Having a pub "discussion" about top speed

Anything related to Lambrettas... ask tech questions, post helpful info, or just read and learn.
onthelam
registered user
Posts: 162
Joined: Thu Feb 26, 2015 3:54 am
Main scooter: not yet
Location: Bangkok
Contact:

Fri Mar 30, 2018 5:06 am

What is the top speed of a Lammy 200 in standard form. Say a GP 200.

User avatar
garry inglis
registered user
Posts: 1249
Joined: Tue Jul 21, 2015 8:04 pm
ebay user ID: garry52uk
Main scooter: ts1 230 and rb200
Location: darlington
Contact:

Fri Mar 30, 2018 6:01 am

68mph😎

onthelam
registered user
Posts: 162
Joined: Thu Feb 26, 2015 3:54 am
Main scooter: not yet
Location: Bangkok
Contact:

Fri Mar 30, 2018 6:35 am

:idea: That is what the bible says...

If i put all the bible numbers into a spread sheet they all come out more of less at the same drag coefficient. Except SIL 200 which I assume is the exception that proves the rule. :lol: And the SX150 which I assume is geared low.

:?: So if a Lambretta with =/-12hp can do 68 mph why can't a Vespa with 12hp do the same

I am still interested in other claims for a stock 200.

mick1
registered user
Posts: 1539
Joined: Sun Dec 04, 2011 7:43 pm
ebay user ID: saxonleaf
Main scooter: Li Avanti 225
Location: York
Contact:

Fri Mar 30, 2018 7:49 am

The 12hp on two different engines can produce two different top speeds due to where the peak 12hp is achieved. The speeds (and where maximum power is achieved) are also relevant to the gearing and the exhaust.

A good example is a tractor which has loads of hp but doesn't achieve the same speeds as a small car.

I had a new SIL engine with their own big bore exhaust. Without tinkering it would only do 63mph (GPS).

onthelam
registered user
Posts: 162
Joined: Thu Feb 26, 2015 3:54 am
Main scooter: not yet
Location: Bangkok
Contact:

Fri Mar 30, 2018 8:03 am

Yes gearing and whether the engine is allowed to achieve its potential and aerodynamics.

Ok I'll add 63 to the list

Lambretta Sash
registered user
Posts: 166
Joined: Tue Oct 04, 2011 8:10 pm
Main scooter: Lambretta TV 230
Location: Lowestoft
Contact:

Fri Mar 30, 2018 10:27 am

Ive got a few logged from taking road dyno to events, my m8's sx200 with the addition of 22mm carb ran 51mph 8.5 hp rear wheel.
The sil gp200 was 12hp measured at flywheel.

storkfoot
registered user
Posts: 1283
Joined: Thu Jan 08, 2009 12:08 am
Main scooter: '70 GP150 [TS1 225]
Location: Merseyside
Contact:

Fri Mar 30, 2018 11:25 am

A few years back in Scootering, Sticky rode a standard electronic GP200 against Al Terry on a standard Rally 200. If I recall correctly, the Rally 200 edged it, speed wise, maybe even acceleration wise.

Adam_Winstone
registered user
Posts: 1769
Joined: Tue Jan 31, 2012 8:54 pm
Main scooter: Lambretta GP
Contact:

Fri Mar 30, 2018 11:40 am

I've had less than 60mph out of a factory 1980 home market Jet200 that was still fitted with a VERY restrictive Spanish version of the SIII exhaust (restricted by design and running very small jets to give excellent fuel economy) and high 60s on decent Italian models. Some of this will come down to whether you mean 'standard' being 'as it left the factory' or 'untuned but best configured for top speed'? By this I am bringing into the debate the issue of having a bike dynoed, etc.

Adam

Lamaddict
registered user
Posts: 1022
Joined: Wed Jan 07, 2009 8:35 pm
Contact:

Fri Mar 30, 2018 3:55 pm

My standard TV175, apart from an electronic ignition, will do over 60mph GPS speed and will happily sit in the late 50’s early 60’s all day long.
I ran a totally standard DL200 Electronic, top speed was mid 60’s but seemed too revy to keep it up all day. Now sold it and I’m more into the low revs for top speed.
I’ve had scoots up into the 80’s for a top speed but happier doing that speed on a motorbike 😎

Adam_Winstone
registered user
Posts: 1769
Joined: Tue Jan 31, 2012 8:54 pm
Main scooter: Lambretta GP
Contact:

Fri Mar 30, 2018 4:25 pm

^... TV's got a lot going for it and when you consider that it is basically an SX200 with 4mm dia. less bore, it isn't surprising that there's not much in it. Same carb, same gearing, same exhaust, similar porting, same ignition timing... all very similar, other than the compression height and rod length, which the TV175 betters anyway.

One of the things that I do find interesting is the configuration issues of the different factory specs, which tailors the performance to the customer requirement of market, i.e. less top but better economy in the Jet example mentioned, or the SIL IV spec for export market (UK driven and aimed at top end).

Adam

PS - As a pub discussion, I should point out that my Lambretta speedo has often been in the 80s when crossing the 1/4 mark at Santa Pod... yet the ticket was is the 60s!

Post Reply Previous topicNext topic
  • Information
  • Who is online

    Users browsing this forum: No registered users and 13 guests