Dellorto PHBH

[Devlam]

Anyone tried these? Seems like a good price....

http://www.wasp-performance.co.uk/onlin ... 30-BS.html

[rosscla]

You'll spend another £40 on the right jets and a cable choke ....

Cam lam will do one for £99 or thereabouts jetted to your reqs

[Special X]

You'll spend another £40 on the right jets and a cable choke ....

Cam lam will do one for £99 or thereabouts jetted to your reqs

Wasp will sell you the required jets with a PHBH28 for £5.08 (they supply the 28 with AV264 atomiser, so would cost £75.07 fpr a PHBH 28 with the right jets. You'd need to buy a 115 main, an X13 needle

For a a PHBH 30 you'd need to buy a 120 or 122 main, X7 or X13 needle, and AV266 atomiser so the total cost with jets would be £79.06. It may be that you could use the supplied X2/AS266 combo and just change the main jet if you're lucky and bring the price down to £71.68 *

Keen price.

Cable choke conversion £5.99 so total with 28PHBH £81.06. With 30PHBH £85.05. or £77.67*

[nelson pk]

You haven't even mentioned what set up your using and people are giving out jet specs!
When a carburettor comes supplied jetted, its only a rough guide remember. Never, never take it as gospel that it is exactly what you need for your spec

Bloody good prices on all carb components though!

[Special X]

Rough ballpark areas for most motors nelson. Point being made is you can run most engines on a 28 PHBH on an AV264 so long as you use an X13 needle. And most motors on a 30PHBH with an AS266 or AV277 and an X2 needles (with AS) and X7/X13 on the AV.

You'll be in the ballpark with 115 main on the 28 and 120/122 on the 30 with any piston port as the increase in vacuum on more powerful engines drags more air past the jets and increases the fuel delivered. Need bigger jets on a reed valve cos the inlets are so big there's much less vacuum.

Simplified I know but essentially correct . . . .

They would work with a smallblock Mugello, Casa, 175 stage 4 (best with 28 carb) Large block 200/225/230 mugello, 200/225 rapido, 200/225/230 stage 4/5 iron, and quite a few others. Feel free to recommend other jettings for these (as a ballpark) but please don't blow anyones engine up just to have a go at me.

[nelson pk]

Rough ballpark areas for most motors nelson. Point being made is you can run most engines on a 28 PHBH on an AV264 so long as you use an X13 needle. And most motors on a 30PHBH with an AS266 or AV277 and an X2 needles (with AS) and X7/X13 on the AV.

You'll be in the ballpark with 115 main on the 28 and 120/122 on the 30 with any piston port as the increase in vacuum on more powerful engines drags more air past the jets and increases the fuel delivered. Need bigger jets on a reed valve cos the inlets are so big there's much less vacuum.

Simplified I know but essentially correct . . . .

They would work with a smallblock Mugello, Casa, 175 stage 4 (best with 28 carb) Large block 200/225/230 mugello, 200/225 rapido, 200/225/230 stage 4/5 iron, and quite a few others. Feel free to recommend other jettings for these (as a ballpark) but please don't blow anyones engine up just to have a go at me.

Not having a go at you at all
I just dont think you can turn around and say, well with a 28mm PHBH you'll be alright with a AV264 and X13 needle or an AV266 and an X7 in a 30mm PHBH (in my opinion they are pretty weak combinations at just over 1/4 throttle when cruising, especially in 225 engines)......it's just not that simple. The pipe your running will have a massive difference on jetting and so will timing, filter/no filter, manufacturing tolerances on the kit or top end etc, etc so you can't just say it'll work for this that and the other kit.............that advice is more likely to blow an engine!
I mean the difference between a casa 185 kit and mugello 225 or race rapido 225 can be huge!
I am also quite aware of the venturi principal and how a carb works but fuel demand will change dramatically between low revs (when the exhaust is less efficient) and when you hit the power band on an expansion pipe for example. So much so that you may have to run it over rich at low revs when your off the power so when the pipe is working at its most efficient the fuel mixture is correct and not dangerously weak.
It is not personal at all, i dont know you, i just thought it was the wrong advice to give.

[soosh]

Rough ballpark areas for most motors nelson. Point being made is you can run most engines on a 28 PHBH on an AV264 so long as you use an X13 needle. And most motors on a 30PHBH with an AS266 or AV277 and an X2 needles (with AS) and X7/X13 on the AV.

You'll be in the ballpark with 115 main on the 28 and 120/122 on the 30 with any piston port as the increase in vacuum on more powerful engines drags more air past the jets and increases the fuel delivered. Need bigger jets on a reed valve cos the inlets are so big there's much less vacuum.

Simplified I know but essentially correct . . . .

They would work with a smallblock Mugello, Casa, 175 stage 4 (best with 28 carb) Large block 200/225/230 mugello, 200/225 rapido, 200/225/230 stage 4/5 iron, and quite a few others. Feel free to recommend other jettings for these (as a ballpark) but please don't blow anyones engine up just to have a go at me.

Your bang on with the 28mm spec for my iron kit with both pm and jl3. What was interesting was even before it was on dyno,that's what was recommended by Jerome.

[Adam_Winstone]

Soosh, is this with a totally standard needle or has Jerome 'worked' it. With the modification that he and some other dyno tuners carry out it becomes virtually impossible to know whether you are comparing like like for like. The modified X13 that I left with in my Muggy, after a session at Jerome's, actually meassures up (micrometer) as being the same as an X2... and the X13 and X2 are VERY different in operation and atomiser requirement (based on the different taper length, even though shaft and tip diameters are the same).

Your needle may indeed be standard... but it very well may not be, any idea?

Adam

[paulnobodyimportant]

I'm still learning carb setups and nearly there through trial and error, ie forum advice and plenty of plug chops. And over the last few months, I have got a real feel for generally sensing how the engines revs through the range, both static in my drive and then out on the road and validating with plug chops. I know that I could put it on the dyno and have done in the past, but for me there is nothing better than understanding your engine and the variables that go along with it.


However, along the way I must have read that a X13 needle always goes with AV264 and X7 with AV266. I say this as I have a 30 PHBH carb that I am trying to set up and with X7 at top position (P1) in a AV266, its still rich up to half throttle. So, I am thinking of changing to the weaker AV264 atomiser, but keeping the X7 needle.
But am I correct in thinking this, or should I try the X13 needle 1st.

Explanation gratefully recieved.

Thanks

Paul

[nelson pk]

Its very difficult to give carb settings over the internet or phone without actually looking at and riding the bike etc which was my point in the first place.
However, i agree that to learn about carbs and the feel of too rich, too lean is best learnt by trial and error and experience which can be expensive! Naturally, reading up on tuning two stroke carbs helps but to actually learn h
how to jet a carb for a 2 stroke engine that is tuned extensively with expansion pipes on designed to give you quite a harsh power band is not as simple as some 2 stroke carb tuning guides lead you to believe!
Do you have an egt fitted? If your playing with carb settings it will help massively as you will be able to see at what carb position and at what revs your bike is getting hot.
Also the choke test is a good way to see if your lean or rich. Pull your choke on and if the scoot splutters and holds b
ack a lot your rich enough. If it makes no difference or makes the bike pull better it's likely your too lean.
Have you tried different slides 40, 45, 50? Sometimes a 40 slide can be too rich for low rev's, pulling away etc between 1/8 and half throttle leading you to try weak atomiser/needle combos. This could then cause the bike to lean out at higher revs when you roll back between 1/4 and 1/2 throttle to cruise.
Always do choke tests though and keep an eye on heat.