Modern Vespa

I finally listened to the video.

That is coming from inside the engine.

The simple solution is to ride your BV .

Bill

Erm, thanks, Bill. I beat you to it, lol.

I'm going to have a go at making it better before I turn it into a coffee table though.

I'd recorded another audio...perhaps overkill, but tried to get better sound.

Not getting much specific input, which would help. I guess it's time to check the valve clearances for starters...right now waiting for the weather to warm up a bit so I can actually enjoy being in the shop.....

Yeah, all right, it's been a while, but waiting for more inspiration, warmer shop temperatures, and well, there's the art of procrastination.

GTS has been sitting patiently. I was reading another thread last week (which I can't easily find now) with noise that turned out to be valve adjustment, which left me slightly hopeful that something was wrong there. Opened my YouTube recording, thought I was opening the recording from the other thread and thought, "Eureka! That sounds really close!" Then I realized I was comparing my recording to....itself. FFS. Anyway, IIRC, the sound was related to pretty significant cam wear, and mine were thoroughly inspected with the head gasket job.

Anyway, stumbling forward, guess I'll check valves, relatively easy and it's on the way to the rest of the engine work. I don't want to think about where I'm going from there, but I'm pretty sure the noise is internal....first things first.

I assume you've read this thread?

Need help with GTS 300ie Engine Noise?? tinging? knocking?

Yes...pretty sure that's the one I was looking for. I'll go through it again tomorrow....but for the record I just had it apart last year and looked it over repeatedly, including inspection by a mechanic friend.

Well, a bit embarrassingly I've been walking past my project longer than expected...thinking any day I'll write here and see the orange bar saying "it's been xx days since there's been a post" or something. But alas, life, gardening, etc, gets in teh way.

But I'm missing my GTS and the weather's great. Appreciate the suggestions up to now, but it's time to dig in. The question I have is whether there's' anything I should be doing before digging in. Should I be testing anything like compression etc, or will I just be disassembling and looking for wear, such as signs of piston slap or play at connections? I feel capable with the basic mechanics, but pretty green at diagnostics.

Also, wondering how deep I should be planning on going? Last year my concern was over the coolant leak, and wasn't too concerned with looking around for other problems that weren't rearing their heads at the time.

Appreciate the insights of anyone who's been down this path before!

One thing at a time, I'd say.
I mis-adjusted the valves on an MP3 250 once, wrong top dead center.
Clattered like .
On rechecking I found out the root cause, corrected it, and back on the road.

Thanks...that's my plan, though I don't want to get too optimistic....

Well, it's taken an embarrassingly long time to get into my valves....first I procrastinated for warmer weather, then there were some days that it was punishingly hot (at least in my garage), along with all of the other things interfering. So here we are. Scooter's jacked up, valves exposed...aaand, yeah the intake clearances are too large. At least according to my assessment this time. Funny, I had the exhaust ones spot on.

Anyway, plans are to button it up enough to run it and see if, hopefully, the extra little clatter is gone. Fingers crossed, because if not the engine comes out again. At least it's a lot cleaner this time!

One question that's been floating around in my mind is compression testing. I haven't heard it discussed much, or at all here on MV. Wouldn't it be a good way to assess piston/rings wear? It's nightmarish enough removing the plug, but getting a tester on can't be that bad... Just asking in case I decide I need to look further....obviously before I start yanking the engine. At that point it's all visual inspection....

Anyway, I expect to have more news tonight, so let's see.... I'd love to see Madison Sully be right.

I like leak down tests. A compression test can indicate an issue but a leak down test can help isolate. Your filling the cylinder with air, if you hear air coming out the intake or exhaust it would indicate a valve issue isolated to where you hear the air. If it's rushing into the crankcase things are not well, you will have some leakage past the rings but the gauge on the tester will show you if it's within range. You can purchase for a reasonable price on Amazon, Harbor Freight, etc.

I tried to attach a leak down tester to a GT200 once. Even with my tiny boneless hands, I came back with bloody knuckles, mumbling 'Eff this". I could only see that happening with the engine out of the frame. And there was no reason to pull this particular engine.

Hmm, with my paws I think I'd either need a blood donor or just give up and pull the engine.

I'm still laughing at this, never heard that one before

Umm, okay, got to put things together enough to run the engine, small celebration when I drew blood installing the spark plug cap. Started it up and, sadly, sounded about the same.

(I was playing the recording with my wife sitting next to me, and she spontaneously stated "That doesn't sound good...." So I apparently have an independent opinion, )

So if anyone wants an updated listen, here goes... Looks like the next step is pulling the engine. Not exactly looking forward to it, but I'm at least getting experienced. Not sure where I'm actually going from here, but I guess a deeper dive into the engine, expecting I may need to at least look for signs of piston slap, replace rings? Maybe new top end? Hoping I don't need to go much beyond that.....

Really appreciate any words of wisdom, thoughts and etc.

Wondering too, if there's any indication of how dire the situation is...I'd pretty much decided to sideline the scooter until solving the issue, though curious what risk further riding would entail.

Wow! That noise is quite disturbing to hear, even with it not being my motor making it. Hope for the best, and be able to accept worse.

On the road again..... (With a nod to Willie).

Well, it's not like it sounds..not literally, but I did finally wrestle th engine out, next step is getting down to the piston.

Greasy wasn't sure, but thought it sounded like piston slap possibly. As I'm approaching uncharted waters, is there anything to be watched for on the way? My objective for today is get the camshaft out and piston exposed to have a look at the barrel surfaces. Should have looked more closely last year, but I was focused on the head gasket.

