Beginning

The Aprilia Pegaso is mostly together

but soon to be mostly apart.

Took some stuff off, and drained the coolant.

The other Piaggio product needs some attention

Er.

I've also got a 1998 Aprilia Pegaso 650. I took it on a long trip to Lithuania in spring, and well, it hasn't been the same since. I started getting a little misfiring and loss of power on the way back, but when I got close to home, it was so bad I was afraid I wasn't going to make it.

I've had tons of various theories about what happened from carburation to electrical, but after troubleshooting everything, it comes down to compression.

So I got myself a compression tester. Ugh, this thing is so dirty and covered in oil.

Ok, well that is somewhat better

It's a 650cc single, so to do the compression test, I warmed up the engine and took the valve cover off so I could tape shut the decompressor on the end of the exhaust camshaft. Here we can see the compression tester screwed into the spark plug hole.

And here is the reading. Yeah. It's either dead or dying. 7 bar is too low.

For a while, Aprilia was making a bike for BMW, the F 650, with essentially the same Rotax engine. There is a great forum for the BMWs. Got some information about compression testing this engine and interpreting the results here.

Key is:

- A new engine should have something between 10-12 bars. After a while this reduces to 8-10 bars. Service is needed when it drops below 7, but you'll recognize that because the engine won't run correctly (no power).

Oil Consumption check

I thought I would do an oil consumption check as well. The engine should burn 2% 2T engine oil. That would mean that if I get 3L/100km, I should get (3*0.02) = 0.06L/100km of oil consumption. Or a whopping (1/0.06*100) 1666km per 1 liter bottle of oil. We'll see. I figure the most scientific way to do this is to run the thing nearly out of oil, so I can fill up a whole bottle, and see how many km I do when I run out of oil again.

So this is what the visual gauge looks like when a Vespa PX is low on 2T engine oil

My test begins at 31620.7 km

And by the way, previously I had used 2-Stroke Oil SIP Formula Race. At 7.20 EUR per liter, I thought this was pretty expensive. So I thought I would try Orlen Mixol S at 3.60 EUR.

NEVER AGAIN!

OMG, what a disaster cheap 2T oil is compared to the SIP stuff. The SIP was literally smokeless and odorless. Now when I go on the gas with a cold engine, I have a gigantic cloud of blue smoke behind me. It's crazy ridiculous terrible bad. When I start the thing up in the morning in the garage, a thick haze fills the air with a sickly smell. The difference in the color and odor of the smoke is easily worth the price of the SIP oil.