Project: Hawk Stage II - Head Work and Nibbi

Baskt_Case · 05-17-2020, 05:14 AM

The plan is to port (including matching) both intake and exhaust, polish the exhaust, mill down for compression bump, and install a Nibbi PE30.

I am using the "improved" Rato CGP head that is equipped on the Brozz and TT250, among others. I will be employing the use of A.P.E. Racing for my head work.

My project was conceived after exhaustive reading both here and elsewhere and was originally thrust into light in the Hawk 250 Enduro Owners Group on Facebook. I would like to share here as well, especially considering that the largest part of the technical knowledge required for this project has been gleaned from members and projects right here on Chinariders.

I would also like to share a highly inspirational article on serious CG performance:

How to set a land speed record on a $3,200 motorcycle.

Am I Bonneville bound? I'll never tell!

My current inventory of project parts...

Brozz Head and Gasket:
https://shop.brozz250.com/eshopprod_...r_Assembly.htm

OEM Style Gasket:
https://ebay.us/VnECnk

Nibbi PE30 Carburetor:
https://www.amazon.com/gp/aw/d/B07P2VY8NC

Nibbi Intake Adapter:
https://www.amazon.com/gp/aw/d/B07PCN9MQW

Generic 30mm CG Intake Adapter:
https://www.amazon.com/dp/B07JG3M1T5

Nibbi Pod Filter:
https://www.amazon.com/gp/aw/d/B07KQZMVF3

UNI Pod Filter:
https://www.amazon.com/gp/aw/d/B000N5UCEG

Jet Kit:
https://www.amazon.com/gp/aw/d/B077BVZVQZ

Other miscellaneous items still yet to be purchased for this project are fuel line, fuel filters, torque wrench, 16T sprocket, calipers, extra plugs for tuning, and filter oil.

Megadan · 05-17-2020, 08:56 AM

That's not an EGR port. Just so you know. That port is for the air injection. Not one of these bikes has EGR.

Glad that my own efforts have inspired you forward, as have those of JerryHawk250 and a couple others. That's the whole point of this forum.

Surprised you haven't looked into a camshaft as well. One of the biggest limitations to these CG engines making power is the camshaft. Once you go past 7500 rpm, the power delivery still falls off pretty quickly. Even my own bike will usually top out right at 8000rpm in 5th. Honestly, that "improved" head could probably make great use of the Ressalto cam profile I picked for my bike with just a little cleanup work.

In any case, I am subscribing to this thread. I look forward to the progress and your impressions of the results.

You should take a moment to install and get the PE30 running on the stock head just for a comparison. It would be nice to have an opinion of the PE30 without port work.

Baskt_Case · 05-17-2020, 11:59 AM

Thanks Dan, my blunder for perpetuating the EGR myth. It doesn't help that CSC specifies it as such in their own documentation, tutorials, and parts listings. Add that to the fact that alot of us in less restrictive parts of the country have never had the pleasure of physically dealing with an emissions equipped Chinabike.

Indeed, I would not be at my current point of progress in my endeavors without the prior countless hours of research, experimentation, and work performed by you and many others here on the forum. I am very grateful and only hope to expand the knowledge base, and have alot of fun doing it!

Ahh yes, the cam. I am eagerly following your thread for your results and impressions. It is definitely a possiblity for the future, perhaps a "Stage III" project. My plate is comfortably full at the moment with just the head and carb upgrade. However, I am definitely watching you closely, especially since you have started talking about a 32mm carb. Have you read the article from CCW that I linked above?

Upon my initial inspection of the CGP head, I was quite pleased with the factory port profiles compared to my stock head. Its not a massive difference, but plainly visible. Others have suggested the same as you, that just some touch-up work and matching alone would probably yield a significant improvement over my stock head. However, I am "committed" at this point, my heart is set on professional head work. I just wanna see where this goes. In regards to a future possible cam upgrade, heavier valve springs are definitely on the table with the builder.

