Hawk Carburetor Problem

fishtime9 · 03-26-2016, 07:01 PM

I just installed the mikuni carburetor with a 115 main jet and 30 slow jet. I am amazed of the power and torque the bike has now, as well as it cruises at around 60 m/ph. However, it sputers constantly and it loses power when holding it at one constant speed setting. Could this be because of my pilot screw position? I can also upload a video if needed for further examination about this problem.

TXDSRIDER · 03-26-2016, 07:39 PM

Does it do it no matter where in the Rev range you hold it.

Wolftrax · 03-26-2016, 08:15 PM

Air leak, loose battery connection.

newrider93 · 03-26-2016, 08:29 PM

Sounds like an air leak. Check the air vent from the box to carb. The silicon they used on mine was not heat resistant and gave away. I bought some automotive sealer at the local auto store and sealed it up.

fishtime9 · 03-26-2016, 10:20 PM

I checked my air box. However, it does not seem to have a air leak. Is there anything else that could be causing this, and it only occurs when holding the speed at a steady position. Basically, it sputters at that specific type of point and seems like its loosing power. I can upload a video tomorrow evening of it, if that helps?

newrider93 · 03-26-2016, 10:46 PM

What's the spark plug look like? Did you replace it with an Ngk?

Ron B · 03-27-2016, 08:41 AM

when I got my carb I ran my mixture screw in and counted, it came a little over 4 turns out. I set it a tad over 1 and a half out

2LZ · 03-27-2016, 10:38 AM

Spark plug as mentioned? Get an NGK D8EA or the iridium equivalent, DR8EIX.
What position is your slide clip in? Go one up from the bottom slot (4th down).
Mixture screw should be about 1 and 3/4 turns out.
Have you adjusted the valves?

I'm wondering about all these Hawks and Storms that are doing all the intake mods and not doing anything with the exhaust, regarding removing the cat or changing the muffler.

chuck · 03-27-2016, 06:45 PM

I did the carb upgrade and installed a Pro circuit T4 full exhaust and the bike feel like it gained a few horses.

fishtime9 · 03-27-2016, 09:42 PM

I will most likely take the carburetor next weekend off again and mess with the pilot screw. However, I personally think that the jet setup in general is not made for this engine.

mq1991 · 03-28-2016, 12:37 AM

Quote:

Originally Posted by fishtime9

I will most likely take the carburetor next weekend off again and mess with the pilot screw. However, I personally think that the jet setup in general is not made for this engine.

I did the upgrade, it took me a few tries to get the jetting right, but now it works awesome. Mine sputtered bad at high rpm when I was running it too rich. I went from 120 to 125, and it got worse, then I went to 115 and it cleared up.

Play around with your jetting, it takes awhile and can be frustrating but its worth it.

fishtime9 · 03-28-2016, 05:44 PM

Quote:

Originally Posted by mq1991

I did the upgrade, it took me a few tries to get the jetting right, but now it works awesome. Mine sputtered bad at high rpm when I was running it too rich. I went from 120 to 125, and it got worse, then I went to 115 and it cleared up.

Play around with your jetting, it takes awhile and can be frustrating but its worth it.

I am currently running a 115 main jet, as well as 30 slow jet.

Sport Rider · 03-28-2016, 07:21 PM

Is your pilot screw at 1.5 turns out? Also, what do you have your needle at? Mine is in the second slot from the top. I had a guy with some carb experience ride it this weekend. He said it smelled a little rich but said it rode pretty well. He said no more changes and just to enjoy it.

BlackBike · 03-28-2016, 07:52 PM

I think the smell comes from the cheap ass seal from that gas cap. I made mine tighter by stretching the inner Springs in the cap which helped but she is still a bit gassy.

zingshoen · 03-28-2016, 10:12 PM

could be rich on the idle jet, i found 25 / 115 better, but it shouldn t cause sputter.

i had severe sputter one time from blocked venturis on the air intake side, try running with the airfilter hose disconnected, just for testing.

