Modern Vespa

It hardly takes any pressure at all, really. I've done it by raising the bike pump up and let the handle fall under its own weight, even.

Always check your test apparatus....

I have changed parts on my smoke tester because it did leak sometimes where the carb goes on and did some test today. It leaks a bit where the carb goes again but I stopped that by putting rubber washers on the bolts what hold the carb on and I put grease on top of the engine where the carb goes and now it doesn't leak. I looked around and I've checked the clutch side where you can see the main bearing and I couldn't see smoke. The smoke tester started leaking a small bit of smoke where one of the pipes go in the top so I have put glue around the top of the pipes and I will test it again tomorrow. I was expecting smoking coming from main bearing seal today but I didn't see any so hopefully the main seal isn't leaking so hopefully it just needs a good run to clear it. I did have the cylinder off so I could replace the main engine gasket and I read it will smoke after so I really do hope it's just that.

This is my smoke tester

I used an inner tube Valve and cut the rubber of it the same as the 5mm rubber and shaped them to the bottom of the carb and bolted the carb on top.

Todays first test. Its the main seal im looking for leaks mainly.

Todays second test.

3rd test with a small endoscope camera

3rd test with the small endoscope camera. Can anyone see any leaks in my 3 videos. I cant.

Mobile videos are a bit too pixelated to see much.

The endoscope video I see some weird light flicker at 0:15 which might be the light coming off smoke.

Around the main bearing near the primary.

I think CM said the best way to see if their smoke is to switch off the lights to the room and shine a torch parallel to the place you want to check. So the torch light bounces off any smoke. And you're not shining the light at the engine.

I can see it. It's dark now so I'm going to test it again. The first two videos was my phone with the light on and the 3rd video had a light in.

Video in the dark with a flash light.

Video in the dark with just the iphone light

Can't see any smoke, but you're still pointing the light at the cases, will be hard to see anything…

FFS I got to do it again 😆. Last night I was finish, lock everything up, had a shower and just had my dinner then I read your message so I got dress in my work clothes and had to open it all up and did a test in the dark with a light on it 😆. Right I'm going to do it one more time. I hope yous ent pissing your selfs laughing winding me up 😆. I will do another test by lying the scooter on the right side and put oil on the main bearing and pump up the pressure to see if there's any bubbles. All the this messing about with pressure and smoke testing I could have change the main seal. 😂

Trust me mate, just want you to sort it out.

Did you end up doing the oil test for the clutch side seal? and no soapy water tests?

like CM mentioned before , the biggest challenge is finding it.

the last slow leak like yours my leak was in the intake side... super slow, but soapy water found it after 30mins of messing around.

Honestly, you could just swap out the seal for piece of mind. But make sure its got loctite for a metal seal or loctite retaining compound for a rubber seal.

I'd still be doing the pressure test if you swap out the seal anyways. So youre not skipping anything. But it is slightly strange youre not finding anything super obvious...

it's ok I know yous are trying to help I was just joking 😆.I put pressure in and sprayed soapy water all around to find no leaks anywhere but I didn't spray it in the main bearing. I turned the scooter on it's side put pressure in and put oil in around the main bearing and there was bubbles so the main sear is no good. I'm having a tea break then I am open the engine to replace the main sear. Lucky I have a spare in but I don't have any more gaskets. Can i use the main engine gasket and cylinder and head gaskets again ?

Yeah, if you don't tear them, you can reuse it.

I've never been able to save any main engine gasket though. Usually they rip because they're stuck on.

I'm expecting the main engine gasket to rip but the cylinder and head one should be ok. I will order one later if it does rip.

I manage to get it off in one piece about 50% of the time. I use Permatex Aviation Gasket Sealer, which stays tacky and never fully dries like RTV.

Hopefully you've found your only leak and won't create any new ones in the process of splitting & reassembly. Or get a perfect leak test and then discover you forgot to install the kickstart gear. Or any other multitude of things that can go wrong working on these things.

You'll get there, but it's definitely frustrating road until you do.

I almost forgot the kick start cog when I had it open the other week. Early this year I put my p200e together and forgot to put the cog in 😆. I split the engine today and the main engine gasket it ok so that's good then I don't have to wait for gaskets but I got to wait anyway because I fort I had a spare main seal but it's for a px it's the rubber one so I had to order one it be with me by Saturday. I really fort I have it done today.
As for more leaks I think it should be ok I hope 😆 I've had engines opened up loads of times over the years and never had any leaks.