£500 Engine Build

[NorthernJordan]

I'm looking for some inspiration here. I've got a ratty special that I just want to bomb about on and be able to hit a really 60mph for rallying.

Doing it on a budget is important and want to keep things cheap. So looking for set up suggestions.

I have a few good parts kicking around:
Ron moss clubman.
Li150 gearbox.
Af flywheel.
Original sprockets.

Need crank, ignition, top end (original is knackered getting it off) and carb.

Thoughts please?

[missing lynx]

Small block or big?

[NorthernJordan]

Small block, 150 special engine

[rossclark]

Tameni Gp crank and and a Scootronics stator will set you back about £200

For small block you might be able to find a deal on an RT - with the right gearing it'll do 60 bit that'd push your budget.

[missing lynx]

I'd look at the new scootopia barrel kit with their 22mm carb a re worked sil stator and a good quality crank you will obviously need new bearings and a descent clutch

[vegansydney]

Piston: TS185ER (~£35)
Rebore original cylinder and reprofile head (~varies)
Carb of choice: Mikuni TM24, PHBL or SH2/22 (~£100)
Manifold: MB flange type, Scootopia or SIL GP150 (~£40)
Clutch: Surflex B with GT or MB uprated springs (~£30)

I just pulled my Silver Special out of storage (where it's been sitting for the last 8 years) with a similar set up, and have been riding it all week and absolutely love it.

[Warkton Tornado No.1]

I'm looking for some inspiration here. I've got a ratty special that I just want to bomb about on and be able to hit a really 60mph for rallying.

Doing it on a budget is important and want to keep things cheap. So looking for set up suggestions.

I have a few good parts kicking around:
Ron moss clubman.
Li150 gearbox.
Af flywheel.
Original sprockets.

Need crank, ignition, top end (original is knackered getting it off) and carb.

Thoughts please?

Second hand Indian (SIL) 200 crankshaft re-rodded to suit piston choice. Forget about trying to maintain or increase primary compression if you must buy a new crank. If you find that difficult to believe, other, better two stroke fans than the likes of me have proven 'HPC' to be detrimental. Just by fitting packers & a longer rod achieved power increases.

OEM Innocenti SX/GP 150 barrel or TV175.

OEM or good pattern motorcycle piston to suit chosen bore. (There are 65 mm pistons available for power sports that have only one ring that can be modified with an additional ring. That said, the TS185 piston is a good choice but better (IMO) with a long rod fitted)

Optimising of all ports.

Re-worked CDC manifold to suit.

Koso, OKO or Polini PWK carburettor or Chinese copy blueprinted in conjunction with adequately sized air filtration. Selected because they are cheap & easy to set up & do not hot flood like antique modified four stroke PHBL's when filtered. Unless you think drilling holes in the bellows is a terrific idea......

If you are after reliability, sell on the flywheel & revert to contact breakers with 12 volt conversion & a modified 'J'/Luna flywheel.

You should come in well under your budget & I would expect to see mid 60's or so, as Ron's exhaust could work well with no heat build-up issues. I am unaware of the 'U' pipe size but that could be an issue if too big. 42 mm absolute maximum I would conjecture if staying @ about 150 cc........

[Andyf]

I just pulled my Silver Special out of storage (where it's been sitting for the last 8 years) with a similar set up, and have been riding it all week and absolutely love it.

smiling big at this. and insane with jealousy.

[vegansydney]

...the TS185 piston is a good choice but better (IMO) with a long rod fitted)

I'm running SIL webs with an RD400 on one of my TS185ER set ups and a TV rod on my other, and completely agree.

smiling big at this. and insane with jealousy.

Thanks! I've been riding it to the beach everyday

[Warkton Tornado No.1]

I regret selling a GP150 that I owned in the mid 70's. I bought it purely as temporary transport whilst my first 200 was in dry dock, so did virtually nothing to it, apart from fitting a standard exhaust that had been de-baffled along with 200 forks & reverse pull disc.

It was absolutely reliable, would run day in, day out, fuelled faultlessly @ 2% Filtrate with it's SH2/22 on standard settings & very economical. Because the exhaust allowed an amount of over-run, it would keep up with most 200's of the time, & even the unloved gearbox wasn't an issue.

Lambrettas come in for a lot of stick compared to Vespa, but MHO is that most of them have been messed with by previous owners believing their amateur efforts can work wonders. Left mostly as intended, with good fuel/oil & not ridiculously retarded from standard, they can be a pleasure. Trouble is, we can so easily justify to ourselves " I'll have one like that, another with a Quattrini kit, another with a torquey Kawasaki H2 piston kitted engine of around 240........"

[Nigel. S]

^ I stupidly destroyed my Casa 185 last year, entirely my fault. The next weekend coming was a event I couldn't miss. All I had lying around was the bits and bobs to rebuild as a GP150. So front sprocket back to standard, 22mm carb, points (which it always had).
Rode it to the event and you're correct, it was a real pleasure to ride. No rocket ship of course, but I enjoyed riding less lazily which the torquey casa made me do.

[NorthernJordan]

I think the plan is a 150 special/GP barrel bored to 175 with a decent piston. 30mm carb and ron moss clubman. Hopefully I'm in the process of obtaining a GP.
New bearings, seals and clutch plates.

I think I has some spare electronic parts kicking about so will see where that takes me.

If I'm frugal and some of the parts offered come through I should hopefully get the whole scooter on the road for about £500.

[missing lynx]

A 30mm carb is overkill I would go for a 26mm maximum