The Honda PCX / Forza / ADV150 / SH Forums

PCX150Rider wrote:Sorry to hear about that.

I was going to mention some things to check but don't want to insult your intelligence.

The nut is still somewhere in the engine if you lost it and haven't recovered it so far.

GGGeeeezzzzzzzzzzz....that's a real bummer.

If it was me I'd have to take the engine apart and reassemble it to an extent required to find that nut and make sure next time I didn't leave it loose. But that's me. It's only a single cylinder fortunately. Otherwise it would be a mega $$ money job at a dealer mechanic.

Here is a link to a fast forward Kymco Agility 125 motor build video. It will help calm some of the fear of unknown. It's a different engine type and fueled by a carburetor but will give you something to think about. . . as well as your finances and tool inventory. https://www.youtube.com/watch?v=-cpB83KXfgE

Again, sorry to read about your dilemma.

The nut was tightened to spec, thanks for the condescending remarks though!

RuckinEMT... did you take to 7 in. lbs or 7 ft. lbs

I know we are little help to find it, and I feel the pain for something that Honda claims needs doing that most likely doesn't. The ability to apply a torque wrench to this lock nut is tricky. Even the SM shows a 9m box end wrench on the lock nut. So how did you achieve the 7 ft lbs to this lock nut given the special tool it would take? Was it something like this...

Chief is dying right now looking at my tools, but how did you get this done?

homie wrote:

tool.jpg

I know we are little help to find it, and I feel the pain for something that Honda claims needs doing that most likely doesn't. The ability to apply a torque wrench to this lock nut is tricky. Even the SM shows a 9m box end wrench on the lock nut. So how did you achieve the 7 ft lbs to this lock nut given the special tool it would take? Was it something like this...

Chief is dying right now looking at my tools, but how did you get this done?

I used this...
https://www.amazon.com/Bicycle-Torque-W ... que+wrench

RuckinEMT wrote:I used this...
https://www.amazon.com/Bicycle-Torque-W ... que+wrench

That's in Newtom Meters only, so as not to insult your itellgence you do know you needed 10 Nm to get 7 ft lbs right?
10Nm= 7.375621ft-lb
And to be clear you had to rig something up like I show to get the torque wrench to work on a box end wrench... correct?

Yes, I did know that. Also, No I used a 9MM socket on it...

RuckinEMT wrote:Yes, I did know that. Also, No I used a 9MM socket on it...

That is incorrect, you must hold the stem with a small wrench like in the picture to the adjusted specs you found with the feeler gauge while you tighten the nut to 7 ft lbs. Here is where things went bad for your engine. I have no understanding of what this did to the valves at this point but I suspect you need to take it in. And thank you for admitting the details. It takes a big man to follow up with a post like this. It can scare the crap out of folks doing this work and we must have conclusion.
THANK YOU! Please confess this to the gorillas so they understand too.

the gorillas?

RuckinEMT wrote:the gorillas?

The ones who don't put all the nuts and bolts back properly The dealership

Start this 1:18 and see how this operation is performed.
https://www.youtube.com/watch?annotatio ... 0K-ytyjOFg

homie wrote:

RuckinEMT wrote:the gorillas?

The ones who don't put all the nuts and bolts back properly The dealership

Start this 1:18 and see how this operation is performed.
https://www.youtube.com/watch?annotatio ... 0K-ytyjOFg

That reference must be over my head. Again, thanks for the help...

RuckinEMT wrote:

homie wrote:

RuckinEMT wrote:the gorillas?

The ones who don't put all the nuts and bolts back properly The dealership

Start this 1:18 and see how this operation is performed.
https://www.youtube.com/watch?annotatio ... 0K-ytyjOFg

That reference must be over my head. Again, thanks for the help...

Might not turn out too bad, I'm thinking the stem moved with the lock nut when you use a socket over the whole thing. It seems to me you would have lost whatever adjustment you made immediately and set your valve or valves way too tight. Probably screwed down as far as they could go and then torqued. Absolute ZERO gap then started the engine. Something had to give when the piston hit the valves... thus the little nut or nut's stripped off instantly. I take it you didn't go far?

I sincerely hope a whisperer will awaken and debunk that diagnosis. I hate it as much as you do. Maybe it just was not tight a spun off. I dare not ask what you felt and heard on that short ride as you accelerated as this would finish the story I don't want to hear

homie wrote: Might not turn out too bad, I'm thinking the stem moved with the lock nut when you use a socket over the whole thing. It seems to me you would have lost whatever adjustment you made immediately and set your valve or valves way too tight. Probably screwed down as far as they could go and then torqued. Absolute ZERO gap then started the engine. Something had to give when the piston hit the valves... thus the little nut or nut's stripped off instantly. I take it you didn't go far?

