Primavera engine rebuild. COMPLETE.
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1964 GS160, 1966 90ss, 1976 Sprint Veloce
Joined: 08 Sep 2011
Posts: 340

Sun Aug 02, 2020 8:32 am quote
I picked up a 1973 Primavera engine for cheap, and started the teardown. This is corona lockdown boredom project #2. My Internet friend snagged it for me in San Francisco, and had it shipped (thanks Jasper!). It was possibly a police bike judging by other bits the seller had on hand. It's definitely been apart before. I haven't decided on stock or tuned. I'm also looking for a frame to put it in. Here are a few pics.

Freshly unboxed. Bit of corrosion from the marine environment.

Uh oh. Where's the breather? This can't be good.

What's this orange crap? Not rust. It looks like it was sprayed on deliberately.

Always good advice according to

Who wants to talk about the felt ring?

The top end is in really good shape. It appears someone filled it with gearbox oil before it sat. All nice and clean. The barrel looks freshly honed to me(crosshatched). What say ye?

Split. Now we see where the SF fog has leaked into the transmission via the missing breather.

Seals and crank bearings look good, but will probably be replaced.

Bottom end has issues. Rear axle bearing is toast.
Nylon lock nuts? Seriously?

Last edited by gmontag on Mon Sep 14, 2020 5:35 pm; edited 1 time in total
73 & 74 Rally, 76 ET3, 80 P200, 06 PX150, 61 Ser 2, 65 Silver Special, 86 & 96 Elite 80s, 2015 HD Road Glide Special, 2011 Ural Tourist
Joined: 18 Jan 2012
Posts: 3750
Location: Oceanside, CA
Sun Aug 02, 2020 8:43 am quote
Nice 4 speed motor find!

The copper spray is exactly that. Copper high temp gasket spray.

Definitely replace all the seals and donít skimp on high quality gaskets/sealer. Smallframes develop air leaks in so many weird places that I just go full overkill on the sealer now.
Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: 21 Oct 2005
Posts: 8030
Location: The state of insanity, SoCal
Sun Aug 02, 2020 2:34 pm quote
i wouldn't really sweat the nylocs tbh.

but after seeing what all you've got there i'd be doing a full comprehensive teardown and rebuild.

cool score though!

1964 GS160, 1966 90ss, 1976 Sprint Veloce
Joined: 08 Sep 2011
Posts: 340

Sun Aug 02, 2020 4:11 pm quote
Thanks. You are right. the nylocs aren't so bad. The stator and fan cover had a mix of incorrect fastener hardware, and I had to drill out a couple of bolts there.

How do you rate the condition of this shift dog?



1964 GS160, 1966 90ss, 1976 Sprint Veloce
Joined: 08 Sep 2011
Posts: 340

Tue Aug 11, 2020 5:36 pm quote
What do you make of this piston? 55.4? Is that 2nd oversize for VMA? It's a GOL piston if that makes any difference.


1964 GS160, 1966 90ss, 1976 Sprint Veloce
Joined: 08 Sep 2011
Posts: 340

Mon Sep 14, 2020 5:35 pm quote
I'm stuck inside because of all the wildfires, so might as well make some more smoke.

I threw together a two bit engine stand over the weekend and decided to try to fire her up. To my surprise, she turned over on the second kick. This is with no carb adjustments and just a bit of fuel.

Question: This engine will not stay in neutral. I am 99% sure the gears are in correctly, and I zip tied them during the rebuild to keep everything straight. It's like there's enough space for neutral, but the spring on the selector wants to push it in to 2nd or 1st. It's unstable in neutral if that makes sense. Is that normal for a smallframe engine on the stand?

To do:
Get a proper exhaust. That's a 90ss pipe which won't fit on a Primavera.

Carb and airfilter. That's an old 16/16 I had lying around and the filter bushings won't fit over the studs. Not sure what's up with that.

Hub. Someone replaced the studs on the hub and they have backed out. One was even smashing against the rear brake.


There's are 6" metal spikes holding the 4x4s in place, so it's not quite as flimsy as it looks.

P200 VNB Li125
Joined: 28 May 2008
Posts: 4434
Location: Hustletown, TX
Mon Sep 14, 2020 5:58 pm quote
1963 VBB2T
Joined: 07 Nov 2012
Posts: 2284

Mon Sep 14, 2020 7:45 pm quote
Motor looks great and nice simple setup for the stand.
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