Polini CP 19mm carburetor, Any Body Using Them?

I am looking at getting a 19mm carb for my Peugeot TSM. I know most people are using the PHBG but this polini carb looks like it could be a contender.

My issue is that I can't find anybody who is using it on this forum and there isn't much info out there on tuning it that I have come across such as a factory tuning /setup guide.

Being that it is a multi circuit carb I am sure it is pretty similar to the dellorto in it's setup. The other issue is that I only see main jets available for it so no ability to run different needles floats or slides?

If you have used this carb or have any useful links pertaining to it hook me up.

link to carb on treats, https://www.treatland.tv/polini-CP-19mm-carburetor-complete-fuel-system-p/fuel-system-cp-177.0011.htm

Re: Polini CP 19mm carburetor, Any Body Using Them?

They look to be state of the art type of carbs. I plan on getting one after learning how to tune on a Bing first

Re: Polini CP 19mm carburetor, Any Body Using Them?

If im not mistaken they are just better copies of the kehein carb.

Re: Polini CP 19mm carburetor, Any Body Using Them?

NEMA Victor (3 Knees Down) /

I've got a CP 21mm, same difference really. I've noticed a few differences than the PHBG (which I swear by):

1) Turning out the fuel mix screw makes it leaner (not richer like the PHBG)

2) Where a 95ish jet is for a PHBG, it is a 83ish on the CP (for a 50cc 10k+ rpm setup)

3) Dunno wtf the black retainer piece is for inside of the carb (I left it on)

4) All aluminium body, lots of o-rings instead of gaskets. Lighter and better.

5) Very, very nice pull choke. Way better than the PHBG in my opinion.

You can always look at Polini's own document on it http://www.polini.com/en/page_696.html

My personal opinion is only left to the few days I've ridden with it installed. First impressions are they have a lot of technology for something so simple. That isn't to say it is a bad carb, it's to say, there are a lot of things that could make tuning go wrong: lots of jets inside the carb and on the venturi, weird overflow valves, etc. For racing, sure, you might need that, but not really on a daily.

Downsides to the carb are that it's not a flat slide, bit more difficult to find jets/slides/parts, screws strip easily and require loctite for the more vibrating engines. You'll also want to polish the venturi to a mirror shine since it isn't smooth out of the box (a good practice to do to any carb in any case).

I won't tell you to stay away from the carb, but I will tell you the PHBG is much more well documented and predictable in terms of what it will do if you change something.

Re: Polini CP 19mm carburetor, Any Body Using Them?

Ahh, thanks for the info Desert, I hadn't seen the link to the tuning page for that polini. I ended up just ordering another 19mm phbg as that is what I am used top and have all the jets already.

Re: Polini CP 19mm carburetor, Any Body Using Them?

I am curious about the carb as well. I was planning on getting a 17.5mm for my vespa DEPS engine. How does running at less than WOT work. I have been getting a bit of 4 stoking at half throttle that has left a small bogging when I take off from a stop with my dellorto.

Re: Polini CP 19mm carburetor, Any Body Using Them?

campeona del mundo /

i have a 17.5mm that ive been rocking for almost a year now..bought it right when they showed up at treats. ripped it on a 44 airsal on za and it felt great.

now i have it on a ported kstar, treat pipe, lightened 2 shoe, lightened main gear, clutch bell, plate, etc. and its amazing.

ive noticed that the air mixture screw is SUPER sensitive, really lets you dial in 1/8th throttle range. mains run relatively low.

definitely looking forward to running the 17.5 on a 50cc ripper moby

Re: Polini CP 19mm carburetor, Any Body Using Them?

i’m getting he 21mm to use ona yam G7s and on the FS1E i’m building.

Re: Polini CP 19mm carburetor, Any Body Using Them?

cool that this thread got bumped, i bought a 19, used, for a song a few months back. was going to put it on my polini puch but i ended up throwing on a PHBG instead... still not sure what i'm going to use it for, but i'll think of something.

Re: Polini CP 19mm carburetor, Any Body Using Them?

I've got a 19 on my race bike. Facing forward, minarelli v1 with a polini kit.

Works great for my bike on the track, always full throttle, but my bike isn't set up for street riding, meaning it sucks for low to mid cruising. Wants to load up and four stroke if cruising at 30.

Had to down jet the main, think I'm at a 70.

Spits out more fuel from the wide open, yet short, mouth, compared to the tube-shaped mikuni throat.

Big improvement compared to the 18 mikuni vm I was running.

Super simple, well built carb. And lightweight. Hasn't gone out of tune.

And I wouldn't polish the inlet. It's rough for a reason. Polini knows what they're doing.

Re: Polini CP 19mm carburetor, Any Body Using Them?

DrGeorgeTompson (Alan) /

I've run a 21 CP on 3 different bikes now. It's super easy to get working but i kind of like the PHBG because it throws a fit if some part is not tuned right.

There aren't a ton of swapable parts available for the CP either. There's like one richer slide and one richer needle.

Idk i'd still buy another. Probably because i have a ton of jets

Re: Polini CP 19mm carburetor, Any Body Using Them?

Some recent data points on the Polini CP 19 carb.

Been running it on a Puch with 70cc Treats kit (no reeds, no porting), case matched, Techno Estoril pipe, 82 main, 32 idle, leanest position on needle.

As someone else noted, spits fuel from intake. Haven't been able to run any kind of filter as it seems to plug up and kill engine. Runs great though with just the rubber angled adapter from the Polini 30 deg. filter (kind of a velocity stack). Previously running 15 Bing w/78 main. Similar speeds, Bing may have been slightly faster with corresponding higher rpm. Polini pulls way better in low and middle ranges and up hills. Also burns more fuel, but kind of expected that. Starts easily and idles well. Normal temps low 300's, highest 368 so far. Pretty happy with the performance overall.

Re: Polini CP 19mm carburetor, Any Body Using Them?

Make sure you guys running piston port setups have a closed air jet.

Re: Polini CP 19mm carburetor, Any Body Using Them?

Daniel, would you care to elaborate on the closed air jet thing? I'm not sure I understand exactly what it's for, but it appears to bleed more air into the mix at lower throttle settings. Just wondering why that might affect a piston port setup differently? Mine came with the closed air jet, but was considering experimenting with the perforated one.

Still seems like I might be running a bit rich across the board, and can't find any more options on needles or jets to lean things out. Don't expect it would affect WOT much, but perhaps might lean out the low end some? I should be able to up jet and/or move the needle richer to compensate if necessary, no?

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