Modern Vespa

I decided to open up the engine on my 2006 LX150 (13,500 miles). There was nothing obviously wrong with it to require this. There were some minor issues (oil in airbox, oil on cylinder, harder starts). But if I'm honest, really I just wanted to do this as a winter project and to show this bike some attention. "There are many like it, but this one is mine."

I asked about splitting the cases in another thread, and Greasy wisely talked me out of it. So I'm just looking at the top end.

I found:
1) intake valve tight (0.1mm gauge fit if pushed, but was very snug)
2) one of the cylinder studs was loose (unscrewed by hand - will Loctite and reinstall)
3) gouge in the upper cylinder surface (doesn't go all the way to cylinder, but deep enough to catch a nail. This was there before. I'm not sure what to think of this?)

And I verified:
1) insides are generally very clean
2) no metal sparkle or sludge in oil sump
3) valves not leaking (held carb cleaner for 30 min without drip)
4) cylinder has good cross-hatching and no gouges

I posted some photos below. Anything look obviously wrong? Is this level of carbon buildup normal for an engine of this vintage?

In particular, what should I make of that cylinder gouge? Presumably I've been running with that for years, so maybe a non-issue. But then again, it might make a good excuse to buy a big bore kit.

If I'm looking at the same part, I'm not sure I see the gouge in the photos before the cylinder was cleaned up. If it was there, then it passed QC and ran for 13500 miles before you decided to take it apart, and you can use it again.

You want a big bore kit I got a used you could buy. The gouge is not anything the gasket won't take care of. I would not worry about it. The 190 kit is a nice improvement in power if your looking to go that way.

It's pretty dirty, so easy to miss, but the cylinder "before" picture still has the head gasket in place and covering the gouge. Thanks for advice on part being ok!

Slowpoke, if Berto does not want the big bore kit, I may be interested.
Berto, it all looks good, maybe just check the end gap on the rings?

How are the cams looking?

I think they look alright. Some wear marks, but no scratches, gouges, burn colouration, etc.

Can someone please verify that little spring washer goes between the two rocker arms (as opposed to on the end)? In my 4th picture below. It fell out before I noticed where it came from.

I checked the shop manual and parts diagram, but they don't seem to match up exactly with the cam setup here. At least the washer isn't obvious to me

Ugh. The good news is that I found a parts diagram for the 2V version of the leader engine. The bad news is that it doesn't show the spring washer location either!

Is someone able to please confirm the spring washer goes between the two rocker arms, as shown in my photo above?

Let me check when I get home, but I'm pretty sure it goes between the rocker arms.

Berto, you do know we have our own manuals site? https://manuals.wotmeworry.org.uk/Vespa/LX150/

I have to agree that that washer isn't shown at all.

Pic from the camshaft which I kept bagged as an assembly when I pulled it out of the project head I bought.

Also, pic from eBay of a used head, you can barely see the washer between the rocker arms.

This is fantastic! Thanks for taking the time!

Yes, I should have mentioned I checked there too! It mentions the washer and gives a diagram that kind of shows it, but still left a little ambiguity.

I'm taking my time here, since it is a "fun" hobby project!

I ran the cylinder and (disassembled) head through an ultrasonic cleaner, which removed 10+ years of thick grime - very satisfying!

I inspected and lapped the valves, and installed new valve stem seals.

Inspected the decompression mechanism - all good.

Replaced a couple of seized engine dowels, and re-torqued the engine stud that had come loose. Fresh gaskets all around. Set the timing and buttoned it up!

I also put in a new transmission belt while in here.

This thread was interesting for a budget approach to replacing that seal plate. But I'm going to stick with greasy's advice and leave well enough alone.

I'm going to replace the steering bearings while the engine is out (they started squeaking last season). This way I can more easily lift it onto a table, given I do not have a proper lift

I did the steering bearings on my 500ie a little over a year ago. Good project as long as you have the right tools - threaded rod, high quality nuts, bearing presser plates of the correct sizes, freeze spray.

https://www.apriliaforum.com/forums/showthread.php?333976-Beo-500-ie-Steering-Head-Bearings/page2

if doing just the bearings it's not that bad. but races and bearings is a bit of an undertaking.