Part 3: How to set-up a Dellorto PHBH carburettor on almost every Lambretta & Vespa scooter!

[@davidblagden7894]

Cheers Dan, nice ending to the trilogy. I will be upgrading in the very near future. Thanks 👍🏼

[@brendanwalker9759]

Being a new scooterist i have been watching Dan's video's with great interest. Thanks mate. I am learning loads from you and my mate " Big Boy " Mark

[@andydavidson]

This has series of vids has been a great help to me, I've had a PX with a Malossi 210 rv and a 30mm Dellorto PHBH in the garage for about 10 years, never been on the road, guy I bought it off had had the engine work done by Terry Sheperds son. Over the last few weeks I've been putting the scoot back together, gave it a run a few days ago and it didn't exactly run right, seemed to act like the jets were dirty, pull the choke out and it picked up, had the carb apart and my jets seen to be too small, 130 main, 70 choke, av260 atomiser, 55 pilot and 225 choke, needle is a x3, going to order some new jets and needle and see how it goes. cheers 👍

[@ericwalker2172]

Once again Dan excellent information 👍

[@ericwalker2172]

Hi Dan hope you can help me out here I’ve got a RT 195 kit with a BGM clubman and just replaced the 25 PHBL carb to a 28 with no filter on on your recommendation l jetted it with x13 needle 2nd clip 55 pilot 264 atom 125 main 40 slide more or less identical to my SX 225 kit I took it for a test drive but found it wouldn’t drive through the gears without pulling back sounds to rich to me should I try the top clip or a leaner needle🤔🤔🤔🤔👍

[@drunkmunkey6969]

You need to do plug chops, to decipher where it is rich and where it is lean, and adjust accordingly.

[@nickmassey9104]

Great series of videos

[@TheSteelweasel]

good vids some good advice but i remember going to the AMAL FACTORY back in the 80s and getting a carb built as i wanted cost me 59 pounds . good days

[@MrCamohoj]

Firstly Dan great set of videos fantastic load of info but as always when watching these i soon begin to realise what an absolute novice i am when it comes to scooters , I haven't a clue about jetting , kits , slides what about bringing a book out with illustrations showing the different setups and variations of carb, exhaust and so on. I think it would be much appreciated with scooter enthusiasts.

[@drunkmunkey6969]

I might do a guide in Scootering, thanks for the input/idea. Cheers.

[@craigsavage118]

Hi Dan - I’m currently learning to tune a Rieju 50cc. No youtube when I was 17 in 1986! Main jet changed to 115, New CDI unit for higher revs and 14 tooth front sprocket instead of 11. Full Vocca race exhaust. The bike seems to bog down at pull off then rip your arms off in the power band. Will raising the clip on the needle help? Ticker over is fine and revs well when standing and not under load. Thanks.

[@exsoulagent]

Good info 👍🏻

[@vespasandengines]

This series was a lifesaver! Jetting was great just tweaked a little on the main, but was great to get a reference point... Building an extra engine and wanted to ask any settings using a pwk 35 on a Vespa? Can’t find any useful information anywhere to get any decent jetting

[@scooterpembs]

A great and educational intro into this carb type, thanks. But please someone help... 30mm open mouth - How much fuel should be blowing back out during normal running and why will it not start unless I cover the carb mouth. (55, AV266, X13 2nd clip, 40 slide, 130 main on BGM177, 60 crank, JL pipe)

[@dazzyluker]

cheers very usefull

[@chriswalker3049]

Hiya dan. I have a malossi 166cc with reedvalve and racing crank and 26 bhph with bgm bigbox touring. Any idea on set up.

[@Geoff2468-wb9dk]

Hi Dan, have you ever dyno a SST265, if so what were the settings please ?

[@alexandercajko700]

Cheers Dan! Could you please recommend a PHBL carb size for me? I’m building a RT195 (60/110 crank so it’s a 200) V4 clubman, standard Li150 gearing (5.2 ratio) as I favor acceleration over top speed. BGM ignition. Some people recommend a 30 mil carb but my gut feeling is it’s overkill and feel that 28 mil is more than enough and would not limit any power. I don’t want to buy an oversize carb and waste fuel. But I also don’t want to limit performance by placing a 28. Thanks in advance!