That sounds like there is something in the cylinder that doesn't belong there but you'll find out soon enough.

Are the valves still adjusted to spec, .004 and .006?

this. check first because it may provide clues to the where, how & why of the sound.

it was hard to define in the video, but it didn't present to me like top end noise. I'd guess piston slap or big end bearing. but I've been wrong before!

I blew up the pic and looked and the jam nuts and lash adjusters and nothing seemed crazy obvious, also looked at timing on cam gear and hope it's not at TDC compression.

I'll have a look again, (easier now!) but I did recheck and readjust just prior to starting to pull the engine and they were fine.

could you clarify that? I'm always a bit fuzzy about TDC in the first place....

It's a four stroke so you will have TDC (top dead center) on the compression and exhaust stroke. When setting the cam timing you will want the piston at the top of it's stroke, piston all the way up. They will have some sort of alignment marks to indicate this on the flywheel, greasy is your guy for the marks.
When the piston is at the top and the cam is out it has no idea which part of the stroke it's on, could be either intake or exhaust, timing the cam will determine that. There's more but short answer, piston at the top, crankshaft marks aligned, camshaft mark aligned.
I belive your cam gear will have two marks, 2V and 4V, make sure you use the correct timing mark of 4V (you have a 4 valve head). Also make sure the cam chain slack is at the tensioner side when setting the cam timing. If you have the slack on the left side (looking at the engine on the variator side) when you turn the crankshaft CCW and it takes up the slack you can be off a tooth on the cam timing. After you set the cam timing and reset and install the tensioner rotate 720 degrees and recheck your timing to be sure it's correct.
If you need more information I'll try and explain as best I can.

The arrow needs to line up with the center of cam assembly. That said, I would think there should be a second arrow that has 4V next to it (that's the case for 250s) and that is the arrow you want. Regardless, you can confirm TDC through the port on the coolant pump side (or, at least you can on 250s).

we covered the TDC alignment fairly in depth previously, so I'm mostly confident that it was spot on.

these can be assembled with a tooth off on the timing, but the critical tolerances on these are such they won't run. or at least they won't run well or for long...

Thanks, guys.

I do know how to find the mark on the coolant side. I didn't know the detail about the chain...in other words, rotating the variator clockwise will get any slack where I want it? Guess I need to review that.

phaskins, the arrow drawn is pretty much at the 2V marker, the 4V is harder to read, but it's about 15 degrees clockwise from the 2V.

I have to reassemble a bit to recheck valve clearances, but it's getting late and the garage is 90F with 90% humidity, so may or may not get to it tonight...stay tuned.

Not really, if you turn the crank before the gear is on you won't be at TDC anymore. Just be careful install the cam gear without moving the crankshaft from the alignment marks. It will be easy to notice because the cam won't line up properly if you're off a tooth. I don't want to make it sound harder than it is, just take your time. You did it once you'll get it again. Just recheck your work before buttoning everything up.

Are you on the reassembly stage? If so what did you find to be the cause of the noise?

Nope, the opposite. As noted earlier today, just got the engine out. Arggh. No. On the bench its pretty clearly more like .006 and .008. I'm still trying to figure how I could be so far off...I checked it several times last year when I changed the head gasket, and just checked it again a couple of weeks ago before pulling the engine. I'd have sworn I had it nailed at that time.

Soo, now what. Wiggling the rockers I can make noise....sigh. Is it possible to blame that on the rattly noise? Problem is, if we go on that theory, i have to put everything back together to find out.

that's obviously wide of spec clearance, but I couldn't say with certainty that's your cause of noise. cause of a noise, sure; but thee noise? dunno.

unfortunately, you're at a point were you wouldn't know unless you knocked everything back together and tested it.

seeing where you're at, I'd probably say continue forging ahead with the investigation and see where it leads you.

Considering that getting this far is probably the biggest PITA and coming back to this point if that isn't the problem, I tend to agree.

Let's hope this weather calms a bit...first getting smoked out by Canada, now heat and humidity to grapple with. And I thought a cold garage was difficult. Maybe time to distract the missus and set up on the coffee table.

Just a couple of thoughts before I head off to bed....curious, time-wise, what percentage I'm into this project? I'm guessing over halfway? Also thinking it's easier going at this point...if so, I'm encouraged to keep going.

The other thought is that the noise emerged fairly quickly after replacing the head gasket, and if it's logical/likely that the noise is more likely error than wear? My low oil episodes were several years ago, maybe 5-10K miles. Or, do things go south abruptly. It's a different category, but JKJ's BV was running just fine...until it wasn't. h

We need some more information from you to correctly answer this question.

https://www.blueprintincome.com/tools/life-expectancy-calculator-how-long-will-i-live/

At the rate I'm going I'm likely to work through the hottest and coldest days of the year.

You're getting there but not at the halfway point yet. You'll cross the threshold when you start to reassemble.

When you put the cam gear on the chain just keep tension in the CW direction on the cam gear and that will put the slack where it needs to be, tensioner removed. Slight tension, not so much that it moves the crankshaft off its timing mark.

I would also recommend you continue, the noise sounded hard, not the higher pitched ticking sound of excessive lash but anything is possible.

Gotchya!

Heyyy...

True, that, I was mostly thinking about the disassembly phase.

I see it as like going into a cave....coming out again isn't necessarily easier, but a heck of a lot more motivating.