whats the verdict on 24mm PWK carbs ?

[johnny650]

There are a lot of cheap OKO /Keihin PWK carb copies on the net cheap at the moment.
What are the pros and cons of using one of these often unbranded PWK type carbs on a 185cc cylinder kit to replace a 22mm jetex?

I'm thinking in particular about connection of the throttle cable and also the choke as I see most of them have cable chokes. I see you can buy a manual choke lever assembly seperately on ebay though so thats not necessarily a problem.

I'm keen to hear from anyone that has tried these carbs for personal experience before I order one up.

[johnny650]

this is the type I am referring to
pwk by John, on Flickr

[johnny650]

has no one ever used a PWK ?

I'd appreciate any advice on cable connections , filtering, setting up, base line jets , potential problems etc

[coaster]

The design is fine but the quality of some can be a bit hit and miss. I have used a couple, one an OKO and the other a BGM branded version. I also have a 24mm OKO that will probably go on my Vega at some point. Fitting is very straight forward but you will probably need a complete new throttle cable , the choke should be ok though. You will need to buy a kit of jets and needles too.

[EddieStone]

I'm running one on my Lambretta chop at the moment. It was a vast improvement over the Indian Jetex that was on it before, not that that says very much.

For the throttle cable I used a gear cable from wilko with the nipple at the carb end and a solderless nipple at the throttle. It's a chop so I bought one with a pull up choke.

I found that 5mm Dellorto jets fit - the last turn is tight but it works. The jets you get with it are unlabelled so you have no idea of the size, so it's best to buy a set. There are instructions online to improve the flow of the needle valve and pilot circuit which are worth doing if you are careful with a drill. There are really good instructions on setting up a carb online - no main jet in to dial in the pilot (tick over jet), then dial in the main jet, then adjust the needle.

They're useable carbs for a low tuned engine. I don't think I'd put one on a highly tuned motor where the mixture might be a bit more critical, but for most uses they're perfectly OK, and a vast improvement over an Indian Jetex.

[johnny650]

thanks Coaster and Eddie that is just the feedback I needed. I'll go ahead and order one up .
I read somewhere I think on MB Dev that its best to blank off the accelerator pump ?

I found a 20 piece kit of jets and needles yesterday so I'll probably order that up when the carb arrives.

Thanks for the tip about the throttle cable that sounds pretty straightforward. it has to be a whole lot easier than trying to tighten and loosen the Jetex nipple without removing the carb . What a dreadful design putting the cable connection and throttle adjust at the rear of the carb behind the choke connection grrrrrr my Tourettes has definitely found a new level this past few weeks

I found several helpful setting up guides ...this one appeared to be the best . Hope that its ok to post a link to a technical guide that is directly related to this thread title . If its not acceptable my apologies in which case perhaps someone would kindly remove the link
http://www.mid-atlantictrials.com/Instal.html

[johnny650]

A quick question.
The 24 PWK carburettor comes with a manifold rubber which has an internal diameter of 34.5mm according to the spec .
How did you attach the manifold rubber to a small block 22mm manifold spigot which has an external diameter of 30mm .

is there a special manifold I need to buy to fit a PWK to my cylinder or is there some sort of adaptor or reducing bush

[Minority]

https://www.scooter-center.com/en/bgm85 ... 98_5_12_12__

[Minority]

Oops sorry the bgm pro manifold is only for 200 stud spacing.

[rosscla]

You need to get the right manifold for the carb and your cylinder.