[@dhumph1969]

I'm having problems setting up a new Dellorto SHB 16:16 on a 1983 PK50 (Don't laugh) Are these normally a straight from the box fit or should I be changing jets? It just will not fire up. Starts with easy start in cylinder so engine & plug are ok. Checked and re checked for air leak. Tried bypassing the fuel tap and feeding fuel directly into the carb. It sounds like it's trying to fire with a bit of throttle but just won't have it. Seems to be a fuel starvation issue as there's no fuel smell when i take out the plug. Doing my head in

[@bolti1000]

Dan hi. Here’s a question in respect to fine tuning. When do you go away from moving the needle clip to altering the size of the main jet. Let’s say for instance. You are running a 125 main on second clip setting and it bogs on open throttle. Is it best to move the clip up or come down to say 122 or 120. Thanks for great info. Just interested to know the ‘cut off point if you get my meaning. Cheers Bolti

[@drunkmunkey6969]

It’s a bit more in depth than this there is upward flowing overlap, but to try and simplify it, I’d suggest you focus mainly on the clip for 1/8-1/4 throttle settings. Then needle and atomiser combo for 1/4-3/4. Then the main for 1/2-1 (full throttle).

[@out-the-backshack3571]

Changed over to your recommendations and mine was bogging down like crazy low down ,one it picked up it was ok

[@drunkmunkey6969]

Let me know pipe, kit and whether or not you run a filter... I’ll see if I can suggest a tweak. Was it the 30mm?

[@out-the-backshack3571]

@@drunkmunkey6969 yes mate 30mm dellorto, pipe kegra jl and it's a mick abbey tuned 185 kit

[@out-the-backshack3571]

@@drunkmunkey6969 no filter mate

[@drunkmunkey6969]

Sounds like the AV266 was too rich for the smaller capacity CC? Try the AV264, but follow up with plug chops.

[@out-the-backshack3571]

@@drunkmunkey6969 already had that in ran fine with a 50 pilot dropped it down to 52 to see tomorrow weather permitting

[@georgebashton5227]

Hi Dan I have watched all 3 videos, very interesting, especially as I'm new to setting up my Lambretta S3 150, I have fitted the new Casa 200 sport barrel with associated piston, the crank is a standard GP, I'm using the vape 12 volt (non viable), ignition system timed at 17 degrees btc, my carb is a dellorto phbh 28mm, with the 55mm pilot, AV266 266 atomizer 40mm slide, 350 float valve (came fitted), X13 needle on 2nd from top notch, I have fitted an Avanti xbox exhaust, can you please recommend a main jet? Cheers George

[@drunkmunkey6969]

Always start large and work backward. So for example, if you try a 130-135 main jet on a sporty piston port motor with a sporty clubman, chances are it will be a tad too big... but it'll give you a reference point, and as you scale back, you will find the sweet spot as the engine clears and starts to perform. You then might, for example, end up around 125-128, but this will be conformed by test rides and plug chops.

[@jasonfrost7097]

Cheers for the info … just put a RT 195 kit on my li … with 28mm dellorto the guys who sent me the carb didn’t jet it to suit the head… after I asked them 2… have ordered all the right bits now to do it myself .. what would you recommend for turns on the mix screw and tickover?

[@nielmurphy1698]

Hi Dan I have 28m dellorto with ram filter on my lambretta RT195 main jet 118 pilot 55 slide 40 av266 x7 needle 2th notch down taken it for a good spin temperature gauge hit 185c very hot I was thinking of changing to x13 needle 2th notch down would that cool her down

[@drunkmunkey6969]

If it doesn’t bog down, then yes. But also make sure ignition timing is 17 deg BTDC, and that squish/compression ratio are correct.

[@clivewest1440]

Great videos. Im running a rt195 kit with 60x110 crank, reed valve with boost port, bgm v4 pipe with a 28mm phbh carb any starting points jetting wise. Many thanks 👍

[@drunkmunkey6969]

Love those little 195 kits. It traditional piston port format they were a bugger to get anything bigger than an AV264 into. But with the reed-valve/boost port conversion, and the longer stroke, I’m sure an AV266 will work. The only reason it wouldn’t, is if the pipe gasses up too soon. Try 55p, AV266, X13 (2nd), 40 slide, 300 tap, mix screw 1.5 out, and a 130 main. You’ll have to do plug chops from there, to fine tune...

