LCGB Forums

I'm rebuilding my SX200 which has been in bits for 40+ years. I notice that the airbox has been drilled with numerous 10mm holes in the body. Does this actually help with engine breathing, or was it a fad? The air scoop baffle has also been removed. It still sports the air filter. The carb is a SH2/22 with standard jettying. Should I leave the airbox as is, or replace it with a new one?

No the Drilling allows more air into the system, not usually done for a standard scooter but more if an engine upgrade / larger carb has been added , your call re using it depends what engine you are running as to whether you need it drilled .

Toddy wrote:No the Drilling allows more air into the system, not usually done for a standard scooter but more if an engine upgrade / larger carb has been added , your call re using it depends what engine you are running as to whether you need it drilled .

As it has been so long since I ran the Scooter, I'm having difficulty in remembering just what I did to it. It did have a rebore to 225cc, I don't remember getting the SH2/22 carb, but I still have the SH1/20, so who knows what I was thinking back then. I know I was looking for speed as I ran to scoot with minimal panelling and a small alloy front mudguard. I'm thinking more conservative now, with regards to speed, my good lady not too keen on dashing about. I was thinking of fitting a AF Rayspeed Classic Rapido kit, possibly 225, as this is described for the larger gentleman or riding 2 up. Maybe I should keep the air box as it is, but AF suggests different carb set up! Are my secondhand carbs of any value?

Yes, both carbs will have a good value for those wanting to keep originality.

you can still run your airbox & carb as is with your 225 or your Rapido upgrade, but keep an eye on your plug colour, as you'd probably need to keep an keen eye on your pilot & main jets

hullygully wrote:you can still run your airbox & carb as is with your 225 or your Rapido upgrade, but keep an eye on your plug colour, as you'd probably need to keep an keen eye on your pilot & main jets

With modern fuels, would this mean increasing the size of the pilot and main jets? Would I also need a thicker head gasket to lower compression?

jets wise - alter to suit your engine, carb, exhaust, kit, check plug colour thru' the rev ranges a must!!!!!
compression ratio etc... I know AF's do 2 x types of heads for 225's, higher & slightly lower compression ratio's, plus you'll need to check the piston/head squish clearance of 1.1mm -1.5mm, another must with todays fuels!!!!

hullygully wrote:jets wise - alter to suit your engine, carb, exhaust, kit, check plug colour thru' the rev ranges a must!!!!!
compression ratio etc... I know AF's do 2 x types of heads for 225's, higher & slightly lower compression ratio's, plus you'll need to check the piston/head squish clearance of 1.1mm -1.5mm, another must with todays fuels!!!!

Not a walk in the park then!

Egee wrote:

hullygully wrote:jets wise - alter to suit your engine, carb, exhaust, kit, check plug colour thru' the rev ranges a must!!!!!
compression ratio etc... I know AF's do 2 x types of heads for 225's, higher & slightly lower compression ratio's, plus you'll need to check the piston/head squish clearance of 1.1mm -1.5mm, another must with todays fuels!!!!

Not a walk in the park then!

Relax egee. Buy sticky's, read it. Read mb tech site set up instructions. Build your engine sloooowly and methodically. It's just like following a recipe but a little bit more manly.

I'd never even changed a tyre on a lambretta this time last year but I read and read, asked what may or may not be silly questions. I did some stuff, and redid some of the stuff I did wrong but it's all part of the fun.

Just take your time and be thorough and you'll end up with a lovely motor.

It's waited 40 years so I don't think there's any need to start rushing now. Or maybe after 40 years the reaper is your main concern

dickie wrote:

Egee wrote:

hullygully wrote:jets wise - alter to suit your engine, carb, exhaust, kit, check plug colour thru' the rev ranges a must!!!!!
compression ratio etc... I know AF's do 2 x types of heads for 225's, higher & slightly lower compression ratio's, plus you'll need to check the piston/head squish clearance of 1.1mm -1.5mm, another must with todays fuels!!!!

Not a walk in the park then!

Relax egee. Buy sticky's, read it. Read mb tech site set up instructions. Build your engine sloooowly and methodically. It's just like following a recipe but a little bit more manly.

I'd never even changed a tyre on a lambretta this time last year but I read and read, asked what may or may not be silly questions. I did some stuff, and redid some of the stuff I did wrong but it's all part of the fun.

Just take your time and be thorough and you'll end up with a lovely motor.

It's waited 40 years so I don't think there's any need to start rushing now. Or maybe after 40 years the reaper is your main concern

Thanks for the gee-up, I'm useless in the kitchen but much better in the garage. It's just looking at all the bits in various stages of rust and neglect and wondering which bit to start first. Do I rebuild or restore, is the value having an original scooter or one that will be functional, running on modern mechanics? Oh, one thing I do know, is I can't wait another 40 years!

as Dickie said, take your time but try & use as many of your original componants (bearings, seals & gaskets aside) as possible, or be careful which Indibum parts you use!!!
try also to use as many cosher tools as possible too, cos it'll only end in tears, or a chisel/screwdriver embedded in the garage walls

hullygully wrote:as Dickie said, take your time but try & use as many of your original componants (bearings, seals & gaskets aside) as possible, or be careful which Indibum parts you use!!!
try also to use as many cosher tools as possible too, cos it'll only end in tears, or a chisel/screwdriver embedded in the garage walls

Is there a site that you can hire tools from, or does everyone have to lash out on their collection?

You don't need them all. Start with a flywheel extractor and flywheel holder; and a clutch compressor.

CHRIS in MARGATE wrote:You don't need them all. Start with a flywheel extractor and flywheel holder; and a clutch compressor.

I managed to get the forks out with make shift tools, but I can't think how I will be able to strip the fork springs without the required tool - unless someone has a bright idea

You'll have to buy the fork spring compressor.

never used a fork spring compressor, i use a large ring spanner , easy job.

martyn dwane wrote:never used a fork spring compressor, i use a large ring spanner , easy job.

I see how this works to remove the lower rubber buffers, how do you use it to compress the spring whilst jiggling the fork out?

martyn dwane wrote:never used a fork spring compressor, i use a large ring spanner , easy job.

It seems that your forks are of the GP variety.You just need to compress the spring via the link with a ring key,pull out the bottom buffer,pull out the ball bearing and the link can be removed.On a pre-GP model you need a compressor because were as the GP has a ball bearing,the pre-GP models have a fixed ball and cannot be removed.

I think his first call for help was regarding a SX 200, so he'll need the compression tool
where in the country are you?

hullygully wrote:I think his first call for help was regarding a SX 200, so he'll need the compression tool
where in the country are you?

Yes they are SX200, out if curiosity. I emailed a couple of suppliers to ask about their compressors. Explaining the rubbish I previously received and asking about the quality of theirs - guess what? No replys!!