Modern Vespa

I rarely rev the crap out of my engine, and don't ride WOT very often either, but sometimes I do. My p200 is mostly stock. I've got a Sito pipe, and have altered the idle jet and mixer tube. Today I decided to disable the auto lube for a while to see if there is a difference in the way the engine runs. When I sometimes rev out pretty good in first gear, not sure the actual RPM, but reaching to around 20MPH, the rpms and power will drop, and there will be a slight pinging from the motor. I say its pinging, sounds like a rock bouncing around in the top end when its under a certain load. When I shift out like this, I don't hit 4th gear til around 45MPH. I just seem to have no low end in 4th and can't really rev out good to get past 55 if I don't rev that far in 3rd. Is that normal for an engine to behave this way when "red lining", or should I have a smooth wind up even on the higher rev range?

Did you put in a bigger main when you put the Sito on there?

without a load more info which Im sure guys will be asking for....but a couple of pointers in my opinion....

you say youve changed the mixer and air...but no talk of the main jet. This is the one thats letting the fuel through at anything over 3/4 throttle. Think you may need to up that a few.
Im sure the noise you describe sounds like its pinking meaning running very lean

Definitely upped the main. I'm running a 160 air, be4, 122 main, with a slightly richer idle jet. I assumed that the be4 mixer would get me a richer mixture through the full throttle range. Using this color code https://www.hideandfur.com/inventory/BuckskinColors5Text.jpg I'd say my plug after a long ride is some where between saddle tan and sunset. I definitely agree that I'm a touch lean. Does that jetting make sense? I was always much leaner until I changed the mixer tube. I'm going to run on premix for a little while to see if any thing changes. I understand how auto lube is a good system, but don't believe it's as reliable when you make changes in jetting.

+1 .... up the MAIN.

Bear in mind that if you've disabled the autolube and are running pre-mix you can go down a little on the main jet. e.g. PX200 values are 116 for pre-mix and 118 with autolube. Of course that's with a stock engine, you've fitted a Sito so you need to go back up a couple of sizes. Make sense?

BTW I trust you removed all the drive bits when you disabled the autolube? Disabling without removing all the drive bits is NOT a good idea.

And sealed up all the places air instead of oil may get in

If everything is working right, I would hope oil can only come from the oil line that I plugged, although I understand the gear being lubricated by said oil. If the bike runs better as premix, ill properly disable the cog. If not, I'll up the main to a 124.

Yeah, it's not quite as simple as that. If the oil drive gear is still enabled, then it is still causing a suction in the oil pump. But instead of pulling in oil, it's now pulling in air. Basically, by simply disconnecting the oil line, you could very well have caused the mixture to be too lean.

If you're serious about disabling autolube (I wouldn't unless you're running some crazy tuned motor), then you need to remove the drive gear, plug the hole where the drive gear was (rubber stopper or SIP sells machined aluminium plugs), and finally fill in/seal the oil path on the bottom of the airbox with yamabond or JB or something.

I guess it helps to write something with your reply. So in combination with this thread, and another I wrote inquiring about race fuel. Some one recommended mixing 1:4 race fuel to non ethanol gas. Tried that today and I revved fine into up around 25mph+ in first gear. After shifting into second, the front wheel came off the ground for a second. I haven't looked at the plug yet. I tested compression the other day and was close to 160psi. Is this amount of compression counter productive? The engine definitely revs higher with out pinging and power loss now.

that is too high
if you don't adjust that # then make sure you only use high octane fuel or race fuel.

the higher the compression the higher the octane the engine needs since lower octane fuels would have pre detonation issues.

if you retard the ignition a few degree that would help cool things down