[@SMURFY1967]

@@drunkmunkey6969 Similar to above Reed tuning done by DSC but a stainless TSR Evo. 55p, AV266, X13 (1.5 might be 2 can`t remember that bit), 40 slide, 270 tap, mix screw 1.5 out, and a 140 main. 20 hp 17.4 ft/lb torque 76 mph on the GPS. Great set up pulls excellent from 5000rpm I have a 5 speed AF box running 17/47 34t 5th.

[@rogershortt9529]

Great series! Very kind of you to share all those years of data - would you have similar info for mikuni's as well? cheers! Roger

[@drunkmunkey6969]

Thanks Roger, yes, I’ll try and put something together.

[@philipbulman8048]

thanks for the video, Im looking to get a little more out of my GP150 with sterling box, if I fit the PHBH30mm what jets do you suggest, and should I fit a rubber mount onto manifold - no air filter, with my current standard 22mm on full throttle its just intermittently cutting out every second and top out at 50mph or so as if you are running out of fuel, sure its the carb set up?

[@drunkmunkey6969]

First check your fuel flow from the tap to make sure it’s flowing 1 pint per minute. Then look at changing carb as required to suit your setup.

[@philipbulman8048]

Many thanks, dont think a pint per hour is flowing, ordered new hi flow tap

[@syl20bora]

hi i got a phbh 28 and a pinasco alu 177CC on my vespa Px...hard to set the carb what do you think???too big for the 177cc???

[@drunkmunkey6969]

No, not too big. 28mm can be a bit fiddly, I prefer 30mm PHBH.

[@syl20bora]

@@drunkmunkey6969 thank you i have trouble during the acceleration on top of each speed...any recomendations about how to set it properly please?

[@fredbert4048]

my vespa 177 rebore with 28 delly was running wow great ..then 60 mile run ...dead .. plug mega dry ...help do i remove put si back on why are all the manifolds built for tilt ???

[@drunkmunkey6969]

Try jetting as per my video first.

[@stephensharp3120]

Hi Dan I have a t5 mallossi 172, no porting std crank 30mm phbh mallossi kit, bgm big bore exhaust, carb kit come with 50 slide x2 55 pilot needle av266 130 main, so change to your base settings 40 slide av266 x13, runs better but can't get to tick over right with out it spoiling how it revs and settle down after revving. Any help would be appreciated. Thanks Stephen

[@drunkmunkey6969]

OK, let’s see if I can help. What is the mixture screw doing at this point? Have you got that dialled in yet?

[@stephensharp3120]

@@drunkmunkey6969 hi Dan the mixture screw I have two turns out because the revs down better there.

[@ramon76]

Excellent mate!! I hve a 28phbh ok a bgm 225 and bgm big box exhaust.... I live At 3000 feet.... Having trouble, runs rough, caughs.... I am trying to get the bits to get it better... Any advice? I run High 120 Low 50 Needle x2 (got a x5 near) Atom 264as And the rubish 200 slide... Know I Am far from your recommendations.... Any suggest? Cheers!! Keep it, good work

[@drunkmunkey6969]

All settings are very lean, except the needle... which is very rich. Maybe things need to ‘meet in the middle’? Do come down on the needle, and go up on everything else until it smooths out.

[@paulgregory39]

Hi, I have a PHBH 28 on my bike and often find the tick over is hanging and won't settle down, I have tried adjusting the mixture screw but it does nothing, do you have any ideas. Thanks in advance.

[@PeteScholes]

Great vids Dan just found them newbie bit of advice got a mk1 p125x been fitted with a 150 top end and a simonini exhaust looking at the 28mm pbhb dellorto is it worth it will it make a difference cheers

[@joshhyde898]

Hello I got a dave webster suzuki 190 with a JL pipe with a 28 delly, what would a rough jet be. Av266 x13 40 slide 55 pilot and 125 main?

[@drunkmunkey6969]

That's a good starting point from which you can road-test and plug chop.

[@chrisdickinson310]

hi Dan. Enjoyed the Dell vids. Great info. Can’t find my notebook so not sure what I’ve got in there but may as well ask you. Running a 225 Race Rapido, out of the box but with a MB shortie reed, 60 stroke crank with std rod. Piston cut for reed but no boost port. TSR Evo pipe And a 28 phbh. couldn’t get it anything like until I fitted the reed if feels ok but be interested to hear if you’ve a spec. Many thanks

[@drunkmunkey6969]

Best starting point is as stated in video. 55p, X13 (2nd), AV266, 300tap, 40 slide. With having reed, but no boost port, it’s a bit more peculiar. But start with a 130-135 and see how you go. Do plug chops from there on all throttle positions, adjust as you go 👍

[@chrisdickinson310]

@@drunkmunkey6969 cheers for that. If my memory serves and I didn’t fiddle about with it I think that’s where abouts I’m at with a 132 main... which was an uneducated guess. Cheers Dan!