Originally I was going to wait to install the carb simultaneously with the head but as you and one other individual have pointed out, it would be nice to quantify the gains of the carb and head separately. So carb installation will commence soon!

-Aaron

Megadan · 05-17-2020, 04:41 PM

Quote:

Originally Posted by Baskt_Case

Have you read the article from CCW that I linked above?

Yeah, I read it a couple of years ago. It's what actually inspired me to take it further with the head work, cam, and carb. I won't be trying to go 90mph, but I would love the added acceleration and some more high rpm power.

Baskt_Case · 05-19-2020, 12:35 AM

So today I was able to nail down specifics with the engine builder regarding exactly what work will be performed. I should have the head shipped out in the next day or two.

I will be using A.P.E. Racing in Rosamond, CA. These guys didn't even flinch when I said it was a CG motor. Communication with them has been nothing short of professional.

Disassemble, Clean, Inspect.
CNC Porting (plus match to my gaskets).
Polish on exhaust only.
Unshroud valves and address quench gap.
Multi-Angle Serdi Valve Job
- Bronze Guides
- Stainless Valves
- Heavy Duty Springs
- Titanium Retainers
Deck 0.8mm (.031").
Assemble and Flow Bench

$439 Shipped (both ways)

For comparison, they will sell you a brand new ready-to-race CRF250 head for $945 + Shipping.

China Rider 27 · 05-19-2020, 10:40 AM

I would want to get some objective and quantifiable performance measures of my motor to do a comparison of before and after. Dyno?

Megadan · 05-19-2020, 12:38 PM

You will definitely have the most prepped head of anybody on this site. That is race level stuff through and through and not the typical budget DIY job.

Megadan · 05-19-2020, 07:24 PM

A dyno would be the best way by far, but for many the access to one is either limited, or otherwise impossible. Only one in my city, and you have to book it 8-10 weeks in advance, and even then there is no guarantee of getting the day you scheduled because they don't run the dyno if the temps go above 90F outside, or below 50F.

What is kind of funny is the influx of bigger carb installs and ported heads as of late. My first year or so on this forum, the biggest and baddest mods people ever talked about was exhausts or decats, VM26 car clones, airbox mods or pod filters.

Then one day I post a thread about head porting after buying a head, then a couple other guys, ie Jerry, Silva, and at least one other I can't remember all decided it was a good idea too, and thus in a short span all of us had ported heads. Not one dyno.
No quantified results with a dyno or otherwise, just people taking our word for it, and the proof was in the pudding.

Then for a while, nobody else really dove in right away. Not sure if they were too afraid or what, but it stayed pretty mute.

Then Jerry installed his PWK carb, and not long after I installed me PE30. I made a couple of videos and posts here exclaiming "Holy Moly!" at the increase in power and torque across the entire rpm range. Up to that point I was running the PZ30B, and with the ported head it felt decently stronger than before, but the result felt about the same as installing the exhaust on the bike. A good increase, but nothing too outrageous on its own. Once I gave the head the air to actually breathe, it was a completely different story. Jerry posting similar results with his PWK carb.

Within a few months of us posting our results, a few more popped up here and there and they back up our own words, and thus a chain reaction. Now it almost seems like everybody with a chinabike and a youtube account has to follow suit or be left in the dust. Especially after Redbeard's Garage posted his video of the ported head install on the Motomax, although he is still running a weaksauce carb.

Would I like to know what I got for all of my time and money? Sure, I guess, but to tell the truth I don't really need it. I know how the bike felt with every change, and I know that compared to my last Hawk, the current one is much more powerful. Top speed is a little better, maybe 5mph faster more consistently with the same gearing. The real difference is the acceleration and tractor factor pulling up hills. Something I got to witness first hand with a stock TT250 slowing down up a fairly steep hill that I had to let off just so I wouldn't hit the guy because I was still pulling, with basically 5 less teeth out back than him, a heavier chain, and about 80lbs more weight.