03-26-2016, 07:01 PM	#1
fishtime9 Join Date: Aug 2015 Posts: 73	Hawk Carburetor Problem I just installed the mikuni carburetor with a 115 main jet and 30 slow jet. I am amazed of the power and torque the bike has now, as well as it cruises at around 60 m/ph. However, it sputers constantly and it loses power when holding it at one constant speed setting. Could this be because of my pilot screw position? I can also upload a video if needed for further examination about this problem.
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03-26-2016, 07:39 PM	#2
TXDSRIDER Join Date: Oct 2015 Location: Houston Tx Posts: 157	Does it do it no matter where in the Rev range you hold it. __________________ Brandon 2014 Hawk 250 Firehawk minibike Previous bikes~ 1995 Yamaha YZ125 1998 Yamaha YZ250 1981 Yamaha YZ465 1987 Honda TRX 250R X2 one stock one modified 2002 Buell Blast 2001 Buell X1 Lightning 2000 Kawasaki ZR7
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03-26-2016, 08:15 PM	#3
Wolftrax Join Date: Sep 2014 Location: Blue Ridge Mtns Ga Posts: 437	Air leak, loose battery connection. __________________ Mark 2015 Haosen Hawk 250 2014 CRF250L 2014 CB500X Rally Raid
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03-27-2016, 10:38 AM	#8
2LZ Join Date: Mar 2010 Location: Volcano, Ca Posts: 7,092	Spark plug as mentioned? Get an NGK D8EA or the iridium equivalent, DR8EIX. What position is your slide clip in? Go one up from the bottom slot (4th down). Mixture screw should be about 1 and 3/4 turns out. Have you adjusted the valves? I'm wondering about all these Hawks and Storms that are doing all the intake mods and not doing anything with the exhaust, regarding removing the cat or changing the muffler. __________________ "Light a fire for a man, and you heat him for a day. Light a man on fire, and you heat him for the rest of his life." 2007 Suzuki DRZ400S (SM convert) 2009 Q Link XP 200 1967 BSA B25 250cc Starfire 2022 Royal Enfield Interceptor 650 2023 Royal Enfield Scram 411 1948 Royal Enfield Model G 350
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03-28-2016, 07:52 PM	#14
BlackBike Join Date: Feb 2016 Location: George West, Texas Posts: 4,097	I think the smell comes from the cheap ass seal from that gas cap. I made mine tighter by stretching the inner Springs in the cap which helped but she is still a bit gassy. __________________ ***************************************** 2015 Bashan"Blaze" BS250GY-31 (DB-07K-250) GONE 2017 Suzuki V Strom 650 XT "We are all born ignorant, but one must work hard to remain stupid." ~Benjamin Franklin~
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03-26-2016, 08:29 PM	#4
newrider93 Join Date: Jun 2015 Location: Missouri USA Posts: 164	Sounds like an air leak. Check the air vent from the box to carb. The silicon they used on mine was not heat resistant and gave away. I bought some automotive sealer at the local auto store and sealed it up.
	0

03-26-2016, 10:20 PM	#5
fishtime9 Join Date: Aug 2015 Posts: 73	I checked my air box. However, it does not seem to have a air leak. Is there anything else that could be causing this, and it only occurs when holding the speed at a steady position. Basically, it sputters at that specific type of point and seems like its loosing power. I can upload a video tomorrow evening of it, if that helps?
	0

03-26-2016, 10:46 PM	#6
newrider93 Join Date: Jun 2015 Location: Missouri USA Posts: 164	What's the spark plug look like? Did you replace it with an Ngk?
	0

03-27-2016, 08:41 AM	#7
Ron B Join Date: Mar 2016 Location: Tuscaloosa Al. Posts: 433	when I got my carb I ran my mixture screw in and counted, it came a little over 4 turns out. I set it a tad over 1 and a half out
	0

03-27-2016, 06:45 PM	#9
chuck Join Date: Sep 2015 Posts: 436	I did the carb upgrade and installed a Pro circuit T4 full exhaust and the bike feel like it gained a few horses.
	0

03-27-2016, 09:42 PM	#10
fishtime9 Join Date: Aug 2015 Posts: 73	I will most likely take the carburetor next weekend off again and mess with the pilot screw. However, I personally think that the jet setup in general is not made for this engine.
	0

03-28-2016, 07:21 PM	#13
Sport Rider Join Date: Jan 2016 Location: Mooresville NC Posts: 2,044	Is your pilot screw at 1.5 turns out? Also, what do you have your needle at? Mine is in the second slot from the top. I had a guy with some carb experience ride it this weekend. He said it smelled a little rich but said it rode pretty well. He said no more changes and just to enjoy it.
	0

03-28-2016, 10:12 PM	#15
zingshoen Join Date: Jun 2009 Location: Brisbane, Queensland, Australia Posts: 648	could be rich on the idle jet, i found 25 / 115 better, but it shouldn t cause sputter. i had severe sputter one time from blocked venturis on the air intake side, try running with the airfilter hose disconnected, just for testing. __________________ 1971 Garelli Gulp 50cc with open ports and 16 mm Bing Carbie + 1980 Honda XL 223 ZS + 2007 Zongshen LZX200G + DR400SM
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