[@maxalwaysgoesbyboat7366]

Ok i feel like im getting my fortune told...here we go...lambretta li 125 series 3 RT 195 kit .7 packer squish 1.14 PBHL 25mm standard jetting...107x58 crank...16 front teeth 81 iwis chain, 12v bgm ignition and afrayspeed 42mm clubman pipe just did dry build, checked off and hooked everything back...good spark, getting fuel no start... help? thx

[@drunkmunkey6969]

This may help: kzbin.info/www/bejne/jKPThGSMea18Z7M

[@BlackT5Scooter]

Opinion on air bellows to the frame for Vespas? Should be the best off both worlds for keeping debris out and not strangled with a filter. Have you tested this on the Dyno and how does it effect jetting?

[@drunkmunkey6969]

For a standard carb, yes, keep the bellows. 👍

[@BlackT5Scooter]

@@drunkmunkey6969 What about with carbs like the PHBH?

[@deanoldfield6877]

Hi Dan, I have a PX125 (1987) with Malossi 177 MHR kit, ported casing, PM tuning exhaust and Dellorto 28mm PHBH, 55 pilot, AV264, 122 Main, X2 (second clip), standard float/needle, and 40mm slide. The bike has just been rebuilt and has a Vespatronic @ 18 deg, but just doesnt feel very responsive and a bit lumpy as power comes on. Does the carb setup sound right? ive still got the mixture screw at 1.5 turns and the plug seems a healthy colour at the moment, although Ive only just had it out on the road for a short run , so difficult to say. Your advice would be much appreciated :-) All the best Dean

[@drunkmunkey6969]

Rotary pad intact or reed-valve converted? Cut/race crank or standard? Filtered or open mouth? Those things will make a difference to the answer you seek, and nothing other than accurate plug cops (or a dyno) will provide the info for certain, but my best estimate is that the X2 is slightly too rich in your mid-range and your main jet is slightly too lean on your top end.

[@deanoldfield6877]

@@drunkmunkey6969 Standard crank, no reed valve, but rotary pad opened up a bit as per malossi instructions, no air filter. Will take a look at a different needle and main jet if you could recommend where to start! thanks again, Dean

[@drunkmunkey6969]

Dean Oldfield start with 128 and plug chop from there

[@timc7270]

Hi I have a yamaha dt125 an fitted a phbh 28 to it would you know a good starting point for jetting thanks

[@christhefishman]

Hi I'm after some advice I have a lambretta gp200 stage 4 and a 30mm dellorto and sterling exhaust the carb has a 45 slide in it 70 choke 55 pilot and 130 main I'm having problems with cold start I have now put a 85 choke and 58 pilot in it and its starts a bit better now is this because of the 45 slide thanks

[@66almas]

Im building an old school suzuki 190 Using 65 mm mitaka piston barrel is a AF st 4 iron barrel iv had for years 60 x110 crank 28mm delly with eIther AF big bore or bgm v4 as i have both which do you recommend and any advise on jetting or start with your basic no filte , r just a tea strainer

[@drunkmunkey6969]

Start with the base settings from the video, with a 122 main and adjust from there with plug chops. Checkout our four-part Clubman Test series to help choose the best pipe for you: www.scootering.com/scootering-classics-lambretta-clubman-dyno-test-series-part-1/

[@kevinchamberlain7928]

What's a good economical, punchy, reliable, barrel kit to go with this carb, please? PX200E

[@stuarttiainen5433]

Have you set out up on a BFA306 yet Dan? Do you think they'd be too restrictive?

[@michaelchum]

Hi Dan, I just build up a pinasco 251cc Vespa Reed value with PHBH 28 carb and pinasco 251 box exhaust. What sort of idle jet, main jet, needle and value that I need to be go with?

[@alexandercajko700]

Hi Dan, thank you for the video! Very helpful! I was listening to get ideas on small block kits. I want crazy fast city acceleration: RT195 reed, RB20 or Imola? What do you think?

[@drunkmunkey6969]

Either RB20 or Imola on JL race pipe

[@alexandercajko700]

The Scooter Factory Many Thanks!

