Spare Engine Project, PV125

[boreham]

So, a bit bored and looking for a small project, I came across the engine kit DaveT had up for sale, met up yesterday, great to put faces to names!
The plan is to put together a nice spare engine for the scoot, I had a good look through everything yesterday and have the basis of a nice 125.
The cases are PK and have at some point had a small end failure and wrecked the pad, so the plan is a reedvalve conversion, 24phbl and a gentle tune on the barrel.

The first job was to get the old inlet studs out, they well totally seized, usual with steel in alloy, tried heat (lots) then a stud extractor which stripped, finally welded a nut on and managed to get 2, the 3rd just sheared, finally welded on a 10mm nut and it cracked which was a relief.
So this morning Started on shaping the inlet and match the reed.




All matched, now to polish nice and smooth to flow correctly, also re tapped all the threads and blended the transfer ports with a gentle shaping, it’s a standard engine so just want to make it fit nice and accurately



Cuppa and start on the bearings !

[boreham]

Gearbox built, all the parts supplied fitted perfectly, just had to have a sort through the spares boxes for a thinner shim, finally got to 0.06mm so spins lovely!
I found a 24/61 primary at Pedparts for £30 on offer which was a bargain.


Bearings all in, nice and simple with the right tools, just missing a crank woodruff so feet up for today, need a few small bits and a couple of circlip, plus a 6204 rear wheel bearing, then fun with the barrel.

[davet]

Looks so much healthier on your towel than it did on mine Nice work.

[tzsteve]

Problem is once the engine is built you will then have a change of plan
And then you will need space for the extra scoot

The reed block looks nice

[boreham]

Aug 6, 2020 11:35:26 GMT tzsteve said:

Problem is once the engine is built you will then have a change of plan
And then you will need space for the extra scoot

The reed block looks nice

Already thinking of a frame to pop it in, too good to leave on a bench 

[tzsteve]

Been there done it myself,
You leave two scoots alone for a few months only to find they have been breeding while your back was turned
I ended up with;
An ET3,
V range 125 water cooled,
PK 125
And a Suzukii GT250

But in those days insurance was a little simpler and parts were more readily available

[boreham]

Totally agree, bought an RD350 in 1986 after I passed my test, paid £870 for it from a main dealer, times have changed, not much change out of £5K now, insurance was about £40 🤣

[boreham]

So spent the afternoon building up the engine, postman came so a few goodies I needed.


Gear linkage and kickstart in, it was too bloody warm to stand outside, lots of tea breaks !


Gearbox done, all went together nicely


New gaskets for the reed block, then put the casings together, the faces all looked nice and straight but used a smear of loctite 510, took a bit of wiggling to get it all to slide together, was missing a D bolt which was a pain!
Next the clutch, it came with a 4 plate clutch and updated spring but just wouldn’t go in so have to drop it apart and build in situ, it’s a Ferodo basket so may be a little deeper than a Piaggio one.



Next job the barrel, the engine had come with a complete new 125 kit, however searching in the boxes of bits for a set of studs I came across a barrel in wax paper, definitely a smallie but also not standard as it’s 57mm, has 3 boost ports, it’s cast, absolutely no idea where it’s from or when I got it!!
Will put up a few picks vs the standard to see if anyone can spot the barrel!

[tzsteve]

Rd 350's are a little scarce now,
A lot where the first quick bike after passing the bike test so they soon got crashed by inexperienced riders,
A lot acted like a magnet for the bike thieves, so they got pranged or stripped for parts,

Result not many left now

The LC350 suffered the same sort of problems.

My one the TZR250 was never as popular,
list price was about £4000 not cheap as it was the fastest 250 at the time ( 120 mph ) not bad in 1988
the 125 learner laws were just starting to have the effect
Of getting a lot of new riders leaving the 250 bikes alone and going straght from a 125 to a 500 or 750

Mine now is worth about £1500 to £2000 even painted in Kawasaki green ( more easily seen than the Yamaha blue )

[tzsteve]

That reed block looks ok
How much ?

[boreham]

The Malossi one (when I read up on them) has slightly larger cross section reeds than the more common Polini kit, this came with the casings I got of DaveT, but SCK have it for £118 in stock at the minute.

[boreham]

Mystery barrel, as above its 57mm so 130cc, any ideas

[boreham]

Picked up a great frame from DaveT, a long stored frame which has had some panels replaced but apart from surface rust is very good.
The plan, as the frames so good is a nice standard PV125 using this engine.
The frame VMA2T shows it as an early 1977 Primavera, no docs but clear frame numbers so should be ok.

[boreham]

[tzsteve]

the frame looks nice and straight

I bought 5 lts of phosphoric acid for about £15 from fleabay,
does a great job of removing rust just make sure to remove all traces as it can affect any paint

or are you going the sand blast way?

[boreham]

I think the frame had been blasted at some point and then not coated, the outer frame is all light surface so may come away with a light sand, the underside may need a blast but tempted to look at the acid or a local media blast as a bit more gentle.

[boreham]

So engine finished today, pressure tested, all good, drop of fuel in the carb and started 3rd kick, sounds lovely ticking over but compared to the M1R is almost silent.
Exhaust is the BGM Sport Banana, initial carb settings on the 24mm phbl are 50 pilot, AQ264 atomiser, D22 needle and dropped in a 100 main for now, timing static at 17 degrees.

[tzsteve]

blasting has the advantages of
little effort
and it leaves no residue
but it must be primed the next day


don't clean engines look nice

[boreham]

So 3 days of sanding and we are nice and flat, seam sealed all the joints and got the doors fitting all square, drilled all the footboard holes and ready for paint.




Started to source a few parts, I thought I would try and get as many genuine parts as I could, will be nice to have a standard quality scoot and the mental one is the garage when needed.
I managed to find NOS forks, hub, front pivot, petrol tank.
Had to settle for a repro headset which I found at Tonazzo in Italy which I had never used, it came in 2 days !!




It goes in on Thursday but still can’t decide on the colour, definitely want something very retro 70’s, I am swayed with Orange or Green and thinking of the Rosso Canyon 921 ?

[boreham]

Option 2 is the green, hmmmmmmm