Nibbi PE28FL
 

Yep, trying yet another new carb on my Hawk. But this time, I think I will have found the happy middle ground.

When I swapped the PZ30B back on my bike, I could tell I lost a little power up top. Not a ton, but it felt a little held back. What I liked was the better state of tune, idle, and less sensitive nature of the carburetor when the climate changed. It also fit better all around, IE the throttle cable wasn't getting presse into the tank and being kinked over.

What I loved about the PE30 was how easy it was to tune things like the idle mixture, the idle speed, and the responsive nature.

I came across this flanged PE28. https://www.amazon.com/dp/B09KXTVTGR...roduct_details

It will flow better than the PZ30. But being 28mm should maintain better velocity than the PE30, and it bolts up to the stock style intake, so fitment issues will be a thing of the past.

I have even considered ordering a TT250 airbox and making an intake tube to run an airbox again, modified slightly with a pod filter inside. But that is for another day.

The only real challenge I have now is just having the time to install and tune it as I am taking some classes on my off days, so I have little free time to work with.

Thanks Dan! I just added that one to my wish list. Like I need more to do. lol I think that will be the perfect carb for these bikes. I like that it has the flange mount.

No doubt! That flange mount is a game changer!

Always glad to help fuel addictions that I share with people lol.

I agree though, I think these are probably the best matched carb for a CG250. total area of the 28mm bore is still larger than the PZ30 venturi, and without the choke plate and venturi it will definitely flow more air and with less turbulence. All without the velocity drop of the PE30, which I think is a bit wasted without a higher lift cam and/or the CG300 cylinder.

Best of all is the fact that it uses the stock style intakes, which means it eliminates all of the fitment issues I have had with the socket style carbs on my bike.

Also, if you don't mind having just a regular silver carburetor they also sell one in a more natural finish and its about 14 bucks less.
https://www.amazon.com/dp/B0925SM1S4...NsaWNrPXRydWU=

The nice thing is, I have even found a little jetting information for a CG motor, and from what I can tell it's well within the same jetting as the PZ30, so I should be close just swapping over my PZ30 jetting to this carb.

I put a PE 28 on my HAWK last fall. I could not believe the manifold issues. I must have bought 6 manifolds and none of them would work. This carburetor would have made it easy peasy. NIBBI got smart or maybe that was a production carb they offered up to all.

Thanks Dan,

Fitment issues with an intake manifold are what have kept me from using a Nibbi thus far. Now, problem solved!

close quarters-room for the Nibbi Carburetor
 

I have this stupid rule of spending as little as possible on the bike. I had to get tires and jets, but I like the idea of knowing how little I had to spend to have such a great bike...This might be an exception;) It looks good Dan.

The old goofy flange adapter for the hose/clamp mounting style NIBBI carb interface takes a few inches and places the carburetor far from the engine, likely causing direct carb contact with the frame tube, and pushing the carb off center... Based on what I've seen, the carb doesn't fit straight on the hose on a Brozz 250, probably most/all CG engine clone full size dirt bikes we discuss here. It is not only crooked on the hose, but also the float bowl is cockeyed. Having a straight through air path and a nearly level float bowl must have an impact on performance!

So this new flange mount on the PE28FL is not only an ease of installation improvement, but it will mount right.

From what I have seen in videos, the NIBBI PE series seem to have the pilot and main jets in the same position in the carb body as the PZ30. But I DON"T see a pilot adjustment screw:hmm:

And exactly what is that choke plunger doing down in there? I wonder how that works for enrichment. One of those side ports? Well, no butterfly valve for choke is definitely better for smoother air flow through the carb body. That's excellent.

The big knurled wheel on the slide column will make idle adjustment EASY (slide height)! That is nice. And it comes with a manual/setup guide. How unique:) Most clones arrive with no documentation (after all...doesn't everyone already know how to jet/adjust a carb, well, no!)

I think the NIBBI takes a Keihin needle so you can select different tapers, and set needle with the circlamp and fine adjust with washers (NICE!).

The idle mixture screw is just to the left of the idle speed screw. The idle mixture screw is for air vs fuel that's on the PZ30 so keep that in mind when tuning.

had a PE26FL in my cart for too long and missed it. Kinda bummed, I'm betting it will be a while before I see them in stock again. Really do not want to have to use a rubber flange with the regular PE26.
Carb/intake space is kind of a premium on my smaller bike. Not to mention dicking with getting the manifold to fit right. Its a Z20 max with an actual airbox.

