Hawk X 250 jetting, and possible air filter and exhaust recommendations

[Hellenic]

Good morning, and thanks for having me as a part of your awesome community!

I have a brand new Hawk X 250 coming to me this week, and I've done as much research as possible scouring these forums but I was wondering if I could get some of you experts to provide me some individual guidances and recommendations!

I've been riding about 20 years, and have other bikes and plan to keep this one indefinitely.

I'm ordering a pe28 Nibbi carburetor, the flange model, in black, but two things I've noticed. Is one it's nearly $15 cheaper to get the non black finish model, is there any difference?

I can also spend only a few dollars more and get the version with the air pod filter. I plan to ride 90% street and 10% very light hard pack trails. Is it worth doing an air box delete and going to a pod filter? I'm not opposed to switching to it immediately especially since it's a good deal, but I'm not sure of the benefit.

This also applies to an exhaust, I've debated on ordering a JFG or Crf230 exhaust and running it right out of the gate. But the same thing, is there a huge benefit? Would you guys do one or both of them from the start?

My main question that I would help on, is im familiar with how to work on carbs, what jet does what etc, but I was wondering if anyone has any starter guidance for the jets.

For the next few months here it'll be 85-100f, and I live at sea level, I'm right by the ocean. What jets would you recommend I start with for a base line? If I went just air pod no exhaust, what jets would you recommend? What about airpod and exhaust with the pe28, what jets would you recommend for that?

Edit: I ended up buying the black finish PE28 with the pod air filter and a JFG exhaust. I'd still appreciate tuning recommendations for 90f and sea level

I'm sorry for the large post, but I really respect y'all's help, guidance and what this forum is.

I look forward to being a part of the community.

Thanks

Hellenic

[Bill Hilly]

Originally Posted by Hellenic

Good morning, and thanks for having me as a part of your awesome community!

I have a brand new Hawk X 250 coming to me this week, and I've done as much research as possible scouring these forums but I was wondering if I could get some of you experts to provide me some individual guidances and recommendations!

I've been riding about 20 years, and have other bikes and plan to keep this one indefinitely.

I'm ordering a pe28 Nibbi carburetor, the flange model, in black, but two things I've noticed. Is one it's nearly $15 cheaper to get the non black finish model, is there any difference?

I can also spend only a few dollars more and get the version with the air pod filter. I plan to ride 90% street and 10% very light hard pack trails. Is it worth doing an air box delete and going to a pod filter? I'm not opposed to switching to it immediately especially since it's a good deal, but I'm not sure of the benefit.

This also applies to an exhaust, I've debated on ordering a JFG or Crf230 exhaust and running it right out of the gate. But the same thing, is there a huge benefit? Would you guys do one or both of them from the start?

My main question that I would help on, is im familiar with how to work on carbs, what jet does what etc, but I was wondering if anyone has any starter guidance for the jets.

For the next few months here it'll be 85-100f, and I live at sea level, I'm right by the ocean. What jets would you recommend I start with for a base line? If I went just air pod no exhaust, what jets would you recommend? What about airpod and exhaust with the pe28, what jets would you recommend for that?

I'm sorry for the large post, but I really respect y'all's help, guidance and what this forum is.

I look forward to being a part of the community.

Thanks

Hellenic

The aftermarket exhaust that everyone uses, including the JFG ,are all technically for the CRF230, at your elevation, I would say about a 115 main, and 38 pilot, if you run aftermarket exhaust, and pod filter. Getting rid of the exhaust restriction is more important than just put on a pod filter, but if you do just install a pod filter with stock exhaust, then probably about a 110 main. The more expensive black carb won't perform any better than the bare metal one. The main advantage of the Nibbi, is availability of pilot jets, and easily accessible mixture screw. The VM26 "Mikuni " style, and the stock carb will easily flow all a stock, or even fairly hot motor will draw. You can also remove the catalytic converter from the stock exhaust.

[ProDigit]

Just get a PZ30 with included pod filter and fuel lines. They go for like $30, and just as good as a Nibbi.

The PZ30 I ordered, came with a 38 pilot and a 108 main, and was pretty spot on for my Vader 150. Just needed to add a bit of fuel with the AF screw.

You likely will need a 110 main.

The problem with the stock airbox you currently have, is
1: that it's in the way of swapping out the carburetor easily,
and 2: the hose connecting the carburetor to the airbox is made out of flexible rubber. This means at times it will cause a restriction.

If you ride your bike in rain or puddles, there may be a way to install your carburetor and PID filter, and drill a hole in the airbox, and fit the pod filter inside the airbox, preventing mud or water splashes to dirty the filter.

However, for street riding or mild rain, the pod filter is good enough by itself.

