Hawk 250 mods and carb jetting

Addy1414 · 07-14-2020, 01:21 AM

I found a hawk with 700 miles for $800 that looked practically new and couldn’t pass it up. Turns out I was pretty impressed with the bike. I have 17/45 sprockets and a print chain coming in the mail tomorrow, along with a performance exhaust and a PE30 nibbi carburetor. My question is what jets should I be using in this carb? And I’m also curious on what other mods I should do? Anything with suspension maybe o feel the rear is a little soft. I want to try and stay away from any air mods I like the air box it keeps all the extra unwanted moisture out when off-roading In wet conditions.

Addy1414 · 07-14-2020, 01:23 AM

I meant to say a O-ring chain not a print chain.

ChrisWNY · 07-14-2020, 09:04 AM

Optimal carb jet size depends on a number of factors. Since you're planning on upgrading the exhaust, you'll need a larger main jet (compared to stock) since the Hawk will run even leaner with improved exhaust airflow. I'd order a number of different-sized jets, start with a 110 or 115 and go from there. Swap the carb, throw in a larger main jet, ride it for awhile and find out how it performs. If it's not to your liking, you can upgrade parts as you go.

Wild Dog · 07-14-2020, 09:08 AM

Quote:

Originally Posted by Addy1414

I found a hawk with 700 miles for $800 that looked practically new and couldn’t pass it up. Turns out I was pretty impressed with the bike. I have 17/45 sprockets and a print chain coming in the mail tomorrow, along with a performance exhaust and a PE30 nibbi carburetor. My question is what jets should I be using in this carb? And I’m also curious on what other mods I should do? Anything with suspension maybe o feel the rear is a little soft. I want to try and stay away from any air mods I like the air box it keeps all the extra unwanted moisture out when off-roading In wet conditions.

This is a good post about jetting the Nibbi PE30 for the Hawk 250.

http://chinariders.net/showthread.php?t=23923

While his hawk has few more mods than yours, it is a nice starting point. It's better to start jetting on the rich side than in the lean side.

Kenstogie · 07-14-2020, 11:47 AM

I too have a "Mikuni" VM26 clone... with an aftermarket exhaust.....
I run a 27.5 Slow jet, the jet needle is on the second richest setting (of 5), and am running a 112.5 Main, Fuel/Air is 1 1/2 turns out, Stock air intake setup. All my jets are actual Mikuni's from Jets r us....

I did buy a Pod air filter but is not on yet and I'd bet the Main could go up a bit more maybe 120 but runs fine for me with the 112.5.... I am at about 300-400 above sea level but often am in the trails at various elevations +- 500 feet i'd guess....

It does require a little "blip" of throttle from a stand still (I may never change it though) but other than that it runs pretty consistent through the entire throttle....

Addy1414 · 07-15-2020, 01:31 AM

Yea I found that thread early this morning and I plan on trying out a 35 and 130 jets since I don’t have a 135 at the moment. I attempted to install the PE30 carburetor and ran into a clearance problem... I believe to make it work I need to get a curved intake manifold and a curved aftermarket air filter which bums me out I can’t use the air box since I do a lot of off road riding and don’t like how it’s exposed to all the dirt and moisture. If anyone has any thoughts on a different route I should take to install it would be appreciated

JsonGB · 07-16-2020, 01:06 PM

It's not necessary, but I invested in a Gunson Colortune years back and it has come in handy many times when trying to figure out jetting combos. Here is a decent youtube clip showing how it works:

I swapped out the PZ30 carb on my 2020 TBR7 (basically a 250 Hawk) for the Mikuni clone and kept the pilot jet that was in it. I started off with a 110 main and it was running rich (orange) so went down to a 105, moved the needle clip down to 2nd to last setting, idle screw out 2 turns, and it is running right where it needs to be (in the blue). Really depends on where you live (elevation...i'm in central Vermont about 600-700 elevation) and every bike setup is different. Being able to see the color of the spark really helps me to fine tune it...the extremes are easy to figure out (racing rpms or boggin out) it's the fine tuning that is tricky for me.

Kenstogie · 07-17-2020, 11:56 AM

I also have the mikuni clone vm26... with the mixture screw does screwing in ritchen the mix or make it.leaner??

Magician16 · 07-17-2020, 03:46 PM

Quote:

Originally Posted by JsonGB

It's not necessary, but I invested in a Gunson Colortune years back and it has come in handy many times when trying to figure out jetting combos. Here is a decent youtube clip showing how it works:

I swapped out the PZ30 carb on my 2020 TBR7 (basically a 250 Hawk) for the Mikuni clone and kept the pilot jet that was in it. I started off with a 110 main and it was running rich (orange) so went down to a 105, moved the needle clip down to 2nd to last setting, idle screw out 2 turns, and it is running right where it needs to be (in the blue). Really depends on where you live (elevation...i'm in central Vermont about 600-700 elevation) and every bike setup is different. Being able to see the color of the spark really helps me to fine tune it...the extremes are easy to figure out (racing rpms or boggin out) it's the fine tuning that is tricky for me.