The fitment issues were honestly the most frustrating part. I was getting to the point of wanting to 3d print an adapter for a straight socket, but even that would have had issues unless I angled it right. Then there was always the potential issues of long term degradation of fuel and heat on said plastic. I also probably bought 6 intakes trying to get other carbs to fit. The best one I came up with was the CQR intake, but it was also the longest of the bunch, so it positioned the carb far enough out to cause interference issues with the tank and throttle cable. I never could win.

As Jerry said, the idle mixture screw is on the side of the carb, and unlike the PWK carbs, the RIGHT side of the bike, so it is super easy to adjust. No more burning hands, special wonky tools, or having to remove the carburetor.

The choke plunger is just an enrichment circuit. You pull it open and the vacuum difference draws fuel up from the bowl. About as simple as it gets.

Yes, the big idle speed adjustment knob is the other great feature of this carb. That is one thing about the stock carb they got right too. It's easy to find with gloves on and no need to fiddle with a screwdriver.

The Nibbi carbs also do take Keihin needles if needed. I found the one in the PE30 actually worked ok so I never had to change it, but real PE needle options also work on these. These are higher quality clones.

Seems the fist link is currently unavailable.
Second link still has stock.

tried to find them on Ebay/Alixpress...no show.

Im tempted but they are $88 shipped to Australia...maybe I can justify signing up to prime again and save a bit on shipping.

The side enrichment screw for me is the key selling point. Also the fact the PZ30B didn't fit with my XL frame making it a non B to work and I'm kinda over the raised choke cable makes this flange Nibbi very appealing.

Kinda wish the red and black version was still in stock to match my bike.

Very tempting.

What are the thought regarding the PE28 and a CG300 cylinder...
I have preemptively ordered a 'big bore' while still available on alixpress.

I have a feeling a few guys here placed orders. The black one was low stock when I ordered it.

With the 300 cylinder the PE30 might work better, but the 28 would still be a good carb for it. Only a 21cc increase on a low flowing head.

Seems Amazon.au still have the red/black version in stock...

https://www.amazon.com.au/Motorcycle...=XUG0IMIV9ZNR&

Just ordered mine..hopefully the in stock indication is legit.

Whole lot of $140aud beans for a side screw enrichment and shiny knobs (performance improvements are noted)...but I still have the PZ30 as cg300 spare/backup if required.

Take it from me. The quality of the Nibbi carbs also justifies the extra beanage. They are that next step up.

The Carb has Arrived!
 

Delivery person dropped off my package today.

https://i.ibb.co/ySnF7z5/im-detectin...or-captain.jpg

So for the details on this carb.

It comes shipped with 2 gaskets, a thermal plastic spacer, 4 main jets and 2 pilot jets in total. The jet sizes are actually damn near spot on for a CG250 with basic bolt on mods.

I don't plan on using the spacer since the Hawk intake is partly insulated with rubber, but I do plan to keep it for a future gasket template.

Main Jet sizes are 108, 110, 112 (installed), and 115

Pilot Jet sizes are a 35 and a 40 (installed)

As far as I can tell everything else about this carburetor is the same as the PE30. Same slide, same needle. same basic carb body other than the flanged end, just a smaller bore. In theory if you really wanted to you could bore this carb out to a 30mm and create a flanged PE30. I just need a chance to compare the two side by side, but my assessment is pretty confident on that.

Honestly, the only real hiccup I see with this carb bolting up is the flange itself is a bit thicker than the PZ30 carburetor, so either longer studs will need to be installed, or the studs removed and appropriate length bolts used. If that is honestly the worst thing I have to deal with on this carburetor, it will be a blessing compared to the issues I had with the rest of them.

Pictures on Page 2. :tup:

Pictures.
 

A couple of quick shots of it, just because. These are reduced image size. Click the picture for a bigger picture if desired.

https://i.ibb.co/Dbx0hBP/PE28FL2.jpg


https://i.ibb.co/Yksgp5N/pe28fl.jpg


https://i.ibb.co/4YcF61m/PE28FL1.jpg


https://i.ibb.co/8488vMG/PE28FL3.jpg

I ordered one and an exhaust for my brozz. Thanks for the info ������������

Sweet! Share your pictures.and.impressions here as well as any tuning questions, final jetting, etc. It's nice to try and keep everything in one place for others to reference.

