PHBH30 Basic Jetting Mugello 186

[nickwill]

Hi all,

Have recently purchased a PHBH30 which came 'ballpark' jetted for a Mugello 186 with MB/BGM bigbore, and remote Ramair filter.
No details were included in the box, but have checked and listed current setup which is as follows:
Needle X4 second clip down.
Choke jet 70.
Main 100.
Pilot 53.
Atomiser AV266.
My first thoughts before I start fitting and testing are that the main jet seems small. Also I don't recall seeing anyone using X4 needle which I assume is leaner than X2 but nowhere near X7/X13 which seem to be most commonly used.
I appreciate I need to test and adjust for my engine, but an thoughts on the current jetting would be appreciated. Thanks.

Nick

[bolzenanker]

Have you checked this out, guidance from the CamLam website:

http://www.lambretta.co.uk/downloads/carbjetting.html

[nickwill]

Hi Bolzenanker,

Thanks. Yes, have looked at settings on various forums and websites, and as the carb kit actually came from Camlam I checked the said list, which doesn't mention an X4 needle, or a main jet as small as 100. Not that the combination is necessarily wrong. I'm trying to check with Camlam but difficult to get through on the phone, so while I email for info just thought I'd get some opinions from the experienced Dellorto users out there. I've only used Keihin and Mikuni on the Mugello but the PHBH is obviously very popular with other owners..

Nick

[bolzenanker]

No probs, just checking. I do have a Muggy 186 with PHBH 26 and Gori 50mm which runs very well. However I can't remember the jetting, and it probably is just a little too different to be relevant.

[bluebob]

no expert but my 28mil phbh ran with a 110 main on a cheap 185 ally barrel so yes seems a little small to me as I assume your muggy to be quicker and thirstier.if you decide to start rich and work down buy a box of main jets from mb,about 10 in a box,in your range.i recently bought 3 main jets for experimenting,still not perfect and cost more than a box from mb.

[scooterstu]

Not sure if this will help but i have a 200 Mugello with a 30mm PHBH dellorto and a BGM Clubman.
The jets are as follows
AV264 Atomiser
X13 Needle (not sure which clip)
52 Pilot
115 Main
and a 45 slide.
I set this up with the help of Bristol Lambretta club website but that was for a JL3 exhaust. I have changed the exhaust since then and had it dynoed and it didnt require any changes and returned 17 BHP

[nickwill]

Many thanks for the replies. From the data on various websites and forums I'm thinking there are many different ways to approach the jetting of a PHBH, and I would guess that combinations of rich needle/atomiser combinations with weak jets might achieve similar results to weaker needle/atomiser with richer/bigger jets. I'll start with what's in the carb, do some (careful) testing, and have spare needle/atomiser and main jets to adjust if needed.