Tuesday, January 26, 2010


On wednesday, i was bored, and still frustrated with not having fixed the leakage issue on the ciao, so Alex, Joel, Jimmy and I tore it apart again (I can get the whole engine out in about 7 minutes now, most of that is removing the pipe) And I was finally able to figure out what was going on. In addition to the Decomp valve still leaking quite a bit, It appeared that when I used the face mill on the cylinder, It cut unevenly where it caught on the edge of the broken off fin. I should have broken or ground that fin off to start with, but you live and learn, eh.

Back in the machine shop, I took the cylinder and lined it up in the lathe, clamping the cylinder skirt. I was in a bit of a hurry to finish it up, and forgot my rule about doing this sort of thing... you have to run a piston inside the skirt or it will break the skirt off. I just had to take a few .001's off, so i wasn't too concerned, but when i started up the mill, some boner had left the feed engaged and right away the tool ground into the face of the cylinder and did this:

What a buzzkill.

I also went ahead and took the head down a couple .001's, which was probably a bad idea because now the extra tall piston i made is hitting, so i'll have to machine that stupid thing down again.

Yeesh, look at that nasty decomp, no wonder it was leaking, carbon and gunk all over...

Oh well, thats mopeds, should have left well enough alone when I had the chance. It looks like the cylinder will be fine with the skirt broken off, but if it eats it, I'm on the lookout for a new stock vespa cylinder. Anybody got one they'd like to get rid of? I've got a parts grande lined up, but i'm pretty sure thats a 10mm pin bike, so i'd rather not back track and rebuild another whole engine.

The good news is, break-in appears to be going well. I was concerned about re-using the old rings, but i cleaned them up with a little sand paper, and re-honed, and it looks like they are sealing really well. Given the wierd compression issues, i was worried they hadn't sealed, but this pic says it all:

The transfers also seem to be pretty well matched, the burn pattern on the piston is a little bit dark, but i'm 99% sure thats because of the wicked air leak causing things to run a bit hot.

You can see on the piston the hot spot from the decomp valve leaking (also perhaps because of the wierd head shape around the decomp) and there is a big black mark where the head wasn't sealing that well. Hopefully cleaning the decomp again and fixing the sealing issue will take care of my shitty low-end and maybe even 'fix' the misfire situation.

Thursday, January 14, 2010

Mysteries of the universe. of mopeds.

Recently I discovered the library.

Rediscovered, is more like it really, I used to spend a lot of time in Eau Claire's LE Phillips Memorial Library reading and perusing all sorts of interesting things, but since coming to MSOE and signing my life over to the forces of homework, lab reports, and other such nonsense, I haven't really had time to waste on fiction. My dynamometer research got me back in the MSOE library where I found the amazing and mysterious TJ section. Titles like 'The design and development of 2-stroke engines' have completely rocked my world and dominated the last few weeks with knowledge I had, until lately, just grasped at.

In the upcoming weeks, I'll be spending as much free time as i can spare reading and distilling all this crazy knowledge, for you, my lovely readers. I just had the bomb of knowledge dropped on me in a big way, not to mention a lot of orders for machine work, and some interest in some of my other lesser-discussed projects, so it might take me awhile to dig out, but trust me, it will be well worth it.

Also, in the world of the ciao... massive head leakage, i think it has a lot to do with the decomp valve which i suspected was leaky-weeky, top speed so far has been a shy over 42, but low end is miserable, and compression is very low. I'll have this written up also as i get a 'round tuit'

Friday, January 8, 2010

Moped tuner/machinist for hire.

After a few recent conversations, It has occurred to me that I'm not the best self-promoter or businessman. Its apparently unclear here and other places I post my knowledge, that I do moped work for-hire. I spent the summer doing repair work trying to pay the bills, and since I'm still under-employed, I've got a lot of time to hang out in the workshop and make things faster.

My standard shop rate is $30/hr, for just about anything. Fabrication, welding, custom parts, adapters, manifolds, exhausts, if you've read the blog you know what I can do.

In addition to that, some services I commonly perform have flat-rate pricing:

Cylinder head milling: $25/ on-center spark plugs, $35/ off center spark plugs, $30/ Garelli and Minarelli heads with recessed sealing faces. All heads are custom machined for a specific bore and compression ratio, with 2-angle squish band.

From Machined Heads

Stock-cylinder porting: $50, you specify performance characteristics, I compute ideal port map. Jobs requiring additional machining extra.

Dellorto SHA or Bing carbureator boring, up to 7/8" (15.8mm): $20, plus any time spent cleaning/disassembling carb. This is performed to a mirror finish with a boring reamer, I will also remove and modify dellorto emulsion tubes.

Case-matching: $40 + gaskets. Shown is metrakit E50 with additional transfer porting.
From Metrakit Nate B

My gmail address works well for contacting me. I turn stuff around pretty quick, usually a week or less, but it depends on how busy I am. Email and discuss things with me, everything is custom, so Its my priority that its done just right for your build.