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Post by 90GTVert on Jun 5, 2016 15:05:47 GMT -5
Ideally, you want to control compression via the combustion chamber design and keep the squish tight. Real world testing on my Minarelli junk, I couldn't tell the difference either way... but still I try to open up chambers these days just to go with what should be best by theory and the experience of people that know more about it than I ever will.
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Post by niz76 on Jun 5, 2016 15:19:59 GMT -5
Your port timing change has me scratching my head!More deck clearance should mean a dome below the ports at BDC(shorter pin to piston crown height,but NO!Shorter crown height is like stacking base gaskets=more duration..But we have less duration???STRANGE!! Having a lot of squish clearance invites detonation as the flame front can easily move from the combustion chamber to the piston edges,,not what we want... Exactly! I really wish I would've compared the two pistons side-by-side. I would pull the Grand Sport piston back out but I painstakingly prepped the sealing surfaces so nicely, and the copper spray on the head too... I just don't want to undo all that nice work lol. If I look back at the older pics I think I can see that the Grand Sport piston is actually a little bit taller. It doesn't go as far below the ports as the Polini did, and also doesn't sit quite as far below deck as the Polini piston did, therefore I lost a few degrees of duration...      |
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Post by 190mech on Jun 5, 2016 18:50:38 GMT -5
The GS piston looks much better at BDC,youve just got some mild porting there,I'd run it as is(I know you are!),then adjust from there..Hope your new iggy gizmo(dont know the Vespa lingo) gets it all running strong so you can doll her up with some make up and earrings so all the fellas smile when they look at her!!
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Post by niz76 on Jun 5, 2016 19:41:52 GMT -5
Hehe I don't have the gizmo just yet but soon! Ya I gotta get her running strong as I have lots of ideas to doll her up. Gotta use these decals ryan_ott sent me! |
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Post by niz76 on Jun 7, 2016 21:36:02 GMT -5
Good News- This time we passed the leakdown test with flying colors! I really like this new clutch side seal a lot better than the one I originally installed. This one is the all rubber type without the steel ring impregnated into it. Sweet!
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Post by niz76 on Jun 9, 2016 20:17:51 GMT -5
Dang don't know if old age is catching up with me or what but I've been moving slow on getting this scoot back together again. Actually I think it's the fact that Tropical Storm Colin really put a hurtin' on my pools this week and put a butt kickin' on me too! I brewed a real strong pot of coffee after work tonight and got down to bidniss. Made a little progress- engine is hanging in scoot. #smallvictories....  |
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Post by ryan_ott on Jun 9, 2016 21:57:53 GMT -5
Strong coffee... Yum
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Post by niz76 on Jun 12, 2016 12:46:33 GMT -5
I got everything back together on Friday and went for a few little short rides around the hood keeping the RPM's a bit low just to let the rings seat nicely. Yesterday I did a lot with the electrical and finally got everything working correctly. The light finally runs off the stator and I don't need to run it off battery power anymore! She seemed to run great so I decided to get suited up (changed my flipflops for tennis shoes) and go for a decent ride. Well, I made it about 2 miles and she started misfiring and kinda sputtering. I recognized the signs as the plug fouling so I pulled into Advanced Auto to buy yet more B7ES plugs. I probably have 50 plugs for this thing. (It likes the B7's better than the B8's). I spent the next two hours in the Advanced Auto parking lot trying to get it started and running enough to limp it home. I could barely get any spark. The ol' faithful homemade Minarelli CDI/GY6 coil did better. I bought a spark tester- the kind where you lengthen the gap and see if the spark will jump it. The Vespa CDI would barely jump any gap and the spark was orange. The Mina CDI jumped more of a gap and it was kinda bluish. The only plugs I could get to even work and start the scoot were the two that I had "side gapped". Even the brand new plugs wouldn't work... Once I got home I tested a few things and it seems that the fancy dancy new ACCEL plug wire was to blame. The old stock plug wire works much better and I can consistently jump a large gap on the spark tester with a nice blue spark now... I also realized that my battery wasn't charging- it was nearly dead after only this short ride?? Grrr... Well I at least installed the led rear tail/brake light that I bought a few weeks ago to help with the load. Seems I haven't quite exorcised all the electrical demons yet...  |
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Post by acvw74 on Jun 12, 2016 14:37:07 GMT -5
"I also realized that my battery wasn't charging- it was nearly dead after only this short ride?? Grrr... Well I at least installed the led rear tail/brake light that I bought a few weeks ago to help with the load. Seems I haven't quite exorcised all the electrical demons yet... "
Ahh the joy of owning an Italian bike. Completely mental...followed by insane awesomeness!