You will also need either a pod filter or to make a custom intake tube to your air box as well, so keep that in mind.

As far as jetting suggestions, the 35 pilot should do the trick, if not order a 38. The 40 in my experience is too big.

Main jet, I would start with the 115, which is likely close anyway. If you are near sea level a 118 or even a 120 might be worth having on hand as well.

Yeah I’m off work next week so that’s going to be my primary 1

Been running the Nibbi PE28 for about 7,000 miles now and love the carb. If they ever show up on sale I'll be picking up the flanged for sure. Glad Nibbi keeps making new stuff.

I am glad they are making new things as well. I noticed they now.have clutch and throttle cables with a middle length adjustment. Very tempted to order those and try them out.

This is the stock intake bolted up to the Nibbi flange finger tight.

https://i.ibb.co/G0VhTM3/PE28FL4.jpg


The original studs are just barely long enough that they should work. If you would like the stud to be longer, you would have to find a stud that is no more than 3mm longer than the original one though. The reason why simply has to do with the body of the carb where the enrichment plunger is housed will make contact otherwise.

The other option would be to switch to bolts.

In either case, the side pictured needs to be started first so that you can get the nut over the threads to start it. If you try to do it the other way around you can't clear the nut past the body of the carb for the same reason the longer stud can only be 3mm longer. Simply not enough room.

I am going to run the original studs and nuts with some thread locker on them and treat the intake and carb as one complete assembly. Since the space is so tight on that plunger side anyway it would be even more annoying to try and remove the carb that way. The intake bolts are much easier to access.

Mine came with a 112 main and 40 pilot installed. It came with 110,112,115,118 mains and a 38 and 40 pilots. So I’m going with 115/38. Sad part is I was removing the air box and grounded my starter solenoid on a bolt and started smoking the ground wire. I know my battery is smoked now. I even told myself to unhook the battery.

[IMG]https://i.postimg.cc/zVtjPDSp/A63-B0...-D6-BBF2-C.jpg[/IMG]

Exhaust will be here tomorrow and will go for a rip.

I'm curious. what's the tube protruding out the side, near the idle adjust knob do?

Interesting that we seem to have a couple different jet sizes mixed in. One main and one pilot jet being different lol. Oh well, for me it doesn't really matter, none of the mains are anywhere near big enough for my bike and I already have a 38 pilot if need be.

Sucks about the ground wire and the battery. I was replacing my stone dead battery anyway so I avoided this potential issue by default.


It's just a vent tube. The bowl vent is on that side, so they have the little downturn length of tube to act as a sort of barrier to keep dirt and such out. You see it a lot on mechanical slide carbs like these, sometimes having two.

I got her running. Started right up with the “choke” but wanted to stutter pretty bad and with it off. The mixture screw was 2.25 turns out so I turned that in over one turn and it cleared it up pretty well. I think I am still a little lean but she ripped pretty good and midrange was quite a bit more power. I am going to play with needle height and maybe primary jet.
[IMG]https://i.postimg.cc/T3vdq1qY/AE8989...1-AFCC3-BE.jpg[/IMG]

Oh and the exhaust is a “stoneman” exhaust off of Amazon. And I had to drill 2 new holes for the mounts and I had to slot one of the flange bolts.

I know on a stock CG250 the 35 pilot is just about perfect, maybe a Teeny tiny bit small, so the 38 being the same way with the exhaust sounds about right.

I am waiting for my throttle cable to get here before I can install mine. Le sigh.

That and our weather went back to trying to be winter again.

I put the 40 pilot jet back in and surprisingly about 1.25 turns out on the mixture screw. It’s really snappy now on the bottom end and is really close for cooler weather. So I’m at 115/40 and it’s running pretty good. I suspect I might have to play with it in the summer tho. But right now it’s pretty good, even kick starting pretty easily.

[IMG]https://i.postimg.cc/6Qb99sVT/D0-ECB...27-E23-B79.jpg[/IMG]
The carb comes with really good tuning instructions. This should be a sticky

I always thought screwing the mixture screw in made it leaner though

On a carb that has a fuel screw yes, but this is an air screw. In most carbs, if the screw is in the front of the carb and underneath, it will be a fuel screw. If it is at the back of the carb near the carb intake, it will be an air screw (i.e., it controls the amount of air allowed into the mixture, at least in a "fine-tuning" sense).

