LCGB Forums

Need some advise on PWK manifold's, and what PWK users have found, & is the best solution

Below is an image of my setup using a Polini CP (PWK copy) and MB 200 manifold
yes it fit's, but it's not ideal

There's three issues with this setup that I can see:
1: The choke cable exit fouls the toolbox (the throttle is not perfect)
2: The fuel lever is routed to clear the choke, but not ideal at an acute angle
3: I can fit a remote filter but it would be on the angle where the filter needs to sit between the fuel tank and toolbox

I have found Buzz sells what is described as a 200cc PWK manifold
https://www.buzzsolomoto.co.uk/scooters-parts.php/view/manifold-24-30mm-pwk-200cc/id/003911

Has anyone got any experience they can share please?
Would Buzz's manifold solve any of the above, or does it just introduce other issues

I’ve got one of these with mine , no problems with fitment , can’t take a pic as I’m at work if I remember I will try get one later

https://www.riminilambrettacentre.com/e ... gomma.html

I think that the PWK is a great choice as it is an efficient carburettor. With its built-in measures to avoid flooding, an air filter can be run successfully without the worry of hot re-starting.

One of the other attributes is the efficiency so that the 30 mm bore equates to something like a 34 mm of a less efficient carburettor.

(What is not so good is that the fuel line requires a filter or the jets will block up)

So “Good Luck!” if the aim is to run a standard air filter box, as a 30 mm choke will require something like twice the volume of a 22 mm SH type simply to maintain the same RPM. Start to go over the '6900 RPM' intent of the GP200 as might be expected, & keep that left hand hovering over the clutch is my best advice!

Consequently, I see little point in buying a manifold which might place the carburettor in the region where standard bellows can be fitted if the standard bellows &/or filter stifle the thing!
Better to modify the ubiquitous CDC type manifold to fit, getting it as short as possible, fit a UJ (Universal Joint) or two to the fuel lever rod & an angled tube to the choke cable.
Filtration can then be by an elbow (as large as possible that will fit) & a filter, although @ the weekend a foam sock was just stuffed onto a 34mm PWK & it worked well enough

Thanks for the feedback so far

just to clarify, which I should have made clear, I'm intending to use a remote filter (like breath sweet, or similar), and never an air box. As I'm well aware I'll not supply the air volume without some serious modifications to the airbox

The RLC manifold looks like the carb is swung to a more perpendicular angle to the frame than the MB, moving the choke cable away from the tool box & fuel lever, meaning the fuel tap/lever can be moved to a less acute angle, and correct the alignment for the remote filter
similar, I think to the Buzz one's in the link in my initial post
The problem I could/would then introduce is less distance between the front of the carb and the panel for the remote filter hose.

I do have a short CDC which I could try

I was looking at the fuel lever universal joints on Andy Francis's web shop last night. But I couldn't make up my mind if these were a worth while upgrade as I know of no one with one fitted..

nsaints wrote:Thanks for the feedback so far

just to clarify, which I should have made clear, I'm intending to use a remote filter (like breath sweet, or similar), and never an air box. As I'm well aware I'll not supply the air volume without some serious modifications to the airbox

The RLC manifold looks like the carb is swung to a more perpendicular angle to the frame than the MB, moving the choke cable away from the tool box & fuel lever, meaning the fuel tap/lever can be moved to a less acute angle, and correct the alignment for the remote filter
similar, I think to the Buzz one's in the link in my initial post
The problem I could/would then introduce is less distance between the front of the carb and the panel for the remote filter hose.

I do have a short CDC which I could try

I was looking at the fuel lever universal joints on Andy Francis's web shop last night. But I couldn't make up my mind if these were a worth while upgrade as I know of no one with one fitted..

My preference is for a downdraft manifold, which also gains space for whatever is attached to the carburettor, like for like. You may need access to a lathe to modify a CDC manifold correctly & it's worth mentioning that the rubber connector can be had with the correct grooving to fit & in compact versions for less than a tenner....Too many over-tighten the worm drive hose clips which makes the things too compressed & then fall off.

I've been using UJ's for decades, but wouldn't dream of sourcing them from a dealer. If you search t'internet with:

model boat universal joints

you will see how cheaply they can be obtained.

As for the elbow to reroute the choke cable, they are also available if you look on any of the 'ped' sites.

Air filter foam is available that can be hot-glued to form whatever you like, shapewise, allied to a silicone elbow/bend that is best if obtained so that it has an increase in size going away from the bellmouth, say a 65mm to 50 mm reducing elbow/bend. What you should bear in mind is that "size matters" & that any elbow is in effect a plenum & should not be restrictive. In tests, a standard rubber elbow for a SH2/22 on a well set-up 175 with a 26mm carburettor stifled the engine even with no filter fitted, so how they get used on kitted engines costing hundreds of pounds is beyond me

the Buzz manifold is similar or may even be the Scootrs type which I used to good effect and sits the carb square and level with no fouling of cables and enough room for a Breathsweet filter the Rimini one I suspect would be similar. I changed to a reed valve manifold which still has room for the BS filter but does not sit as level has to turn a bit clockwise to clear cowling screw. not sure how this affects the fuel level.

Also consider the MB / BGM Flange type manifold which sits more square and level.

Thanks for all advise ^^

Managed to source a PWK specific manifold. Buzz had no stock, but Martin at Just Lambretta came good
The Manifold was bargain basement price, and needed some minor fettling

Here's the fitment of the carb. Cables clear the toolbox and the fuel lever is no longer at a crazy angle
I've since been told a 30mm PWK doesn't like a remote filter, so I'll have to get my head around that if the carb is too stay (after all that!!)

[quote="nsaints"]Thanks for all advise ^^

Managed to source a PWK specific manifold. Buzz had no stock, but Martin at Just Lambretta came good
The Manifold was bargain basement price, and needed some minor fettling

Here's the fitment of the carb. Cables clear the toolbox and the fuel lever is no longer at a crazy angle
I've since been told a 30mm PWK doesn't like a remote filter, so I'll have to get my head around that if the carb is too stay (after all that!!)

[/quote

Dunno who told you that, but one reason I really like the PWK is the ability to run a capable filter without issues such as hot start/flooding without having to drill leak holes as with some Dell'Ortos! That is because the design incorporates an overflow in the bowl, just where it needs to be, because panelled Lambrettas have heat soak issues when the engine is stopped. As mentioned previously, a 34mm PWK runs absolutely brilliantly with a homemade foam filter, either via an elbow or as a 'sock' just pushed on.

The only trouble encountered has been the jets getting blocked because an inline filter was not originally fitted, but that has now been rectified.

PWK carburettors are fitted as original equipment on some equipment, so the proof of being compatible with an air filter is there to see.

(My Mate may have got a bit carried away with his right hand with his rebuild ('Old School' pattern piston, cast iron barrel) as it had a soft sieze so the top end needs to come off soon, but the 32 pilot may be a bit too near the margin.....)

started a new thread on the remote filter topic
viewtopic.php?f=6&t=11602