Trouble with freshly rebuilt motor vbb
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Member
Joined: 21 Nov 2017
Posts: 24

Tue Jan 08, 2019 12:50 pm quote
Hello beautiful folks! So I have just recently rebuilt the motor, fresh seals, gaskets and everything that needed some love. Upon my first outing she ran quite all right; but then all of a sudden the motor shut off completely, which I thought it had seized but thankfully after a few minutes I cranked her back over and all was well, until it happened again a few minutes later. Fast forward to a few weeks later I'm attempting to turn it over, but she won't stay on. I can get it to start with starting fluid, which leads me to believe that there is an electrical issue preventing it from staying on. Would the stator or the coil be my next place to investigate? How does one go about testing a stator plate. Also the stator was the only thing I didn't replace. Thank you so very much for reading and please give any sort of advice that I should look for.
Molto Verboso
05 Stella, '62 VBB, 76 Sprint V, 63 GL
Joined: 16 Jun 2011
Posts: 1949
Location: Chicago. Well, Evanston, but that's almost Chicago
Tue Jan 08, 2019 3:45 pm quote
Sadly, it sounds like you've probably soft-siezed it to death.

Have you pulled the head to inspect the bore?

Running with starting fluid but not off gas indicates a fuel problem.

If it's electrical, you can test that by checking for spark grounding the plug to the motor, though.

Also, did you pressure test the motor after the rebuild to ensure no air leaks?

Share some pictures. We like pictures, and they can be helpful.

and welcome!
Member
Joined: 21 Nov 2017
Posts: 24

Wed Jan 09, 2019 12:11 pm quote
Thanks for the warm hello! What does a soft seize look like I've never hears of such a thing. When it cut out it just flat out died and my wheel locked as if seized then when I pulled the clutch; I was about to roll safely to the shoulder where I waited and she turned back over. I'll check the spark later but ive never pressure tested a 2 stroke engine and actually this was one of the main reasons I even rebuilt the motor; it had a run away idle that was pulling air in from somewhere. How does one pressure test these motors?

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Hooked
Vespa P200, Primavera 130, VNA200, Italjet Pack-a-Way Moped, Ciao etc
Joined: 24 Oct 2014
Posts: 319
Location: Humboldt County, California
Wed Jan 09, 2019 2:27 pm quote
Oh dear....
Hooked
68sprint,65super,64Allstate,55 Allstate
Joined: 20 Jul 2017
Posts: 241
Location: Central california
Wed Jan 09, 2019 3:30 pm quote
Van engine
Oh dear is correct....I think you need to find someone that can help you. It actually sounds as if you might have some serious issues. That is not how the wiring should look. I see you have California plates on the scooter....there are some good scooter shops in Ca. All depends on where you live in Ca. Scott
Ossessionato
2 matching N.Z. '69 VBC Super, 177cc Racer, VespaCross Bodge, Puch SRA150, Piaggio Zip 100! & others
Joined: 26 May 2013
Posts: 3733
Location: Millbin, Ostrayleea, mate
Wed Jan 09, 2019 4:57 pm quote
1. This is a great description of a "soft seize"
What does a soft seize look like I've never hears of such a thing. When it cut out it just flat out died and my wheel locked as if seized then when I pulled the clutch; I was about to roll safely to the shoulder where I waited and she turned back over.

2. Where is the rest of the engine?
Ie fan cover & barrel shroud... they are the things that keep the engine cool

3. Try the "search" function

4. I won't even mention the wiring, mine is far more complicated

5. What is the origin of the scoot (we already have a fair idea.
This may assist with the most common causes.
Bodgespotting
Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: 21 Oct 2005
Posts: 7207
Location: The state of insanity, SoCal
Wed Jan 09, 2019 6:57 pm quote
seeing the pictures, this does not bode well...

however, not all hope is lost. you might get lucky.

if you were running it w/o the fan cover and shroud that would be the cause of your seize. put that stuff on and run it and see. if not, well follow the diagnostic tree.

check for spark first. then check for fuel flow-- both at the line and from the carb into the inlet. then check compression. you may want to pull the head and inspect the barrel as well. either way report back on the basics first.

once the basics are covered then you go deeper: checking the coil, points/timing, ignition system, fuel delivery, leak down test, etx.

at best you've got a fuel delivery/jetting issue, from there you might be chasing your ass on a wiring/timing/ignition issue.

sometimes with these bikes once you open the motor all the magic gets let out and they never go back to running again.

good luck!

