Best size Carb for Hawk 250
 

Hello, I have recently bought a hawk 250. After learning about how poorly tuned these are from factory I started looking around YouTube for a new carburetor so I could properly jet the engine. I know many people go with the VM26 clones that have a weird hybrid 30-26mm barrel. I have seen a lot of people say they work great stock but can limit the engine when you want to upgrade and swap parts (especially once a better flowing exhaust and intake are installed). I have future plans to swap the exhaust and change to a pod filter so I didn't want to be limiting my top end with a smaller carb (also the very popular Hwbnde VM26 clone is out of stock on Amazon right now). I then did some research into the Nibbi Pe series. I know some people have used these on highly modified China bikes (Port/polish, compression changes etc). But I have not seen any information about then being used with stock or simple bolt on parts, so I am wondering what the best size Nibbi Pe carb would be for a hawk 250 with just bolt on parts like an exhaust and pod filter? I’ve looked at both the Pe30 (30mm) and Pe28 (28mm). I am wondering if the true 30mm barrel is to big for the hawk and will be hard to jet correctly? Has anyone run either of these on a stock bike and knows a little more about them? Any advice or information would help.

In my opinion the PE28 is the best choice to answer your question and will provide all the power the CG motor can make with most modifications. There might be other carburetors that are a better choice depending on your needs or desires such as the PZ30B. There is a lot of tuning for the PE30 (should work on PE28 but adjusted for your modifications or no) on the forum you just need to search for it. I have not run a PE28 or PE30 on a stock bike but I believe it is doable and the PE28 will help in that regard. Since you are planning mod, worst case you will need to open up the exhaust.

I have run the PZ30, PZ30B, VM26 (same as PZ30), PWK30, PE30.

THe 30mm smooth bores like the PWK30 and PE30 are definitely too big on a CG250 engine with just an intake and exhaust. With a ported head and cam they are still a tad on the big side, but do work better. They are still very finicky to get the jetting dialed in, and very sensitive to changes in atmospheric conditions. If you want an all out race bike with all of the engine work that goes with it, then a 30-32mm smooth bore is for you.

Otherwise, my suggestion is either a 28mm smooth bore such as the PWK or PE28. These will be the best balance between best power and rideability.

That being said, I have a ported head and cam and I went back to the PZ30B (pumper version of stock style carb) and I am quite happy with it. It may have given up half a HP or so on the very top end, but the low and mid range RPM and idle are strong and steady. Fuel mileage is also a lot better, even with the accelerator pump, over the 30mm smooth bores.

Megadan speaks words of wisdom! Let me not leave the wrong impression and provide a better reasoning. I may be overly optimistic suggesting a stock bike can run a PE28 let alone a PE30 but I would sure like to try tuning it! It has been awhile since my bikes have been stock. I will also agree, in my experience the PE series of carburetors are difficult to tune and therefore not the best choice for someone new to carburetors or desiring to have immediate stable results.

The general consensus from the TBR7 community (same carb setup as the hawk) is that the nibbi 28 is fine.. 30 is only needed for extreme mods. The mikuni clone works for just about everyone with stock or standard mods just fine.
https://tbr7.com/upgrades/fuel-system/

I concur with Dan as well (as I often do). I have a PE30 Nibbi on my Hawk now- having previously ran the HWBNDE vm26. I have basically every upgrade/mod except the CG300 cylinder and a cam (the camshaft is in my toolbox, awaiting install).

The PE28 would be a better size than the 30, even for me. The PE30 was a bear to tune.. but once I got it, I got it. And it definitely added to engine power. BUT... weather changes do affect it drastically.

My throttle response and general "rideability" were better with the vm26. It was smoother on and off the throttle. The PE30 feels like there is a detent off idle, and it is a very sudden "ON" feeling. You really have to know how to handle the throttle otherwise it's too much and you're popping the front end off or taking off too fast. Low speed throttle modulation is not good. For an all out race bike, it's perfect.

It's dialed in now... so I'll leave it. And the PE30 didn't cost me much as I traded a pre-tuned vm26 for it. BUT... if I were to know what I know and do it all over again, I'd either do the PZ30B pumper like @Megadan or just leave it with the VM26 clone.

carb upgrade
 

Hi, I am getting either the raven or hawk and want to know best carb upgrade. mods will be exhaust, unifilter. should i get a 28mm or 30mm. what jets for chicago, IL area?

thanks for your help in advance. appreciated

rocky mountain atv recommends 125 main and 45 pilot for the crf 230

So I don't have to type it all again

Those suggestions are for a very different bike and engine. Neither will work out well for you.

Pilot jet on a CG engine with a PE carb you are looking at a 35 or 38 in most instances.

Main jet with an exhaust and pod filter will likely be a 120 if you go with a PE28 - my suggestion if you just HAVE to have a PE carb. You will have to determine if that jet is the right one for you though based on density altitude.

Ive seen great results with the pz30 with a 125 main jet, did airbox delete , pod filter , cat delete. Really easy to tune