anything else while driving.

i think it'l be best just leave it there, get it done, and take it even slower next time i dig into it, maybe i didn't tighten the nut all the way down, or something else that i just simply didn't catch.

i did start in the morning by the way, i'm in texas so its already 85 in the morning!

[jasontheparamedic]

Where can I find a feeler gauge? The do-it-yourself valve adjustment would save me a ton of money and make owning this bike extremely money efficient, despite the risks.

[gn2]

Feeler guages are standard tools, you should find them in any decent tool shop.