The clearance will almost certainly have changed if you didn't hold the stem whilst tightening/torquing. Nothing else to do but check the clearance again as the not ticking over is a symptom of out of whack tappet clearances.

It's always best to recheck them after you've set them as they can drift during the tightening process even when you hold the stem.

Let us know how it goes.

I'm not a professional, so what I'm adding may not be absolutely correct, however..... I'm a new guy just trying to help but not make trouble .....

The ability to apply a torque wrench to this lock nut is tricky. Even the SM shows a 9m box end wrench on the lock nut. So how did you achieve the 7 ft lbs to this lock nut given the special tool it would take? Was it something like this...

..... am I correct that the torque wrench needs to be at a right-angle to the box wrench in order to get a correct reading? I'm almost certain that 'back when" we were re-torquing Norton heads and their mix of both head nuts and bolts (some of which being recessed in the side of the cylinder) we had to do this. I THINK we had to keep it at an angle to get it correct.

Also, note that those instructions from Honda mention a critical step - to oil the threads, so the measured torque is from a lubed surface, not a dry one.

Honestly, I've never used a torque wrench to adjust valves anyway, I probably erred on the heavy side, never had any work loose. On some engines, gaps would get tighter when then nuts were tightened even though the screw DIDN'T turn any. So, we'd back the screw out 1/8 turn after getting a good gap. Then mysteriously after tightened them up with the screw held firm, the gap would then be spot on .... go figure.

The nut was tightened to spec, thanks for the condescending remarks though!

Didn't mean to be condescending. . .however I am self critical when "I" foul up. . .and find much delight after further examination in cases where I discover whatever went wrong wasn't actually my fault at all to begin with.

Stuff loosens up on machines sometimes. . .I could produce a list. . .scary thought.

Something else I forgot to mention was that the use of "magnets" is sometimes productive in fishing for stray fasteners.

Homie brought up some good points. Recently I discovered I've got to get an additional torque wrench that will handle lower level torque specs in ft. lbs. The one I have now starts at 20 ft. lbs.. Somehow over the years I've been lucky tightening hold-downs and fasteners based on "feel". Also the kind of metal you are dealing with makes a difference. . .it almost becomes an art.

springer1 wrote:Honestly, I've never used a torque wrench to adjust valves anyway, I probably erred on the heavy side, never had any work loose. On some engines, gaps would get tighter when then nuts were tightened even though the screw DIDN'T turn any. So, we'd back the screw out 1/8 turn after getting a good gap. Then mysteriously after tightened them up with the screw held firm, the gap would then be spot on .... go figure.

Same here. I also leave the feeler gauge in place too. Not sure if it really helps but it doesn't seem to hinder.

This could happen to any of us and again I want to thank the OP for toughing this out to the best understanding for all of us. I know it won't fix the problem for our fallen brother but I pray it wasn't MY valve clearance video he was watching when he set out to do this without a service manual. Youtube is wonderful to move you along faster in motion picture but takes for granted you have some basic understandings of the more critical services. Annotations on YT videos can't be seen on all devices and this is REALLY a problem as that's where you see reference links and more detail plus amended information you can't see on just the video alone. Always watch technical videos on your computer not your smart phone. The video above was linked in annotation at the point of time I put wrench to tappet as I did not have to actually make adjustment on my bike during the check. If my valve clearance tutorial now the driving force of hundreds of subscribers to my channel has lead you to think a socket was the choice of tool to tighten that tappet you must let me know please. The vid may have to come down.

It is noted the guy performing that adjustment did not use a torque wrench and clearly has experience with GY6 engines. I too will go by feel with my next valve clearance adjustment. It won't make me a whisperer but this is an awkward, delicate procedure that gets me closer to being one

Taking the engine apart seems like a good winter-time project, and you have a nice long winter in Minneapolis. Buy yourself a service manual, and solicit advice on what else to fix while you have it completely torn down. (maybe upgraded rear shocks? Retrofit some kind of easy-out underseat storage compartment?, etc.)

I feel a lot of pain when I read reports of nuts being dropped and lost, especially when it comes to engines. When I was in college I had to take the top end of my car engine apart and fix the broken camshaft. Nothing like coming home late and physically sitting there under the hood with floodlights while trying to make sure no nut ran amuck. Talk about scary. I just knew I was going to lose something. Luckily, when I dropped tools they fell all the way through to the ground, and I never lost any nuts or bolts. I hope you find that displaced little piece of trouble.