I never heard of that colortune. Over the years I could have easily paid for it from all the plug chops I've done.

cyclone123 · 12-29-2020, 03:11 PM

I purchased a short straight intake that has to mount to the stock intake but due to the design you cannot mount the hose due to lack of clearance between the mounting bolts and the hose? I purchased the Nibbi intake, what would be the best intake to mount with this carb and a KN type angled filter? Any help would be appreciated. thanks

07-14-2020, 01:21 AM	#1
Addy1414 Join Date: Jul 2020 Posts: 4	Hawk 250 mods and carb jetting I found a hawk with 700 miles for $800 that looked practically new and couldn’t pass it up. Turns out I was pretty impressed with the bike. I have 17/45 sprockets and a print chain coming in the mail tomorrow, along with a performance exhaust and a PE30 nibbi carburetor. My question is what jets should I be using in this carb? And I’m also curious on what other mods I should do? Anything with suspension maybe o feel the rear is a little soft. I want to try and stay away from any air mods I like the air box it keeps all the extra unwanted moisture out when off-roading In wet conditions.
	0

07-14-2020, 09:04 AM	#3
ChrisWNY Join Date: Jul 2018 Posts: 212	Optimal carb jet size depends on a number of factors. Since you're planning on upgrading the exhaust, you'll need a larger main jet (compared to stock) since the Hawk will run even leaner with improved exhaust airflow. I'd order a number of different-sized jets, start with a 110 or 115 and go from there. Swap the carb, throw in a larger main jet, ride it for awhile and find out how it performs. If it's not to your liking, you can upgrade parts as you go. __________________ 2018 RPS Hawk 250cc Mods so far: 1. Mikuni VM26 Carburetor w/#115 main jet 2. 17T/45T JT sprockets 3. JT 428 X-ring chain 4. Air box mod 5. Hawk Digital Cluster 6. Aftermarket IMS shift lever 7. Performance Aftermarket Exhaust 8. 295mm Nitrogen Gas Monoshock, 20W oil front forks
	1

07-14-2020, 11:47 AM	#5
Kenstogie Join Date: Apr 2019 Posts: 336	I too have a "Mikuni" VM26 clone... with an aftermarket exhaust..... I run a 27.5 Slow jet, the jet needle is on the second richest setting (of 5), and am running a 112.5 Main, Fuel/Air is 1 1/2 turns out, Stock air intake setup. All my jets are actual Mikuni's from Jets r us.... I did buy a Pod air filter but is not on yet and I'd bet the Main could go up a bit more maybe 120 but runs fine for me with the 112.5.... I am at about 300-400 above sea level but often am in the trails at various elevations +- 500 feet i'd guess.... It does require a little "blip" of throttle from a stand still (I may never change it though) but other than that it runs pretty consistent through the entire throttle.... __________________ been around bikes for a while.... honda 72 cb200t, zuki 96?/2002 katana, 12 vstrom,09 vstar, kawi ltd440, 82 zuki Gs1100, Tao Tbr7 all about the Tao MotorsTBR7 http://www.chinariders.net/showthread.php?t=25553
	0

07-17-2020, 11:56 AM	#8
Kenstogie Join Date: Apr 2019 Posts: 336	I also have the mikuni clone vm26... with the mixture screw does screwing in ritchen the mix or make it.leaner?? __________________ been around bikes for a while.... honda 72 cb200t, zuki 96?/2002 katana, 12 vstrom,09 vstar, kawi ltd440, 82 zuki Gs1100, Tao Tbr7 all about the Tao MotorsTBR7 http://www.chinariders.net/showthread.php?t=25553
	0

12-29-2020, 03:11 PM	#10
cyclone123 Join Date: Nov 2020 Posts: 4	what intake to mount the Nibbi 30 carb to a RPS 250 Hawk I purchased a short straight intake that has to mount to the stock intake but due to the design you cannot mount the hose due to lack of clearance between the mounting bolts and the hose? I purchased the Nibbi intake, what would be the best intake to mount with this carb and a KN type angled filter? Any help would be appreciated. thanks
	0

07-14-2020, 01:23 AM	#2
Addy1414 Join Date: Jul 2020 Posts: 4	I meant to say a O-ring chain not a print chain.
	0

07-15-2020, 01:31 AM	#6
Addy1414 Join Date: Jul 2020 Posts: 4	Yea I found that thread early this morning and I plan on trying out a 35 and 130 jets since I don’t have a 135 at the moment. I attempted to install the PE30 carburetor and ran into a clearance problem... I believe to make it work I need to get a curved intake manifold and a curved aftermarket air filter which bums me out I can’t use the air box since I do a lot of off road riding and don’t like how it’s exposed to all the dirt and moisture. If anyone has any thoughts on a different route I should take to install it would be appreciated
	0

07-16-2020, 01:06 PM	#7
JsonGB Join Date: Jul 2020 Location: Vermont Posts: 3	It's not necessary, but I invested in a Gunson Colortune years back and it has come in handy many times when trying to figure out jetting combos. Here is a decent youtube clip showing how it works: I swapped out the PZ30 carb on my 2020 TBR7 (basically a 250 Hawk) for the Mikuni clone and kept the pilot jet that was in it. I started off with a 110 main and it was running rich (orange) so went down to a 105, moved the needle clip down to 2nd to last setting, idle screw out 2 turns, and it is running right where it needs to be (in the blue). Really depends on where you live (elevation...i'm in central Vermont about 600-700 elevation) and every bike setup is different. Being able to see the color of the spark really helps me to fine tune it...the extremes are easy to figure out (racing rpms or boggin out) it's the fine tuning that is tricky for me.
	1