If anything I often have to temper peoples enthusiasm with the gains in question and the idea that they formed in their head of what it is like vs. reality. Especially with the younger guys. They seem to think big carb and head porting will turn an anemic air cooled 229cc OHV engine into a 90mph capable dual sport. We all know that isn't the case, which is why I tend to underplay it a bit, and try to shift the focus away from top speed and more toward pulling power. Going faster than 70 on one of these bikes isn't for the faint of heart, which is why I have mine geared the way I do.

Baskt_Case · 05-19-2020, 07:44 PM

Well said Dan, keeping traffic off my tail in hilly 55 zones is one of my top goals here.

Megadan · 05-19-2020, 08:03 PM

Quote:

Originally Posted by Baskt_Case

Well said Dan, keeping traffic off my tail in hilly 55 zones is one of my top goals here.

I can pull most hills in 5th at 55mph until we start talking steeper grades like 6%+, or one heck of a head wind on a milder grade. Even then I can usually still hold 55, although I might be pretty pegged lol. Again, gearing plays a factor, and never forget that I am a big heavy guy, so smaller people may struggle less on inclines. I am literally the worst person to put on one of these bikes for a top speed or hill test

China Rider 27 · 05-19-2020, 08:08 PM

I have only been around here for a little over a year and I can see, you and Jerry, Silva, and others have been the innovators on the head porting and other performance improvements. I mean we all copy and follow you guys! Imitation is the best form of flattery! We do all admire your work and appreciate your knowledge, suggestions, and assistance.

Head porting is going to be a big thing in the future and the PE30 carb arrangements too. That is due to you and Jerry Hawk some others. Good job!

I agree about top speed, it does not really mean much and depends on so many variables. People will always be interested in top speed at the expense of other considerations. Speed is thrilling. It is something people just got to know. On my HAWK it is sketchy at WOT and I agree frankly without some good suspension modifications not somewhere I want to spend a lot of time, nor do I recommend other do either. My real interest is as a measure of performance. "Experience" is just as valuable and real as a number and maybe at the heart of satisfaction. If it feels like it is going fast and your satisfied, do you really need anything else.

One day I will be in the Head porting club!

Megadan · 05-19-2020, 09:29 PM

Quote:

Originally Posted by China Rider 27

I have only been around here for a little over a year and I can see, you and Jerry, Silva, and others have been the innovators on the head porting and other performance improvements. I mean we all copy and follow you guys! Imitation is the best form of flattery! We do all admire your work and appreciate your knowledge, suggestions, and assistance.

Head porting is going to be a big thing in the future and the PE30 carb arrangements too. That is due to you and Jerry Hawk some others. Good job!

I agree about top speed, it does not really mean much and depends on so many variables. People will always be interested in top speed at the expense of other considerations. Speed is thrilling. It is something people just got to know. On my HAWK it is sketchy at WOT and I agree frankly without some good suspension modifications not somewhere I want to spend a lot of time, nor do I recommend other do either. My real interest is as a measure of performance. "Experience" is just as valuable and real as a number and maybe at the heart of satisfaction. If it feels like it is going fast and your satisfied, do you really need anything else.

One day I will be in the Head porting club!

Just like when I arrived here and borrowed ideas and upgrades from those before me. It's the evolution and progress at work lol. A vast majority of my Resource guide is information passed on from other guys that I just collected.

I look forward to your thread on it. Just as I can't wait to see the results from this one. This is the first bike where somebody decided they were going to go all out. Most of us just took the cheap bastards route and made the most of what was already there.

China Rider 27 · 05-19-2020, 10:27 PM

There is nothing wrong with the cheap route, that is why we are all here. Thinking about this testing issue some, and I have to say, High speed testing is to dangerous. Especially with these head ported, compression stoked, engines. Baskt case I suggest what you should do is set some assessments based upon speed going up hills and just control for everything but throttle application. Similar to a Dyno, you could apply all out throttle in each case. That way it would be at a slower speed overall speed depending on the hill but give a good comparison.

