LCGB Forums

Troops -- just doing some research, I've got a stage 4 200 lump with a 42mm AF clubman breathing through a standard box with 26mm jetex. Thinking of changing to a 25mm delly but want to breath through a standard airbox -- is it worth the change? Thoughts welcome

how does it run at the moment?

Tried running 25 mm through my airbox on GP 200 and in the end run it open as would not breathe properly with airbox attached.

You might want to check the neck on the airbox, makes sure the scoop is open and maybe try one of the wire type filters instead of a paper based one.

edit:
BGM was the one I was thinking of.

also modify your airbox , ive done quite a few now where i remove the baffle and change the inlet size to 50mm , scooter center actually sell them like that if you check them out

missing lynx wrote:how does it run at the moment?

Runs well, bit boggy around town but most of my miles are rally miles, but is greedy on the fuel, jetted well and been up and down the country, was just wondering if it was just a plug in and play with a 25mm delly breathing through an unhampered box, me thinks not.

MB developments sell a big bore standard looking air box or as I've done several times when fitting this carb; drill the side of the box, between the toolbox and filter box, with about 6 13mm holes. Works well at zero cost. Sounds throatier than normal though.
Paul

If it runs well with a 26mm through an air box there's no reason why it shouldn't with a 25mm carb and I think you'll find the delly easier to set up and more economical

Scooter Paul wrote:MB developments sell a big bore standard looking air box or as I've done several times when fitting this carb; drill the side of the box, between the toolbox and filter box, with about 6 13mm holes. Works well at zero cost. Sounds throatier than normal though.
Paul

Cheers for the tip Paul -- that was going to be my next question re the holes & how many? -- G

If you use the wide necked TV2 air box you wont need to drill holes in it
Im running a 25mm delly through the air box on a muggy 186 and 42mm af clubman* and it works a treat


*although I just changed the pipe to a bgm bigbore yesterday to see if there is any change

This might be stating the obvious, but my intention is to offer some advice.

The standard layout for Lambretta is to draw air external to the enclosure created by the panels & bodywork. The air is fresher, cooler air than would otherwise be drawn if holes are added to the air filter box.

If there is no alternative than to add holes, then understandably, it will have to be done.

However, many years ago, I acquired a TV200 running an Amal Concentric Mk I on a ‘cut & shut’ Royspeed manifold running the air box with precisely that modification. I bunged up the holes with blind grommets by means of experimentation & there was no perceptible difference apart from less of a tendency to heat-seize during prolonged caning…..

....And here's one i did earlier :- http://i423.photobucket.com/albums/pp31 ... arison.jpg

Standard SIL airbox, internal swan neck removed. If you feel like enlarging the hole in the frame loop, it might be possible to fit a larger diameter tube between box & flange. As it is, I've had to increase the main jet size to 125 on a DellOrto SH2/22 carb to richen the mixture on a 200 Stage 4 lump. Sounds throaty - much more induction noise than standard.

128 euro for an air box !

Come on.