OP
@technomama avatar
UTC

Enthusiast
Vespa et4 leadier 125, Vespa Lx 50 2t
Joined: UTC
Posts: 94
Location: Vilnius
 
Enthusiast
@technomama avatar
Vespa et4 leadier 125, Vespa Lx 50 2t
Joined: UTC
Posts: 94
Location: Vilnius
UTC quote
Engine overheating, I had to go desperate with sandpaper to grind off the aluminium oxyde buildup. Is it devastatingly wrong? I thought oxyde would be abrasive too, so in any case, I will need to splash it with kerosene anyway. While mounted on the engine, it wasn't possible to access all areas.
Forum member supplied image with no explanatory text
@rallygeek avatar
UTC

Hooked
Polaris Grey Rally 200, Blue Marine Primavera ET3, Coral Red 50 Special
Joined: UTC
Posts: 463
Location: Melbourne
 
Hooked
@rallygeek avatar
Polaris Grey Rally 200, Blue Marine Primavera ET3, Coral Red 50 Special
Joined: UTC
Posts: 463
Location: Melbourne
UTC quote
Is that really going to make that much difference to an overheating problem? I would have thought checking water pump or looking for head gasket leaks would be more important.
@znomit avatar
UTC

Veni, Vidi, Posti
LX190 Friday afternoon special, [s]Primavera[/s], S50, too many pushbikes
Joined: UTC
Posts: 10792
Location: Hermit Kingdom
 
Veni, Vidi, Posti
@znomit avatar
LX190 Friday afternoon special, [s]Primavera[/s], S50, too many pushbikes
Joined: UTC
Posts: 10792
Location: Hermit Kingdom
UTC quote
Rallygeek wrote:
I would have thought checking water pump or looking for head gasket leaks would be more important.
It's air cooled.

Check the fitting of the shroud and that the impeller is whole and there's no critters living in there. Otherwise how do you know it's overheating?
OP
@technomama avatar
UTC

Enthusiast
Vespa et4 leadier 125, Vespa Lx 50 2t
Joined: UTC
Posts: 94
Location: Vilnius
 
Enthusiast
@technomama avatar
Vespa et4 leadier 125, Vespa Lx 50 2t
Joined: UTC
Posts: 94
Location: Vilnius
UTC quote
I realize that it is overheating because it is nocking soon after start. Higher octane, (98 instead of 95) and extremely rich mixture helps a bit - I can ride 5 km but then it starts knoking heavily. I have found that krankshaft oil passage most likely is cloged and oil doesnt get through connecting rod bearing freely, although bearing itself looks ok. I can barely push carb cleaner through it and flush oil doesnt' go through it at all. So I'm fixing that, and yes - I read now that aluminum oxyde is quite termal conductive. Well it will look diedier now, just thinking how to get rid of these corundum and possible sandpaper particles. Cowling is fine and fan blades are intact. Head gasket - which one? The metal one that goes between cylinder and head, it is new, I put it last year. The rubber one for valve cover is leaking a bit, but I didn't realized it may be overheating problem? Surely I'll fix it this time. Thank you for your replays.

p.s. oil preasure was ok before oil flush and engine dissasembly. Oil pump clearances are well within limits too and the rest of oil passages are ok. Yet I've found thin long metal shavings aside plain bearing of the crankshaft, on the flywheel side. Bearing itself shows streaks of brass. Fiew small brass particles were in coarse oil filter too. Transmission side bearings are ok, no visible damage. Inside cylinder there are marks that I red maybe water damage (image) smooth to touch, expet one spec that can be felt recess. I got this engine last year as engine swap, I have some history of it but it's owners riding style.
Forum member supplied image with no explanatory text
DoubleGood Design banner

Modern Vespa is the premier site for modern Vespa and Piaggio scooters. Vespa GTS300, GTS250, GTV, GT200, LX150, LXS, ET4, ET2, MP3, Fuoco, Elettrica and more.

Buy Me A Coffee
 

Shop on Amazon with Modern Vespa

Modern Vespa is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com


All Content Copyright 2005-2025 by Modern Vespa.
All Rights Reserved.


[ Time: 0.0154s ][ Queries: 4 (0.0027s) ][ live ][ 323 ][ ThingOne ]