[@trianedtog0417]

@@drunkmunkey6969 alright dan I have an aprilia rs125 and looking at putting it back original i have got chance of 2 28mm phbh carbs which same as mine standard these carbs are off a honda nsr125 with die cast float bowl are all the carbs jets the same i know i will have to do plug chops 120 main jet my aprilia rs125 full power standard jetting is and needle is x2 middle notch thanks Paul hull i am terminally ill and do you know anyone who lives near hull Yorkshire for an hours work i will pay good money my email address is [e-mail] thanks Paul

[@drunkmunkey6969]

@@trianedtog0417 not sure about Hull, but i can tell you that Darrell Taylor in Doncaster knows quite a bit about the RS125 carb setups, I'd defo give him a call and explain what it is you need. Good luck bud.

[@ericwalker2172]

Hi Dan first of all thanks for making these videos I love to watch them, I have a RT195 in my TV and a 225 kit in my SX 200 in your previous vids you say use a 266 atomiser now in this vid you have recommended to use a 264 in both so it’s a bit confusing for me ,what do you think 🤔🤔

[@mooe1111]

Hi does this tutorial work for all two-stroke engines i.e. Rotax 122 Engines

[@drunkmunkey6969]

This tutorial is specific to Lambretta & Vespa scooters.

[@MrZikoHart]

Hi Dan I have a198 mugello kit with 28 dellorto a scootopia clubman exhaust could ya give me base setting for this , I live in Australia in warm climate Queensland.much appreciated thanks

[@raymercado8091]

Hola Dan, what do you mean by a reed valve?

[@solesust]

If you could do a quick viddi on a Gran Turismo gt 200 top end with a phbh 28mm deli. That would help me out.

[@peteryork321]

hi dan could you please give me a guide to jetting my carb, i have a phbl 26, 225 rapido classic and either a scoots rs pipe, or 42mm uni clubman, any advice would be welcome thank you

[@markbaker8894]

Fuel pumps are a definite requirement for a vespa long range tank, best fitted on the base of the tank, with the take off from the crank case.

[@stevebgp200]

RB20 engine what float would you be using? Running at the moment 270 Float - 147 main

[@seanlee74]

Brilliant content. How do these setting relate to a my 28mm carb? I've got a T5 running mollossi 172 kit ported and Harry Barlow crank and revolver exhaust. Currently has a 50 pilot 130 main but it's bogging down very low revs. Driving me mental 😂. Any help 👌

[@drunkmunkey6969]

Pipe? Atomiser? Needle? Clip? Slide? Filter?

[@adiehorrocks902]

Great video Dan, thanks for doing this series, Adie from green light scooters 👍🛵🚀

[@rs500sapphirecosworth4]

TS1 225 , 30mm phbh , Franspeed super tourer , open inlet , 145 main ?

[@pdenman7781]

Gt 185 clubman exhaust ,30mm phbh what jetting for this please .

[@drunkmunkey6969]

As per the video... start with 55p, AV266, X13 (2nd clip), 40 slide, 120-125 main, and then do plug chops from there, in order to fine tune to your specific machine.

[@olpallix]

Hi Dan?Do you still do this work? Where are you based? If not I was looking at dumping at Roger pro design or jb tuning. Any preference? I need 4 scoots doing. M210, 2x mhr135 and a wideframe pinasco on a 160pinasco. All got bells and whistles to go with em. Cheers

[@drunkmunkey6969]

Hi bud, no I’m full time at Scootering Magazine now I’m afraid.

[@olpallix]

@@drunkmunkey6969 That’s a shame. Cheers Dan. Loving all your vids!! Sincerely!!! Any recommendations on dynos? I’m in south London. The m210 is vibrating more than I’d like. I’m gonna change the x7 to a x13. 55 pilot 70 choke 40 slide. Not sure on atomiser. And go down on main jet 145 to 130. Transfers have been welded and opened on a Gori gp. Power is there but only in the high revs. Low revs it chugs horribly along.

[@drunkmunkey6969]

I wouldn’t just jump from 145 to 130... progress in small steps with plug chops. Also, chugging from carb and vibration are two separate things... vibration is usually related to engine mounts and/or cranks.