Baskt_Case · 05-20-2020, 09:01 AM

Quote:

Originally Posted by Megadan

This is the first bike where somebody decided they were going to go all out.

Well, this project sure didn't start out that way, but things kinda got outta hand and now I'm just goin with it!

If the weather cooperates, today is Nibbi day.

OneLeggedRider gave me the fantastic idea to check port volume on the Brozz head before I ship it off. Has anyone checked port volume on a stock Hawk head, or can they? I'm gonna grab a big syringe and some ATF this morning.

And I just found these incredibly helpful calculators this morning. Calculate HP from E/T, Speed, and Weight. Need to find a good app that logs speed vs. time better. My current app only has 1.0 second resolution.

http://www.wallaceracing.com/Calculators.htm

TheChairman · 05-20-2020, 01:39 AM

Just want to say that this thread here is one of the reasons I bought this bike. These super simple engines are always good candidates for building on because it doesn't take a small nestegg, a ton of experience, or specialized tools to get inside there. If you ruin a part, the replacement is cheap and easy to install. 1 or 2HP gains can feel huge.

You mention a cam. Is there a cam available, or is this something that will need to be custom ground? So far the only off the shelf aftermarket performance I've come across is exhaust, intake, and ignition modifications.

05-17-2020, 08:56 AM	#2
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,057	That's not an EGR port. Just so you know. That port is for the air injection. Not one of these bikes has EGR. Glad that my own efforts have inspired you forward, as have those of JerryHawk250 and a couple others. That's the whole point of this forum. Surprised you haven't looked into a camshaft as well. One of the biggest limitations to these CG engines making power is the camshaft. Once you go past 7500 rpm, the power delivery still falls off pretty quickly. Even my own bike will usually top out right at 8000rpm in 5th. Honestly, that "improved" head could probably make great use of the Ressalto cam profile I picked for my bike with just a little cleanup work. In any case, I am subscribing to this thread. I look forward to the progress and your impressions of the results. You should take a moment to install and get the PE30 running on the stock head just for a comparison. It would be nice to have an opinion of the PE30 without port work. __________________ Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124 Last edited by Megadan; 05-17-2020 at 10:23 AM.
	1

05-17-2020, 11:59 AM	#3
Baskt_Case Join Date: Sep 2019 Location: Springfield, KY Posts: 83	Thanks Dan, my blunder for perpetuating the EGR myth. It doesn't help that CSC specifies it as such in their own documentation, tutorials, and parts listings. Add that to the fact that alot of us in less restrictive parts of the country have never had the pleasure of physically dealing with an emissions equipped Chinabike. Indeed, I would not be at my current point of progress in my endeavors without the prior countless hours of research, experimentation, and work performed by you and many others here on the forum. I am very grateful and only hope to expand the knowledge base, and have alot of fun doing it! Ahh yes, the cam. I am eagerly following your thread for your results and impressions. It is definitely a possiblity for the future, perhaps a "Stage III" project. My plate is comfortably full at the moment with just the head and carb upgrade. However, I am definitely watching you closely, especially since you have started talking about a 32mm carb. Have you read the article from CCW that I linked above? Upon my initial inspection of the CGP head, I was quite pleased with the factory port profiles compared to my stock head. Its not a massive difference, but plainly visible. Others have suggested the same as you, that just some touch-up work and matching alone would probably yield a significant improvement over my stock head. However, I am "committed" at this point, my heart is set on professional head work. I just wanna see where this goes. In regards to a future possible cam upgrade, heavier valve springs are definitely on the table with the builder. Originally I was going to wait to install the carb simultaneously with the head but as you and one other individual have pointed out, it would be nice to quantify the gains of the carb and head separately. So carb installation will commence soon! -Aaron __________________ 2018 Hawk - Nibbi PE30, Nibbi Intake, UNI Filter, Ebay Exhaust, NGK 4929 (non-Iridium), 428 D.I.D. X-Ring, 15/40 Sprockets, Walmart AGM Battery, IMS Shifter, Full LED Lighting, Digital Cluster, CSC Swingarm Pin, Modified Chain Adjusters, Upgraded Wheel Bearings MPH Cruise, MPG
	1