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Post by niz76 on Jun 13, 2016 0:00:04 GMT -5
"I also realized that my battery wasn't charging- it was nearly dead after only this short ride?? Grrr... Well I at least installed the led rear tail/brake light that I bought a few weeks ago to help with the load. Seems I haven't quite exorcised all the electrical demons yet... "
Ahh the joy of owning an Italian bike. Completely mental...followed by insane awesomeness!
Probably the most accurate description possible right there! |
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Post by niz76 on Jun 13, 2016 0:12:41 GMT -5
The good news is I figured out my electrical issues- kind of. When I disconnect the wires from terminal 1 on my key switch the scoot runs great. Re-connect and there's my problem. The bad news is that's the connection I have the fuel pump hooked to. It was a little oversimplistic to think I could just tap into the tail light for 12v power to the fuel pump. The way this thing is wired is super funky and that tailight connection makes it's way back to the regulator/rectifier- through the blinker relay??
So Strange. I guess now that everything is working correctly I'll have to wire the pump directly to the battery with a toggle switch up front somewhere- easier than it sounds as it's gonna be a real by@tch to fish the wires through the frame. While I'm at it I might as well run a new kill wire to the CDI to replace the crumbled og one. I've been shutting the engine down by letting out the clutch in 1st gear with the brakes held.
Another side-effect of getting to know my wiring real well- now I know how I trashed my original stator so bad- I was backfeeding 12vdc to the stator through the regulator when I hooked my headlight up to the 12v+ on the keyswitch! Doh!
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Post by bluegoatwoods on Jun 13, 2016 8:24:40 GMT -5
Highly interesting thread, Niz. A great bike, too. But then....it's hard not to like a Vespa.
I've never seen the internals of a Vespa before. I've had that picture in my mind of an engine sitting just a bit further back than on what we now think of as a standard scooter, and off to the right. But now I have a much better picture in my mind's eye of just what that engine looks like.
I don't have time to read the whole thread right now. But I made sure to finish page 10. It'll be a bit easier to remember just where I left off when I come back.
I'm a bit frightened for you over the possibility of a damaged crank. But I guess I'll learn what became of that when I can read some more. Best of luck!
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Post by ryan_ott on Jun 13, 2016 9:56:19 GMT -5
If you use a automotive relay you can power from your battery without a switch. Power from your switched source will energize the relay but pull power from the battery. Just a thought. www.12voltplanet.co.uk/relay-guide.html |
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Post by Florida Antique on Jun 13, 2016 12:05:02 GMT -5
If you use a automotive relay you can power from your battery without a switch. Power from your switched source will energize the relay but pull power from the battery. Just a thought. www.12voltplanet.co.uk/relay-guide.htmlI though about this too. Niz you can pickup a horn relay at almost any autoparts store and use it off your key switch to power the fuel pump. The relay coil draws almost no current so it would not affect the tail light circuit. I can just see forgetting to turn off the fuel pump switch and killing the battery. That would probably lead to another long push home. |
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Post by 190mech on Jun 13, 2016 17:34:18 GMT -5
Would need a bright idiot light with a decal stating "fuel pump on",(perfect solution for a non existent problem),the relay will make it a 'mindless' function!!  |
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