[red2003]

Yes, there IS a difference between the black and natural finish Nibbi's. I have both models of the PE28 flanged carbs. The natural finish carb is not a polished bore. It's especially noticeable on the air intake side. Does this actually make a HP difference? Dunno. The 2 carbs have tuned VERY differently. I am running both of these carbs on OHC engines, but the general rules should still apply to the pushrod Hawk engine. The black polished bore Nibbi ended up with a 40 pilot, needle raised to clip position 4, 130 main, and air screw 1 1/2. I tried these same settings on the natural finish and it was so lean it would hardly run. I am currently at 40 pilot, needle raised all the way up to clip position 5, 155 main, and only 3/4 turn out on the air screw. This is a decent tune, but STILL on the lean side of correct.

So, the two carbs are, in fact, VERY DIFFERENT, even though they are both Nibbi PE 28s.

[Hellenic]

Originally Posted by Bill Hilly

The aftermarket exhaust that everyone uses, including the JFG ,are all technically for the CRF230, at your elevation, I would say about a 115 main, and 38 pilot, if you run aftermarket exhaust, and pod filter. Getting rid of the exhaust restriction is more important than just put on a pod filter, but if you do just install a pod filter with stock exhaust, then probably about a 110 main. The more expensive black carb won't perform any better than the bare metal one. The main advantage of the Nibbi, is availability of pilot jets, and easily accessible mixture screw. The VM26 "Mikuni " style, and the stock carb will easily flow all a stock, or even fairly hot motor will draw. You can also remove the catalytic converter from the stock exhaust.

Originally Posted by ProDigit

Just get a PZ30 with included pod filter and fuel lines. They go for like $30, and just as good as a Nibbi.

The PZ30 I ordered, came with a 38 pilot and a 108 main, and was pretty spot on for my Vader 150. Just needed to add a bit of fuel with the AF screw.

You likely will need a 110 main.

The problem with the stock airbox you currently have, is
1: that it's in the way of swapping out the carburetor easily,
and 2: the hose connecting the carburetor to the airbox is made out of flexible rubber. This means at times it will cause a restriction.

If you ride your bike in rain or puddles, there may be a way to install your carburetor and PID filter, and drill a hole in the airbox, and fit the pod filter inside the airbox, preventing mud or water splashes to dirty the filter.

However, for street riding or mild rain, the pod filter is good enough by itself.

Thanks for the info guys, I ended up buying the black finish PE28 and a PJG exhaust. I will take your advice on the jet sizes for the pod and exhaust

Originally Posted by red2003

Yes, there IS a difference between the black and natural finish Nibbi's. I have both models of the PE28 flanged carbs. The natural finish carb is not a polished bore. It's especially noticeable on the air intake side. Does this actually make a HP difference? Dunno. The 2 carbs have tuned VERY differently. I am running both of these carbs on OHC engines, but the general rules should still apply to the pushrod Hawk engine. The black polished bore Nibbi ended up with a 40 pilot, needle raised to clip position 4, 130 main, and air screw 1 1/2. I tried these same settings on the natural finish and it was so lean it would hardly run. I am currently at 40 pilot, needle raised all the way up to clip position 5, 155 main, and only 3/4 turn out on the air screw. This is a decent tune, but STILL on the lean side of correct.

So, the two carbs are, in fact, VERY DIFFERENT, even though they are both Nibbi PE 28s.

Thanks! Very glad I made this post. I ended up ordering the black finish, definitely seems worth the extra few bucks. Especially since I want to do a pod filter to save a few ounces

[red2003]

Originally Posted by Hellenic

Thanks for the info guys, I ended up buying the black finish PE28 and a PJG exhaust. I will take your advice on the jet sizes for the pod and exhaust



Thanks! Very glad I made this post. I ended up ordering the black finish, definitely seems worth the extra few bucks. Especially since I want to do a pod filter to save a few ounces

I am at 900 feet and in a relatively cool climate, btw. The Nibbi only comes with 110, 112, and 115 main jets. I would be surprised if you don't need something bigger, FYI. They take Keihin short main jets, same as the PZ30.

[Bill Hilly]

I'm on my second bare metal Nibbi, and they have both had polished bores, like a mirror finish, but either of them will flow more than what your likely to make with a CG. Dan has what sounds like a 20 HP, or a little better build on his , and the last I heard he was running a VM26, Mikuni style. Until yesterday, I had what I assume was pretty close to a 19, or 20 HP build, and I was running a Nibbi PEZ, but I'm putting a stock motor on the bike for now, because I lost the bearings from a cam follower, and it damaged my timing gears, and probably cam as well. The motor I'm using has a VM26 Mikuni style, and that's what I'm planning on using. The only real drawback to those are the fact that the mixture is hard to reach, like on the stock carbs