Modern Vespa

Morning everyone, so my gts has developed this annoying engine ticking sound, it goes up with the engine revs and sometimes you can hear it on tickover, ive replaced the whole waterpump stator plate cover assembly hoping it was a moody bearing but its still there, ive done 2 oil changes on it in 2 months and zero crap in the oil strainer, i even cut open the oil filter casing last night to look for any brass debris but it was clean as a whistle inside the paper element, the bike has 16300 miles on, full history and purchased from a friend, ive adjusted the valves so they are spot on 0.10 and 0.15, the bike has plenty of power so i dont know what to look at next, it had new rollers and belt at 15000 miles

How do you adjust the valves? I want(say 0.10) a 0.09 to have no drag, 0.10 to have light drag, 0.11 heavy drag and 0.12 won't go in.
If I make an adjustment, I turn the motor(by hand) about 6-10 revs and double check. Then I double check again. Put a few drops of oil on the cam lobe when doing this. This puts some pressure on the rockers that doesn't happen if you adjust and button it up. I have had to re adjust before. I have some OCD when it comes to motorbikes.

I just copied the vespa motorsport video, the one with the Robot fella, i did them with slight drag just like he did, the engine made the same sound before i did them thats why i was hoping it was the waterpump bearing, the noise is annoying and the bike perfoms very well so thats confusing me, poxy thing

have you taken a visual look at the cam journals themselves?

I had one that would adjust in spec, but the journal (and corresponding rocker) was worn and would tick away now matter how many times I checked and rechecked.

while you're there, I'd have a look at the timing components- wheel, chain, decompression weight, and make sure all of that is up to snuff.

from there, I'd make my way to the transmission side of things and see what's up.

good luck!

It might be worth giving the exhaust/manifold/headers a check as well.

I had a honda that made a ticking noise and it was a pinprick hole in the exhaust, right by the engine. It went from a tiny rusty hole to completely disintegrated in the course of about 500 miles.

(Not clear to me what you mean with "tickover")

Now you say it goes with engine revs.
Can you influence it by the throttle? Low throttle: hardly or no ticking, full throttle: hard ticking?
Or while riding you slowly loosen the throttle and at some point the ticking is gone but returns when you close the throttle down.

Or is it independent of the throttle?

So you can hear it when the bike first starts up , the sound increases with the engine revs whilst riding so the more throttle the louder the ticking, with the engine warmed up it makes no sound when the bike is stationary but will increase if the engine is revving up, ive now ordered new cylinder head exhaust studs and copper gasket and new nuts and will examine rhe manifold or might order a new sip stainless manifold to rule any of that out

That does not sound good. When at idle and warm there is no ticking noise but the engine then does not deliver power.
I don't want to be pessimistic but it could be a problem with the crankshaft bearings or the connecting rod bearings.

So ive done 2 engine oil changes since this started, oil stainer had zero metal flakes in it both times. So that's good and the second time i cut open the oil filter to check for any metal debris and its clean, no evidence of any brass lr aluminium metal flakes so thats also good, also the bike has full power and i mean its really quick still for a 300cc scooter so i might just ride it till something happens

Listen to the fuel injector. Starts ticking when gets old.

Maybe you could try one these.
https://www.amazon.co.uk/mechanics-stethoscope/s?k=mechanics+stethoscope

That's "idle revs" in British.

Ordered the stethoscope, coming tonight before 10pm from amazon so should get somewhere now

OK, that looks reassuring. Probably nothing wrong with any of the bearings, then.

I know this sounds mad but I was hoping to find some brass from the end bearing of some other metal debris but the inside of the oil filter is immaculate and the oil strainer behind the drain plug, this would of proved that something was very wrong

Why wish for trouble when potentially there isn't any...

Just a thought. I know that running the engine without the variator on a Vespa is bad. So try reassembling the variator without installing the belt and rollers. If the ticking stops, it's the transmission.

I wasn't wishing for trouble i just wanted an reason for the sound 🤦🏻‍♂️🤣🤣🤣

Good suggestion. But I would think that if it is in the transmission it should be in the variator, because in the transmission the only part that 1 on 1 follows the engine revs is the variator.
And Leesprint said it goes with engine revs.

Can I come back to this post?
When the engine is cold you always hear the ticking, also at idle, but when the engine is warm there is no ticking at idle.
Is that a correct understanding?

That is correct, cold engine ticking on idle but warm engine no ticking on idle, ticking always with engine revs though

Were the ramp plate sliders(AKA Variator guide shoes) replaced? Heat tends to expand things?

Is there a possibility that you didn't tighten the valve adjuster nut?

i always get ocd about tightened nuts so defo was double checked and then checked about another 5 times, ive ordered a new head cover gasket and the 5 damper washers so i will yet again tilt the engine and check the valve clearance, not sure what else to look for whilst the head covers off ?

If the valve clearance is as prescribed then it is fine and the ticking is not coming from there.

Hello,

Did you find a solution to the problem?
Have the same problem. Found a kind of plastic? rubber piece in the oilstrainer only 1,5mm