Tue Nov 02, 2021 10:20 am

Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 75
Location: Dubai
 
Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 75
Location: Dubai
Tue Nov 02, 2021 10:20 am linkquote
Thanks chaps and appreciate the advice. I will get a variable timing strobe and do it properly. I've taken the route of just tidying up and replacing the rings and at the same time split the cases for the first time to learn a bit more. Replaced seals, gaskets, cruciform, cosa 2 clutch.

I will probably have a go at reducing the squish as well and see how we go. I've also bought a CHT gauge which I will install to keep an eye on the temp.

Any advice on optimal or maximum temperatures. Its here most of the time as it is!

No doubt will be back on here asking for guidance on carb setup and jetting.

Again thanks everyone for pitching in.
Tue Nov 02, 2021 12:08 pm

Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 4244
Location: Nashville
 
Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 4244
Location: Nashville
Tue Nov 02, 2021 12:08 pm linkquote
If you've split the cases, now is the time to build yourself a pressure test rig and make sure you don't have any air leaks before you button everything up once and for all and put the motor back in the bike.

As to temps, once you hit 350f, you should start to worry.

I'm glad to see you're doing this right
Mon Nov 22, 2021 2:04 am

Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 75
Location: Dubai
 
Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 75
Location: Dubai
Mon Nov 22, 2021 2:04 am linkquote
Thanks for the advice as always.

So I bought a variable timing strobe and set to 18 deg BTDC.

Put everything back together and..........

It started 3rd kick, I couldnt believe it!

I have now run in for about 150km and running well. I thought would run in before tuning etc

However, I noticed this morning a little bit of an oil leak. Obviously dripping off the lower part of the case. It is not immediately evident where it is coming from. Where should I start?

Is it just a case of nipping things up? Or do I dismantle and start again?
Mon Nov 22, 2021 7:29 am

Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 4244
Location: Nashville
 
Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 4244
Location: Nashville
Mon Nov 22, 2021 7:29 am linkquote
That's awesome that you're up and running!

As to the oil, I wouldn't worry about it if it's just a drip every now and then. These are dirty motors and prone to a little bit of messiness.

It could just be a little bit of spitback out the back of the carb box at the mixture screw hole or the autolube leaking around the gasket, which is something that's just going to happen.

If it's the autolube, you want to fix that. Pull the carb, see what's up with the gasket, expecing to replace that carb base gasket (i.e. make sure you have a spare before you start), making sure the autolube hole from the airbox channel to carb is not blocked, and seal it all back up.

Make sure it's not the cylinder base leaking, because that would be an air leak and needs to get fixed ASAP.

If you didn't seal the exhaust to the cylinder stub well, ideally with high-temp RTV silicone, that will leak a little and is also a de facto air leak, but less of an issue on non-tuned motors, but will spray sticky schmutz around the bottom of the motor and inside the flywheel & cylinder shrouds, making a nasty mess over time.

The other possibilities are up to you if you want to take that on, but I'd suggest "getting used to it" as a viable long-term management strategy
If you want to track it down, assuming it's gearbox oil, it's probably weeping from one of:
- The kickstart shaft (especially if you didn't replace that o-ring)
- The primary drive shaft nut just below the clutch cover
- The clutch cover
- The clutch arm

You could also be getting a little bit of leakage between the case halves, but I'd honestly be a little surprised if that was the case unless the faces of the halves are marred.
Mon Nov 22, 2021 9:04 am

Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 75
Location: Dubai
 
Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 75
Location: Dubai
Mon Nov 22, 2021 9:04 am linkquote
That's great advice.

There is no autolube so I can cancel that out. It looks like gear box oil. I did change all the seals but I'll have a good look in all the places as suggested and report.back.
Mon Nov 22, 2021 7:45 pm

Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 75
Location: Dubai
 
Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 75
Location: Dubai
Mon Nov 22, 2021 7:45 pm linkquote
Seems it could be from the bottom casing stud and the oil drain bolt. Also there is a bit of oil staining on the back of the rear hub plate. I didnt take this off when opening the cases as I left the motor in the scooter. Is it worth assembling the hub and back plate to change the seals?
Also oil around the clutch cable where it passes through the case. Anything here to worry about?









Mon Nov 22, 2021 7:50 pm

Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 4244
Location: Nashville
 
Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 4244
Location: Nashville
Mon Nov 22, 2021 7:50 pm linkquote
It's not a big deal to pull the rear hub and check that seal. Just don't forget the cotter pin/split pin when you put it back together.

And on the oil plug, you can tighten it up a little bit, just don't go crazy unless you want to strip it out and have to tap it for an M8 plug bolt.
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