Modern Vespa

I reciently rebuilt my engine with all new bearings, seals and gaskets. I went with the longer cam and Malossi 210 cylinder. I also put the venturi and pod filter on. Now after running the bike for awhile oil and or gas is leaking and collecting on the back of the engine. It is enough that it got on the rear breaks. I checked that the carb is toqued down and everything is tight inside the carb box.

I made sure that the plug that covers the idle mixture screw was new. Am I missing something or what could be causing the issue? The only thing I found odd is when I run the bike with the carb cover off there is over spray when reving the bike off idle.

Make sure your clutch cover is tight. Mine was loose and had this same issue just last week. It's been much better since I tightened the bolts that hold that on.

Usually this is blow back from the carb. Even stock engines have a litte dribble over time. Badly jetted engines have it worse. Generally it's a feature.
What jetting you have? And which malossi 210 kit?

Also, what's your ignition timing? How'd you set it?

Malossi sport kit MK 2 pn:31185910
Mazzucchelli long stroke crank on:45020000
Polini air intake venturi and filter on:20301520
SIP Vape road 12v DC ignition pn:51007RD0 set to 18 degrees (buzzwangle)
BGM PRO Faster Flow Dellorto / SPACO SI24/24E- Vespa PX200
BGM Pro Superstrong 2.0 CR80 Ultralube SPORT clutch
BGM Big Box exhaust

Head gap: 1.3mm
Spark plug B8ES
Main jet stack: 160, BE3, 148
Idle jet: 38/120
Mixture screw: out 1.5 turns

Thanks for the details!

Your intake timings are really tame, your ignition timing should be good.

That jetting says something else isn't right, though. Did you drill the float passage? If not, then that massive main won't make a difference.

How's the rotary pad look? A damaged rotary pad is another culprit that I forgot to ask about.

Have you done a pressure test (make sure the motor has no air leaks) and/or a leakdown test (make sure the rotary pad is sealing effectively)?

Aren't the BGM carbs pre-drilled? Where did I hear that? Hmmmm.....

The last "pre-drilled" carb I bought, which I think was from SIP, wasn't.

If it *is* pre-drilled and running with that main, that's probably worse.

Mechanical set up great. Ignition timing great. Carb jetting oh dear. Lucky it hasn't blown up. Drilled or not, that won't survive any long wot run without some kind of damage.
Minimum jetting AC120/BE4/130 55/100
If the engine is still good it could need a richer AC.

GD dude, a 148? surprised it doesn't smoother itself out with fuel.

It ran pretty good over the weekend at the Midwest Classic. Checked the plug and it was a slight brown. The only time I noticed an issue was coming back into town I stopped to use the bathroom. So, I really got to open it up a little 7 miles outside of Hermann. It ran great up to 50 in 4th gear. Above that it bogged out or ran out of steam. I hit 52 once but it just couldn't get past that. That could be a gearing thing or a main jet thing. I don't know yet.

Over the weekend I noticed the oil dripping. The engine was built and installed the week before the rally and only had like 10 miles on it when I showed up.

I was at that "rally." i rode an Augsburg GS150. I stayed 12 miles outside of that village.

i would back off the main jet about 15 points. that's a start anyways.

Similar set-up here but Pinasco 225. Standard carb jets except 138 main. Iridium B9 plug. Others around me have 135 main. Hope this helps.