Another Mikuni Carb jetting question

Slurmss · 05-16-2021, 12:59 AM

Hi all!
I have had a hawk 250 for about a year and have not really touched it in a while due to being at school. I bought a mikuni carb for it after I got it because it wasnt running great at all, but never got the chance to install it or rejet it. I have seen a million posts on this and have found it is generally recommended that you do a pilot jet of 25,27.5, or 30 depending on elevation and a main jet of 105-115 depending on elevation. I was wondering before I just make a guess based on that information what someone with experience with rejetting carbs thinks I should do. I live at about 500 feet above sea level and my bike is fully stock. I was thinking based on everything I have read I was thinking 27.5 and 110 maybe? Does that sound about right? I am going to mess with it but as I have no experience with carbs I want to start as best I can so I do not have to change as much.
Thanks for any help!

Megadan · 05-16-2021, 01:15 AM

Fully stock at 1100ft I found a 25 pilot, 105 main, and needle in the 4th notch down and the idle mixture about 1 3/4 turns out to work very well for me in the hotter months.

A 110 may work better for you, or maybe even a 107.5 if you really want to get into fine tuning. Only way to know for sure is with a proper plug chop.

Chowdy · 08-11-2021, 03:29 PM

So,
I ordered a Vitacci Raven 250. Due in about a week. I wanted to do some of the simple mods right out of the box during assembly. One of which is to upgrade the carb. My intention was to do a drop in replacement of the stock carb with one that is higher quality and more tunable but to make my best starting guess here. What I think I hear is this, will you guys please confirm so I order the right parts? I'll spend my riding life at 200 ft, down to sea level but up to 3700 ft in the National Forests. I think this is an elaboration of this thread, so I'm posting here...

PWK Carburetor 28MM
115
30
1.5 turns out.

(Note: I'm not gutting the airbox. I plan to ride through dirt, mud and creeks with the thing. I need the carb to connect to the stock airbox.)

China Rider 27 · 08-11-2021, 03:48 PM

If your post is correct, that being a PWK 28 is what you are installing---- that is a whole different animal and probably should be set in its own post otherwise it will confuse Mikuni carburetor tuners.

JerseyTBR7 · 08-11-2021, 04:04 PM

I also have a minkuni. At sea level, I am using a 110 main, 27.5 pilot and 1.5 turns out on the fuel/air screw on the bottom middle. I left the needle alone.

Chowdy · 08-17-2021, 09:21 AM

Hey, Thanks Jersey, I'll start where you are. China Rider, you are probably right. I'll refrain from further posts here.

kyle · 08-17-2021, 03:48 PM

Hey.. same carb as the TBR7.. we've started compiling a chart on the website, scroll to the bottom: https://tbr7.com/upgrades/fuel-system/

05-16-2021, 12:59 AM	#1
Slurmss Join Date: May 2021 Posts: 1	Another Mikuni Carb jetting question Hi all! I have had a hawk 250 for about a year and have not really touched it in a while due to being at school. I bought a mikuni carb for it after I got it because it wasnt running great at all, but never got the chance to install it or rejet it. I have seen a million posts on this and have found it is generally recommended that you do a pilot jet of 25,27.5, or 30 depending on elevation and a main jet of 105-115 depending on elevation. I was wondering before I just make a guess based on that information what someone with experience with rejetting carbs thinks I should do. I live at about 500 feet above sea level and my bike is fully stock. I was thinking based on everything I have read I was thinking 27.5 and 110 maybe? Does that sound about right? I am going to mess with it but as I have no experience with carbs I want to start as best I can so I do not have to change as much. Thanks for any help!
	0

05-16-2021, 01:15 AM	#2
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,020	Fully stock at 1100ft I found a 25 pilot, 105 main, and needle in the 4th notch down and the idle mixture about 1 3/4 turns out to work very well for me in the hotter months. A 110 may work better for you, or maybe even a 107.5 if you really want to get into fine tuning. Only way to know for sure is with a proper plug chop. __________________ 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
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08-11-2021, 03:29 PM	#3
Chowdy Join Date: Aug 2021 Location: Richmond, VA Posts: 2	Looking for guidance here too So, I ordered a Vitacci Raven 250. Due in about a week. I wanted to do some of the simple mods right out of the box during assembly. One of which is to upgrade the carb. My intention was to do a drop in replacement of the stock carb with one that is higher quality and more tunable but to make my best starting guess here. What I think I hear is this, will you guys please confirm so I order the right parts? I'll spend my riding life at 200 ft, down to sea level but up to 3700 ft in the National Forests. I think this is an elaboration of this thread, so I'm posting here... PWK Carburetor 28MM 115 30 1.5 turns out. (Note: I'm not gutting the airbox. I plan to ride through dirt, mud and creeks with the thing. I need the carb to connect to the stock airbox.)
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08-17-2021, 09:21 AM	#6
Chowdy Join Date: Aug 2021 Location: Richmond, VA Posts: 2	Looking for guidance here 2 Hey, Thanks Jersey, I'll start where you are. China Rider, you are probably right. I'll refrain from further posts here.
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08-11-2021, 03:48 PM	#4
China Rider 27 Join Date: Dec 2018 Location: PNW Posts: 982	If your post is correct, that being a PWK 28 is what you are installing---- that is a whole different animal and probably should be set in its own post otherwise it will confuse Mikuni carburetor tuners.
	0

08-11-2021, 04:04 PM	#5
JerseyTBR7 Join Date: Oct 2020 Posts: 130	I also have a minkuni. At sea level, I am using a 110 main, 27.5 pilot and 1.5 turns out on the fuel/air screw on the bottom middle. I left the needle alone.
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08-17-2021, 03:48 PM	#7
kyle Join Date: Jun 2021 Posts: 105	Hey.. same carb as the TBR7.. we've started compiling a chart on the website, scroll to the bottom: https://tbr7.com/upgrades/fuel-system/
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