Scooterotica

Good evening Gentlemen, a quick question for those with more knowledge than me.
I don't have access to a dyno, but would like to know what power/torque my engine is putting out approximately.
I'm 12 st 11lb in my birthday suit and my scooter is a full bodied series 3 lambretta. It'll do a true 85mph with me in a normal seated position (not prone). Any ideas as to what my engine is making?

A Honda CB250N had a top speed of 83mph and made 27bhp and made 14.7 lb ft of torque. So I reckon, with a complete absence any other information, that yours is close to that.

Any help?

What engine is it?

Carb, kit, crank, exhaust?


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Your weight has very little to do with your top speed. It's primarily determined by power and aerodynamics.

Weight, mass, inertia (all sort of the same thing) have a big influence on how you get there. F=ma.

Weight influences how much power is wasted as heat in wheel bearings and rolling friction from tyres on tarmac but not a lot else.

Having said that, fat lads tend to make bigger sails.

drunkmunkey6969 wrote:What engine is it?

Carb, kit, crank, exhaust?


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It's a Rapido cylinder that I've played with, converted to reed valve (MB shorty, 6 petal), boost port, windows cut in piston (forged wossner 70mm with crown height for 115mm rod), Avanti head, 60/115 balanced crank, transfer enlarged and matched at casing/ cylinder (no welding so not too big), inlet and exhaust ports enlarged/flowed to manifolds, indian ignition with Kytronic advance/retard unit, TSR evo exhaust, 30mm PWK carb with breath sweet remote filter.
Think that covers it

A well-built engine, of that spec, if ported accordingly should turn out 24-28bhp no problem. Although not revy, that particular pipe has a good lump of torque to it, so should pull decent gearing.

drunkmunkey6969 wrote:A well-built engine, of that spec, if ported accordingly should turn out 24-28bhp no problem. Although not revy, that particular pipe has a good lump of torque to it, so should pull decent gearing.

Bloody hell! I was nearly right!

I say you take it here and we have sweep stake...

http://www.fullthrottlepowersports.com.au/pages/dyno

servetakid wrote:I say you take it here and we have sweep stake...

http://www.fullthrottlepowersports.com.au/pages/dyno

That would be interesting, wonder if they let smokey old two strokes on their dyno?

Thanks for all the replies, hopefully I'm in the high twenties then. With the TSR evo pipe it certainly has no trouble pulling the 4.8 gearing I've got it set up on at the moment!