05-19-2020, 12:35 AM	#5
Baskt_Case Join Date: Sep 2019 Location: Springfield, KY Posts: 83	So today I was able to nail down specifics with the engine builder regarding exactly what work will be performed. I should have the head shipped out in the next day or two. I will be using A.P.E. Racing in Rosamond, CA. These guys didn't even flinch when I said it was a CG motor. Communication with them has been nothing short of professional. Disassemble, Clean, Inspect. CNC Porting (plus match to my gaskets). Polish on exhaust only. Unshroud valves and address quench gap. Multi-Angle Serdi Valve Job Bronze Guides Stainless Valves Heavy Duty Springs Titanium Retainers Deck 0.8mm (.031"). Assemble and Flow Bench $439 Shipped (both ways) For comparison, they will sell you a brand new ready-to-race CRF250 head for $945 + Shipping. __________________ 2018 Hawk - Nibbi PE30, Nibbi Intake, UNI Filter, Ebay Exhaust, NGK 4929 (non-Iridium), 428 D.I.D. X-Ring, 15/40 Sprockets, Walmart AGM Battery, IMS Shifter, Full LED Lighting, Digital Cluster, CSC Swingarm Pin, Modified Chain Adjusters, Upgraded Wheel Bearings MPH Cruise, MPG
	0

05-19-2020, 10:40 AM	#6
China Rider 27 Join Date: Dec 2018 Location: PNW Posts: 982	I would want to get some objective and quantifiable performance measures of my motor to do a comparison of before and after. Dyno? Last edited by China Rider 27; 05-19-2020 at 12:04 PM.
	0

05-19-2020, 12:38 PM	#7
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,057	You will definitely have the most prepped head of anybody on this site. That is race level stuff through and through and not the typical budget DIY job. __________________ Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124
	1

05-19-2020, 07:24 PM	#8
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,057	A dyno would be the best way by far, but for many the access to one is either limited, or otherwise impossible. Only one in my city, and you have to book it 8-10 weeks in advance, and even then there is no guarantee of getting the day you scheduled because they don't run the dyno if the temps go above 90F outside, or below 50F. What is kind of funny is the influx of bigger carb installs and ported heads as of late. My first year or so on this forum, the biggest and baddest mods people ever talked about was exhausts or decats, VM26 car clones, airbox mods or pod filters. Then one day I post a thread about head porting after buying a head, then a couple other guys, ie Jerry, Silva, and at least one other I can't remember all decided it was a good idea too, and thus in a short span all of us had ported heads. Not one dyno. No quantified results with a dyno or otherwise, just people taking our word for it, and the proof was in the pudding. Then for a while, nobody else really dove in right away. Not sure if they were too afraid or what, but it stayed pretty mute. Then Jerry installed his PWK carb, and not long after I installed me PE30. I made a couple of videos and posts here exclaiming "Holy Moly!" at the increase in power and torque across the entire rpm range. Up to that point I was running the PZ30B, and with the ported head it felt decently stronger than before, but the result felt about the same as installing the exhaust on the bike. A good increase, but nothing too outrageous on its own. Once I gave the head the air to actually breathe, it was a completely different story. Jerry posting similar results with his PWK carb. Within a few months of us posting our results, a few more popped up here and there and they back up our own words, and thus a chain reaction. Now it almost seems like everybody with a chinabike and a youtube account has to follow suit or be left in the dust. Especially after Redbeard's Garage posted his video of the ported head install on the Motomax, although he is still running a weaksauce carb. Would I like to know what I got for all of my time and money? Sure, I guess, but to tell the truth I don't really need it. I know how the bike felt with every change, and I know that compared to my last Hawk, the current one is much more powerful. Top speed is a little better, maybe 5mph faster more consistently with the same gearing. The real difference is the acceleration and tractor factor pulling up hills. Something I got to witness first hand with a stock TT250 slowing down up a fairly steep hill that I had to let off just so I wouldn't hit the guy because I was still pulling, with basically 5 less teeth out back than him, a heavier chain, and about 80lbs more weight. If anything I often have to temper peoples enthusiasm with the gains in question and the idea that they formed in their head of what it is like vs. reality. Especially with the younger guys. They seem to think big carb and head porting will turn an anemic air cooled 229cc OHV engine into a 90mph capable dual sport. We all know that isn't the case, which is why I tend to underplay it a bit, and try to shift the focus away from top speed and more toward pulling power. Going faster than 70 on one of these bikes isn't for the faint of heart, which is why I have mine geared the way I do. __________________ Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124
	1

