SX/GP150 Barrel Identification

[Kev Fox]

Got the urge for a standardish 150 and trying to identify various barrels that I have. Ideally want a SX/GP150 barrel. Looking in Stickys book my interpretation is,
1) No slots in Spigot = Li150
2) 2 half moon cutouts in top fin = 150 Pacemaker
3) 2 slots in spigot = SX/GP150

Going by this info i have 2 barrels with just slots in spigot, one having 20mm inlet manifold the other a 22mm inlet manifold. Stickys book leads me to believe they are SX150 and GP150 respectively. What I also have is a barrel with both, 2 half moon cutouts in top fin & 2 slots in spigot. Of the 3 barrels I have described can anyone please advise on what they are?

[ToBoldlyGo]

I'm not sure I would use the slots in the spigot as a means of identification, because I'm sure there are variations according to who cast them. The two notches in the top fin would seem to be a reliable indication though. It's got to be from a Special, or GP. Although, it may be that there are slight differences in the porting between Special and GP. Somebody like Adam Winstone would be your man.

[Adam_Winstone]

Italian SX150 and GP barrels will both have the same markings, in the same way that Italian SX200 and GP200 cylinders have same part number and markings.

As far as the 150s go, they will have both the semi-circle notches out of the top fin plus the slots across the spigot (top and bottom). They would also both have the same size/shape inlet port, which is lozenge shaped and smaller than the more rounded Pacemaker or TV175 shape inlet (at face). NB: Yes, that's right that the TV175 has a bigger inlet port than the GP150, even though it has a smaller carb.

They should both have a number stub off the side of the inlet manifold area, and would have a + 0 or - stamped into the head gasket face.

Look for these features and feel free to post photos of what you have.

Adam

[Kev Fox]

Thanks for the reply Adam. This barrel shows slots in spigot and semi circle notches in top fin so you would believe this to be an SX150 OR GP150 barrel.

[Adam_Winstone]

Yes it has both slots and notches, which would suggest SX/GP150 but I'd like to see a photo of the inlet manifold area as I cannot obviously see the number stub that all Innocenti Series 3 cylinders should have. Combined with the blackening that is still visible on the fins, my immediate thought is that this could be a SIL barrel or aftermarket item, in which case you could rely on the the porting to be a mile out from the original Innocenti spec.

If you can take more photos from different angles (from top, from bottom, from side of inlet and inlet area with manifold removed then I can tell you more.

Adam

[Adam_Winstone]

Good timing. If you're on FaceBook there is a new post showing an original SX150 barrel for sale, which clearly shows all of the features that I mentioned previously...

I can't share the link but you can look for it under: Brian Jenkins listed this in Lambretta Scooters, parts for sale and wanted

The photos clearly show what you should be looking for.

Adam

[Kev Fox]

Found that Barrel for sale thanks for the pointer. The barrels I have are at a friends workshop so will take a better look tomorrow and take some photos. Thanks Adam.

[Adam_Winstone]

Hi Kev,

Good that you've seen the other barrel for sale as, along with my comments, should provide you with all you need to compare yours with.

Adam