[@maxalwaysgoesbyboat7715]

OKAY SO HERES WHERE IM AT...lambretta series 3 125 with BGM 195RT, sip crank 107X58, scootopia 12v flywheel kit, af RAYSPEED 42MM CLUBMAN PIPE dellorto 25mm PHBL W 100 MAIN 53 PILOT D22 NEEDLE AT 1 CLIPPOSITION (TOP) STOCK FLOAT VALVE ATOMISER STOCK WITH STANDARD AIRBOX DRILLED OUT SO WHATS MY PROBLEM? my spark is wet, wet wet...I can get an ok idle for a minute but soon dies...i pull plug and its wet timing is right HELP!!!! THX MATE

[@drunkmunkey6969]

Check floats aren’t perforated/leaking, then check size of atomiser. You probably only want a 264 on that setup but with needle on a richer setting. Check timing with strobe gun.

[@paulwaite9123]

On my SIL GP200 engine, I've sort of followed Darrels bang for buck article, but left the ports as they were as they gave reasonable results. My carb is the scootopia 22, with Ram air filter (after your part 2, may ditch foam filter, keep rubber U tube and jet accordingly) and exhaust is scootopia clubman. So far, the MJ is 150 and 55 pilot and while running in it feels good, but I would say MJ probably needs to be higher. (I know Darrell ended up with 170MJ, but more tuned ports. However, 150 plus MJ on a 22 carb does seem illogical, or is that OK. Or to get a better balance of my engine parts, would I be better with a 25 or 26 Dellorto?

[@drunkmunkey6969]

If you are happy with performance keep the 22. The important thing is to get it jetted right. Never assume a jet is too big, unless you have evidence (Dyno, or plug chops, or bogging throttle etc). So go as rich as you can, and then lean off as you go. The cost of a handful of jets and a few runs up the road is far cheaper than a new piston :)

[@markjohn4986]

What atomiser Avanti , all you said was AV26 ?

[@drunkmunkey6969]

AV266

[@inicialracing9823]

Helow.. help help.. my config MBK51 AV10 Eurocilindro 72.5cc Reed Valve malossi Pipe malossi 21mm Manivela doppler RACING Exhaus ninja G3 Carburetor phbg ds 21mm. Config do carb. Low 45 .choke 60 slide 50 main jet 90 needle w16 😭 is my problem . I need w7?

[@wayneb251]

Nice end to the trilogy. Hopefully not too many holed pistons or seizures too follow, where information's been taken too literally and not as supplementary to existing knowledge. BtW - My MB240RV Cast made 23bhp running a 30mm PHBH and a Dev-Tour 👍

[@drunkmunkey6969]

Yup, these are basic guidelines to help get people to a meaningful starting point from which they can start testing and plug chops 👍

[@fredbert4048]

looking for a dyno and help Lancashire .b burn ..parmkit ignition 177 polini rebored ported polini race crank...scorpion pipe 28m delly .....i have perhaps 4 5 years riding left due to a spine defect ..want it spot on ...if possible ..i dont know anyone who will tune with dyno

[@ianboardman531]

Would this jetting be the same for a 28mm phbh??

[@drunkmunkey6969]

Largely similar, yes. Perhaps a couple of leaner tweaks in the end, but always start rich and lean of gradually until it cleans up.

[@exsoulagent]

What you should have said was 120-125 main jet and not Pilot @ 22:20😉

[@drunkmunkey6969]

Yup, I added a note in the description ;)

[@carlastew1]

Shuda wuda cuda !

[@ericwalker2172]

O

[@TheSteelweasel]

so out of the box is useless for 99% of scooterists . i dont buy a carb and then replace 80% of it .... thats insane ....... not for me sorry buddy .....

[@drunkmunkey6969]

Each to their own. It’s not for everyone 👍

[@davidtaylor9492]

What would you suggest then Steve

[@TheSteelweasel]

@@davidtaylor9492 unfortunately I have a bias opinion and hate delorto with a passion . I only use kiehin carburettors The reason is after using Amel in the 80s then delorto then mikuni I finally found a carb that performs well gives good fuel economy and made by a company that out sells all other brands by a long way in fact it is use by every major motorcycle manufacturer in the world including Italian companies. So its world no1 in carburettor technology and is constantly researching and developing.

[@davidtaylor9492]

Thanks Steve, interesting

[@munntoon]

I've a vespa 50 special on a malossi 136 with a 108. It's spluttering in high revs. Any ideas? We've no Dyno close to me. 😔

[@munntoon]

108 main. Nk exhaust