Dusman nailed it.

If the idle mixture screw is located before the bowl (inlet side of carb) like the PE carb then it controls how much air goes into the idle circuit. It quite literally just moves a rod that blocks a hole to meter air through a passage.

If the idle mixture screw is after the bowl like the PZ carb (outlet side) then it controls how much fuel is pulled through the circuit from the bowl. in essence it's a lot like the needle on the throttle slide, allowing more or less fuel through the passage based on how much the tip of the screw tip blocks the hole.

You probably wouldn't be too surprised to learn that a lot of people get this wrong when they switch to the PE carbs.

I got my throttle cable in today. Of course the high temp today is 38 degrees, so no tinkering for me today, or likely the rest of this week.

Since I have a quick turn throttle most of the standard cables you would use on these bikes are actually too short/housing too long. I noticed Nibbi had a throttle cable listed and the cable size seems to be just about right. It also has an adjuster in the middle of the sleeve like a proper cable should.

For the price I am impressed. Hopefully it holds up over time, which is usually the real test. My only complaint is that they don't have just a black cable, so I decided to stick with the unintentional theme of my bike and ordered red.
https://www.amazon.com/dp/B07R9RZR5Z...roduct_details

Looks orange in their picture, but it is indeed red.

I also decided that I had to keep the cables matching, so I went ahead and ordered the red clutch cable too. I can keep my original as a backup. https://www.amazon.com/dp/B07R8PP1T6...roduct_details

This cable also has an adjustment in the middle of the housing. That gives 3 adjustments on the clutch cable in total. A tad overkill, but hey, good to have options.

Mine will bog if I crack the throttle really quick. If I roll on the throttle it is good. I don’t have enough experience to know if that would be a lean or rich condition with the needle position? Playing with air screw doesn’t seem to make a lot of difference. It doesn’t bog at WOT so I assume that might be normal or maybe needle adjustment.

Very possible you are too rich on the transition from one jet to the needle. Mine came with the needle in the 4th notch. I always start off in the 3rd/middle position. On my PE30 I had similar issues, a slight stutter when rolling on quickly. I moved my needle clip to the 2nd position (from the top) to lean it out some and it was perfect after that.

Thanks

Got around to installing my PE28FL today. The nibbi throttle cable is actually too long. Not even a little too long, like every adjuster backed out of the threads and it still had a lot of slop too long. I am not exactly sure what the heck this cable is for, but I can't think of a single carburetor that could use it. I may actually buy a barrel, cut it, and shorten it to a useful length. It's a nice cable otherwise. Thankfully I did have a single pull cable from another throttle I bought that I forgot about and it worked out ok.

The clutch cable is too short for the stock Hawk holder to reach the lever arm. I am waiting for a CRF230F unit that bolts to the case further back to give that a try and see if it works. Necessary? No. Just another one of my tinkering experiments.

The carb installation itself - still having an issue with tank clearance and the throttle cable right at the top of the carburetor. I guess the nibbi is just tall and forward enough to hit in almost exactly the same place. At this point I am thinking I may just dent the damn fuel tank and be done with it.

It's not bad enough I couldn't get it mounted though, at least no worse than the PE30, and at least with the stock style intake there is a lot less intake flex/movement when riding.

Jetting I started with was essentially the jets right out of my PZ30B carb. The pilot is a 38, the Main is a size up at a 135 just to be safe. Idle mixture started at 2 turns out and I had to use the cold start enrichment to get it going. Once it idled for a few minutes I turned it in until I was 1 turn out and it started to stumble a bit. Backed off 1/2 a turn and it was much more stable, backed off another 1/4 turn and the idle holds dead steady at 1500. Hot restarts fire right back up. 2 turns out is just a wee bit lean on the idle, but still allows it to fall back to idle rpm without hanging up. I tend to like my idle a hair on the rich side with my compression being so high and my ignition advanced, so i am quite happy where it is.

I didn't get to check the main jet yet, but I suspect it will be fairly close. I did notice I get the same stumble transitioning to the needle like I used to get with the PE30 when I had it in the 3rd slot. I am going to simply move it to the second just like I did with that carb and be done with it.

You have probably already considered it in your analysis but sometimes those 90 degree cable carburetor inlets can help and they use more cable too.