PWK for RB20

[wrekkah]

Anyone running a BGM PWK carb on their RB20?

If yes, what size? How does it run?

Thanks

[C*NTSPEED]

im not but a 28/30 should do but why a bgm? koso is same carb and half the price?

[wrekkah]

BGM brand is cheaper than KOSO brand in the states.

Thanks

[coaster]

Nothing wrong with the OXO ones that ScootRs sells either, mines been on my muggy 186 for well over 5,000 miles now, still on original rubber and once I got the jetting sorted it has been pretty near faultless (kiss of death saying that )

[MarkH]

Of all the Keihin copies, the BGM has the best casting I've seen. The OKO carbs I've worked on have been rough and in some cases warped (hmm why won't any of these new slides slide!). The Koso is rougher as well and nowhere have I seen them be cheaper - not even close.

I've got a genuine brand new Keihin PWK 28, new BGM PWK 28, and used OKO PWK in front of me while I type this and the visual quality is night and day.

Just my opinion.

[Train Driver]

MarkH there has been a few questions about the 28mm mikuni on here and i know it was not their best carb how much better is a genuine Keihin PWK 28 and would it be over the top for a rapido 225, i know someone who is struggling with his 28mm mikuni.

[MarkH]

PWKs are relatively easy to jet and are very simple as far as carbs go. I don't think it's overkill for any 225.

The TM28 can perform well if you manage to get it set up - emphasis on the word IF. I find them to be tempermental at best. I suppose it's all relative to your experience, but I would say the PWK is better than the TM28 in terms of setting up. Performance you would have to measure on a dyno using the same topend/exhaust.

If someone has managed to successfully dial in the TM28 on a variety of setups and have them run well over a long period of time I'd love to know their secret. On paper they seem well suited to tuned Lambrettas. It's a shame they don't perform as well as the TM24 really.

[scootRS.com]

Regarding OKOs, the only time we've EVER heard of a warped casting/slide issue was about 4 years ago. Maybe a small batch. We've used them on every performance scooter for many years and have never seen that, nor heard it again, so not an issue.

Nothing wrong with the OKO ones that ScootRs sells either, mines been on my muggy 186 for well over 5,000 miles now, still on original rubber and once I got the jetting sorted it has been pretty near faultless

That's what we find. Cheap carb, good performance. Love that combo

The PWK variants are all made in Taiwan, including the YSN brand (sold by BGM). There are different external finishes, but what matters is how they perform and I highly doubt you would see a performance difference between any of them - though the 28/30 aspect of ours is a plus -, so for a Lambretta ultimately it comes down to the cost of an entire package including manifold, mount, choke conversion, jets, etc. Our kits are $109/£67 complete, no idea what others are. Shop around.

For an RB20 a 28/30 sounds perfect and what we'll be using. We used them on TS1s all the time. We've used our 28/30 on an RB22, though a bigger carb would add a bit. If you've never seen one firsthand, you can see it on the RB22 below on a custom ordered scooter, sounds great:

[wrekkah]

I've run a 24mm OKO from ScootRS and while it performed nicely, it was very thirsty for petrol.
I have a TM24 on the engine now and I'm very satisfied with performance and gas miliage.

I'd like to put a Mikuni TM28 on the RB but the problems that Mark has described and I've read online concern me. I feel a TMX35 is too big and a TM24 too small for the RB20. Anyone else have an opinion on this?

I currently have a 24mm BGM PWK on a Casa185 kit and I've been pretty happy with the results so that made me lean towards the BGMs for the RB. I guess I probably can't go wrong with a 28 or 30mm.

I know the Delorto route is another option but I'd like to stick only one or two carb styles as acquiring a good set of jets for the different types of carbs can get expensive.

Thanks for the replies

[Stokie]

Of all the Keihin copies, the BGM has the best casting I've seen. The OKO carbs I've worked on have been rough and in some cases warped (hmm why won't any of these new slides slide!). The Koso is rougher as well and nowhere have I seen them be cheaper - not even close.

I've got a genuine brand new Keihin PWK 28, new BGM PWK 28, and used OKO PWK in front of me while I type this and the visual quality is night and day.

Just my opinion.

What about the Stage6 PWK copy - anyone tried one of those ??

OK now I'm confused - just looked at the Lambretta Spares BGM carb page and spotted this



So what's the deal, are Koso & YSL (BGM) carbs the same ??
They do also have a pic of a carb that says YSL on the side !?