Vespa PX 221 help

[Nik221]

Your engine overheated, have a look at the plug and see if your fuel mixture is poor. It could be an air leak, actually it must be one of those two. My engine is fine still since I have put the Base gasket it goes better. I have a clutch problem it is lurching and I cannot set of right at all and it makes a bad noise aswell but only when setting off. Otherwise everything is good for now

[smiffy1968]

Hi Nik. Yes it overheated and it was neither the timing or an air leak. Carried out a leak down pressure test of engine, all good. Again checked my timing using a dial gauge and strobed it up correctly. I added an additive called Ethanol Shield for stabilising the Ethanol in fuel from running two strokes hot and fired up the engine ran it for a while and the tickover rpm settled back down to normal. I have since taken it out for a damn good thrashing up to late 7k rpm in third and straight into the power in fourth at just under 60mph/93'ish Kmph. It's flying. Just for my own piece of mind i have a Trailtech TTO Cht temp gauge arriving on Thursday. Before i head to a local rally. I will let you know how i get on, there is a 3 mile stretch of road i can test it out on, on the way to the rally. Cheers. Hope yours is still well.

[Nik221]

That's awsome, keep me up to date ride safe !!

[smiffy1968]

Hey Nik, i managed to get to the Rally and back. Won a trophy too. I wound it up over the dual carriageway and hit 70mph easily. Temp hit 200C though so backed off. Ordered a 1.5mm packing plate and some bigger main jets. A 132 & 135. See if i can get the running temp down. Have you fitted the packer under your barrel yet?

[Nik221]

That's great news. Yesterday I did a 200 km trip and noticed that the engine is nicest to sit at 100kmph but that was with my brother sat behind so could easily be cruising at 110. The power for me is better with packer under the barely. Today my bigger carbon has arrived a phbh 28 so will be playing with the jets a bit. Hopefully the power will be quit a bit more. Cheers

[smiffy1968]

Yep, i am going to jack the barrel up 1.5mm as well. More power! Waiting for the parts. Phbh 28 carb should chuck more fuel into your induction. I may end up going that way as well, along with a fuel pump. Sounds like yours is running sweetly.

[Nik221]

It is i have to say i wouldn't go the full 1.5mm though. Go 1mm base and 0.5mm head gasket. You don't want to be without torque.
Do you think a fuel pump is necessary ?

[smiffy1968]

I'll see how it runs. Playing around with it really. Many do not run a fuel pump. I am still not decided on the gearing yet either.

[Norrie Bodge]

Go 1mm base and 0.5mm head gasket. You don't want to be without torque.

i found 1.2mm packer & 0.5mm head gasket best setup for mine, v nice torquey motor..

[Nik221]

And what's your squish band? Today I put my phbh 28 carb on and I have to say what a bloody difference!! I can't explain the difference!!