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.

Fuel consumption check

Haven't posted in a while. I'm still alive, just ran out of cash and enjoying the summer weather. Anyways, the issues with Fiametta are cosmetic, so makes more sense to just keep riding while the weather is nice.

Just another fuel consumption check at the moment. Just did 186.7km on 5.54L of fuel = 2.967L/100km = 79.28 US miles/gal.

One thing that I've been thinking about lately, is how many km does this Vespa go on 1L of 2T oil? I'm waiting and waiting and waiting for the thing to get low on oil. If I recall correctly, it should burn only 2% oil, so target would be 1L oil per 50L of fuel. 50L/3*100=1666.67km per L of oil. I filled up the oil when I first got the scooter, then topped if off later finishing the bottle. So it makes sense that it's low, but man I'm nervous about running the thing without oil. Of course is a little window gauge that shows there is still oil. When I pull off the cap and look into the tank I can still see oil. Should start getting low soon...

Vespa PX 125 front disc brake master cylinder rebuild

Fiametta has a problem. She just can't stop herself.

She's been this way since I met her. The rear drum brake works fine, but the front disc brake works intermittently. Front braking goes like this: a little bit of braking, slip, a lot of braking. Really jerky stop/start sort of reaction. So it seems pretty simply, just replace the brake fluid. Except when I saw this seal:

And I figured, that is a pretty good explanation for why the brakes have water/air in them and/or fluid leaked out.

Thankfully a master cylinder seal set costs about 40 zloty or about $11.

First I'll take the front wheel off

This is mainly for convenience to get at the brake caliper

I've loosened the bleeder screw in the above pic, once I take the master cylinder cap off, the fluid really comes out.

Here are the ruined seals of the master cylinder:

The new seal set

How the master cylinder gets assembled

Whew, took a little vaseline to get that all together

Assembled including the new gauge o-ring and cap seal

Put some bearing grease on the brake lever

Reassemble and we're good to go!

To answer Joe's question from the comments section, this o ring:

Seals the inspection window which shows you how much brake fluid you have

This translucent (it isn't perfectly clear) plastic part gets inserted from the inside into a hole in the front of the fluid chamber and secured with a spring clip.

The cap seal

goes on top of the fluid reservoir under the metal cover

Vespa PX 125 Gearbox oil change

Pretty simple task, but worth doing, since Fiametta (that's my Vespa's name) is new to me, and I don't know when or if the oil was last changed.

Engine cowl off

Loosen drain bolt

Let oil run into some sort of pan. I did this task with the engine hot, to get as much of the old dirty oil out as possible.

Reinsert the drain plug. The filler plug is this shiny flat head screw.

With filler plug removed.

 

 I bought SIP SAE 30 Gearbox Oil from the Vespa Cafe Krakow.

 Yeah, unfortunately it's not going to be as easy as this video.

The filler tube is larger than the filler hole, so I'm going to have to jam a tiny funnel in there

And squeeze the bottle to push the new oil into the gearbox

Tighten up the filler plug and that's it.

Restoring plastic

I've tried a few different products for restoring the plastic and rubber parts. The cockpit sprays and cleaners work great on the rubber parts, but nothing seems to clean and restore the black molded plastic.

This is after trying a few different products. I did some searching and found an interesting video on Youtube about using peanut butter. No joke. So I took this part off

Got a rag and some creamy peanut butter

And wouldn't you know it, it works like a charm

So obviously this isn't going to repair any scratches or wear, but at least it restores the color of the plastic.

For a couple $$ it's a pretty nice result