Modern Vespa

Doing an overhaul on my stock 1974 Vespa Rally 200. I forgot to mark the piston before I removed it. Here are two pics of the opposing sides of it. Can I assume that the second one (one hole and sooted) is the exhaust side?



Also, here is the rectifier. I haven't seen one with five rows of connectors (usually there's four). Anyone familiar with this?


TIA,
Bill

are you putting that piston back in?

please tell me you aren't putting that piston back in...

-g

The piston is toast, so it doesn't matter. The new piston will have an arrow on the top which points to the exhaust. That rectifier/regulator is stock for 1974 - 1977, part # 144980. That is set up so your engine runs off ac and the rest of the scoot is dc. I wish you luck with it.

It just came out, hence it's dirtiness. Yes, it's going back in. Fit is good, cylinder unmarred [edit - was "I marred" ... dang spelcheck]. I'll post a pic when it's all cleaned up. The piston question was about orientation.

Thanks for the rectifier part number. I'll try some research on it but I'll probably just keep using it. Adding stock turn signals, too, far all ye naysayers. :p

That's not dirty. It is unusable. If you need come on asking a basic top end rebuild question like "which way does the piston go?" you might want take a step back and listen when people who have been doing this for a while say you need a new piston. Or you can be a douche. your call.

That piston has powered my 210 lbs at 65-70mph for miles on end. The only reason I'm overhauling it is too much oil grime at the bottom of the engine and an air leak, plus time on my hands.

Not to distract from my original question (other respondents are welcome to answer it), but upon what criteria are you all making that call? When I post that pic of it cleaned up (probably tomorrow, just to prove a point), I'll ask the same question and see if anyone wishes to backtrack. Take any piston out after 500 miles and it'll be sooty. Are you suggesting anyone with a sooty piston replace it?

I've been on forums since dial-up CompuServe and Usenet were the only options. I'm a member of at least ten today. Each one has a personality. You are detracting from the personality of this one.

Last sentence unnecessary. Chill.

This post was not quite
What we were hoping to see
Try again, perhaps?

Agreed re: last sentence.

But, OP is showing his naivety on this topic... we don't care how long you have been on what forums or how well the engine ran, that part is toast...look past the soot and really check out the condition, especially the first pic. This is not an uber expensive part to replace, why would you rebuild around a part like that?

Can't find anything wrong with this.

well... you're more than welcome to clean it up and run what ya brung; but that thing looks hammered-ass.

you have metal on metal transfer on practically every quadrant of the component. the darkly glazed side shows what appear to be numerous exhaust side seizes, the alum. smearing and deep scrapes show a typical four-corner seize-- or rather several of those, too.

the carbon build up on and around the rings is excessive, as well as what i can see on the ring lands. the rings themselves show an alarming amount of scuffing for what should be a hardened surface while the amount of blow by doesn't look too terrible, a compression check and leakdown test would probably tell another story.

how does the crown look? how about the underside of the crown?

did you measure the bore? what about the ring end gaps? piston side clearance?

look, i'm not trying to tell you how the cow ate the cabbage, but you're stepping over dollars to pick up pennies. this piston is showing obivious signs of wear, if not downright abuse. running this in anything but the most budget beater of rebuilds would be a huge risk.

think of it from this perspective: you just rebuilt the bottom end, why would you risk throwing away all that time and money to run this top end? cuz, that mess is on borrowed time. either it or the rings are gonna come apart... and probably at speed.

but, back to your original question-- line up the ports in the case with the ports on the piston. but, you should be able to see an arrow on the crown on the piston that points toward the exhaust.

-g

The regulators /rectifiers come with 3,4 or 5 pin, depending on how many power feeds you need?!
All do the same job (but check the power rating - watts )!

I think your bike has a battery. Do yourself a favor and get rid of the battery. I onverted to a non battery bike via instruction on MV easy to do. The battery is a pain.[/code]

Why is having a battery fitted a pain??! They are quite handy if you want any 12v d.c. accessories, especially a decent horn.
It can easily be wired in such a way that even if you take off the battery then everything (engine/ignition/lights etc) still runs and works as they should. Its basically just having an extra wire (power feed from the rectifier) and a battery and an earth wire.

*if you are thinking of running extra accessories it maybe worth running an extra/spare wire (or 2) in with your wiring loom for any future 'upgrades', from the battery area to the headlight area.

odds of seeing the OP back? slim to none?

oh, I'm still here. I cleaned the piston up. intact crown, sharp edge. cleaned out the ring grooves - sharp edges, no scratches. rings are smooth, but 1mm ring end gap - need new ones, 1st over should do it. light scratching on piston sides, one 2.5mm x 1.5mm x .2mm height high spot in the scratches, but all that smoothed out with 600 grit. Scooter gearheads here in detroit looked at it and said it's fine. I decided not to post pics because of the high sensibilities already in this thread (which the last post continues).

The exhaust arrow and "SC" are clearly marked on the crown, so I didn't need further answers on that.

Thanks to whoever added the rectifier comment.

The bike is all original including paint (except cowls), hence my desire to keep it as close to that as possible. Battery stays. turn indicators, which were lost at some point in the past, will be re-added. I may try to work LED bulbs into that with some kind of resistor (?) to get the blinker to blink.

bottom end is very clean. don't anticipate replacing anything other than seals and cruciform. clutch isn't opened yet.

My comment was only to indicate that one requires a thick hide to hang around this Not So Modern Forum, A point I have learned the hard way over the last few years.

*like*

um. okay.

yeah.

i'd write a lengthy descriptive post here about how it all works and how you should go about it, but, yeah, you seem to have it all well in hand.

good luck.

-g

If going the LED route, instead of fitting load resistors, change the relay to an LED compatible one to make use of the power savings.
If you need help with the reg/rec, pm me.

I didn't know they had those. Will do, when I get to that part. Tx

C'mon, it ain't that rough...

You should. This preachy stuff is against the posting rules. Do I need to reference the posting guidelines put up by Jess? Ha.

your wasting yr time sfvsr in that time to post you could of rolled a joint smoked it tossed off looking at ugg boots online and made another cuppa

Shit. I was smoking one and wearing Ugg boots while I was typing it.