-g
Ossessionato
LXV 150 Midnight Blue (SOLD)
Joined: 06 Dec 2010
Posts: 2434
Location: Bangkok
Wed Jan 09, 2019 7:30 pm quote
Re: Van engine
Sjanuary wrote:
That is not how the wiring should look.
As long as the wires are correctly terminated everything else is cosmetic. Couple of tie-wraps will sort that out.

I'm going with overheating as you are not running with the fan shroud etc..
Hooked
68sprint,65super,64Allstate,55 Allstate
Joined: 20 Jul 2017
Posts: 241
Location: Central california
Wed Jan 09, 2019 8:37 pm quote
Van motor
If your running an air cooled engine with no fan shroud and it has been oveheated as you say: hence the soft seizes than you need some outside help. My guess is you donít understand the mechanical issues with an internal combustion engine. It is all good, I just think you need some outside help to get your problems sorted out. The forum here is a great place to be, for info and advice, but you are going to need a certain amount of knowledge in regards to mechanics. Scott
Member
Joined: 21 Nov 2017
Posts: 24

Wed Jan 09, 2019 11:10 pm quote
Hey folks. I definitely should have mentioned that the fan shroud and cover is all for test riding the bike. My question would be how long of a ride would it take for a motor to get hot enough to seize. The test ride in which this occurred, could not have been more than a 10-minute ride. I definitely have a more than through understanding of engines, just take a look at the air cooled vehicle right behind it which I have completely restored top to bottom and rebuild the motor. I'll try an tackle some of the mentioned suggestions. Thanks
Addicted
Vespa lxv 125 vie dell moda Chianti
Joined: 28 Aug 2012
Posts: 738
Location: Cheshire
Wed Jan 09, 2019 11:16 pm quote
10 mins too long cylinder would be overheating befor 5 mins without shround and cover,
Ossessionato
LXV 150 Midnight Blue (SOLD)
Joined: 06 Dec 2010
Posts: 2434
Location: Bangkok
Wed Jan 09, 2019 11:32 pm quote
areabaylove wrote:
, just take a look at the air cooled vehicle right behind it which I have completely restored top to bottom and rebuild the motor. I'll try an tackle some of the mentioned suggestions. Thanks
Have you taken it for a drive with no fan belt?
Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: 21 Oct 2005
Posts: 7207
Location: The state of insanity, SoCal
Thu Jan 10, 2019 12:44 am quote
areabaylove wrote:
Hey folks. I definitely should have mentioned that the fan shroud and cover is all for test riding the bike.
okay, that's good.
Quote:
My question would be how long of a ride would it take for a motor to get hot enough to seize. The test ride in which this occurred, could not have been more than a 10-minute ride.
easily that. probably less than 5min to be honest though.
Quote:
air cooled vehicle right behind it
well... technically... that's oil cooled, not air cooled. but it's all good, you have mechanical know how which is a huge plus in this situation.

but yeah man, i'd check the criticals first before throwing parts at an unknown problem. all of the mentioned things are quick and easy to do and should turn up a culprit. if not, then at least you know that it's time to dig in and spend some time and money.

-g
Member
Joined: 21 Nov 2017
Posts: 24

Mon Feb 04, 2019 9:40 am quote
Hello again folks!!! So i spent the last few days trying to fine tune everything and make sense of what was wrong. She runs beautifully when she does finally turn over. What I'm dealing with now is she takes way to many kicks to finally get it going and should I accidentally stall or I kill it, I can't seem to get her started again for the life of me until much later or the next day. I've got great compression, good spark, i smell fuel what I'm I missing? The only other thing I haven't really gone through was the stator itself. Thanks folks!!

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