05-19-2020, 07:44 PM	#9
Baskt_Case Join Date: Sep 2019 Location: Springfield, KY Posts: 83	Well said Dan, keeping traffic off my tail in hilly 55 zones is one of my top goals here. __________________ 2018 Hawk - Nibbi PE30, Nibbi Intake, UNI Filter, Ebay Exhaust, NGK 4929 (non-Iridium), 428 D.I.D. X-Ring, 15/40 Sprockets, Walmart AGM Battery, IMS Shifter, Full LED Lighting, Digital Cluster, CSC Swingarm Pin, Modified Chain Adjusters, Upgraded Wheel Bearings MPH Cruise, MPG
	1

05-19-2020, 08:08 PM	#11
China Rider 27 Join Date: Dec 2018 Location: PNW Posts: 982	I have only been around here for a little over a year and I can see, you and Jerry, Silva, and others have been the innovators on the head porting and other performance improvements. I mean we all copy and follow you guys! Imitation is the best form of flattery! We do all admire your work and appreciate your knowledge, suggestions, and assistance. Head porting is going to be a big thing in the future and the PE30 carb arrangements too. That is due to you and Jerry Hawk some others. Good job! I agree about top speed, it does not really mean much and depends on so many variables. People will always be interested in top speed at the expense of other considerations. Speed is thrilling. It is something people just got to know. On my HAWK it is sketchy at WOT and I agree frankly without some good suspension modifications not somewhere I want to spend a lot of time, nor do I recommend other do either. My real interest is as a measure of performance. "Experience" is just as valuable and real as a number and maybe at the heart of satisfaction. If it feels like it is going fast and your satisfied, do you really need anything else. One day I will be in the Head porting club!
	1

05-19-2020, 10:27 PM	#13
China Rider 27 Join Date: Dec 2018 Location: PNW Posts: 982	There is nothing wrong with the cheap route, that is why we are all here. Thinking about this testing issue some, and I have to say, High speed testing is to dangerous. Especially with these head ported, compression stoked, engines. Baskt case I suggest what you should do is set some assessments based upon speed going up hills and just control for everything but throttle application. Similar to a Dyno, you could apply all out throttle in each case. That way it would be at a slower speed overall speed depending on the hill but give a good comparison.
	2

05-20-2020, 01:39 AM	#15
TheChairman Join Date: May 2020 Location: Philadelphia Posts: 115	Just want to say that this thread here is one of the reasons I bought this bike. These super simple engines are always good candidates for building on because it doesn't take a small nestegg, a ton of experience, or specialized tools to get inside there. If you ruin a part, the replacement is cheap and easy to install. 1 or 2HP gains can feel huge. You mention a cam. Is there a cam available, or is this something that will need to be custom ground? So far the only off the shelf aftermarket performance I've come across is exhaust, intake, and ignition modifications.
	0