Cleaner = slower?!

Ok, I'm a little stumped by this...

I took it upon myself to clean my engine on my Grande and get it ready for some new parts that are on the way.

After the cleaning it runs slower. Much slower. About 5mph slower.

However, it started running slower when I did a test with a new jet. At that time I figured I was just running rich.

Here's what I did in the cleaning (carb is already clean):

I cleaned off my head. Got the gunk off and out. There was a little bit of carbon buildup near the plug, but it came off pretty easily.

Took off some of the carbon on the top of my piston.

And I cleaned out my exhaust port. Just the little tube that my exhaust connects to. I cleaned it out with a wire brush.

Couldn't find any air-leaks but I could be mistaken. I didn't have a gasket from the head to the cylinder and I put the decompression rod back together pretty tight.

So, I don't get it. How can I be running slower? It runs smoother now, but there's not nearly the power, acceleration or speed that I had before I cleaned it. Could it be that I really lowered the compression that much?

What to do!

Re: Cleaner = slower?!

Unless you had a 1/2" of carbon I doubt that had anything to do with it.

Put the original jet back in and see how it runs.

Re: Cleaner = slower?!

The original is back and I don't know what's up with it.

Re: Cleaner = slower?!

Mr. Richard Dickrich /

Check your compression. Probably lost some if the head is not on tight enough.

Re: Cleaner = slower?!

gasket! you are probably loosing compression from not having a gasket. It needs to be sealed better than just cranking it down.

Re: Cleaner = slower?!

Hmmm. I'll give it a shot. I just don't see why it worked better before. The head wasn't even put on as securely as I put it back on after cleaning.

In fact, there was a leak before I cleaned it.

Re: Cleaner = slower?!

sometimes an air leak can make you go faster. try putting in a new sparkplug buddy.

here's a little rhyme about rich and lean performance.

the leaner you are, the faster you go.

you may risk seizing, but at least you're not slow!!!!!!

Re: Cleaner = slower?!

That's another thing I forgot. I AM using a new plug. It's crazy, but whatever.

Oh, and I like that rhyme too. I'll try to remember it.

Re: Cleaner = slower?!

lee, you're a poet.

Re: Cleaner = slower?!

Oh, so it was a leak. Apparently the gunk I cleaned off had made a seal that was aiding in my compression. I made a temp gasket for it until I can order a real one, or make a better one. And that will probably wait for when I get the head milled.

Re: Cleaner = slower?!

There are no head gaskets for Vespas. They only have base gaskets. Something to think about.

Re: Cleaner = slower?!

babycakes, you make that up?

Re: Cleaner = slower?!

You could always use copper seal, spray or brush on prior to installing the head, it will seal a minor leak.

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