Hawk 250 idle and vibration issue

McMiller16 · 06-23-2018, 11:12 AM

i have had my hawk 250 for about a year now and it has been running nicely with a few minor problems, that i have fixed... mostly. i had problems with the original carburetor and having gas blow back into the air filter and also idle problems so i upgraded the carb to the one suggested. it has fixed the fuel blowing into the filter problem but i am still having issues with the idle. while the engine is cool it idles fairly well, but after i drive it for a while the idle speeds up and runs too fast. ive played with the idle screw on the carb but it seems to only help change the idle speed when it is cool, and always speeds back up when it warms up.
any ideas?
also i am having a problem with the bike vibrating too much. ive tightened all the bolts and screws and lock-tighted them all, after loosing most of them. i it has gotten so bad that it actually sheared one of the bolts holding the exhaust to the engine block.
any ideas or fixes would be greatly appreciated. thanks.

Megadan · 06-23-2018, 11:18 AM

When was the last time you adjusted the valves?

pete · 06-23-2018, 10:50 PM

Air screw.... get it idleing hot motor..turn the air screw in/out till you get the
fastest idle... then back it in 1/8 -1/4 of a turn... then adjust the idle
with the throttle stop screw on the carb...
cold idle/running will be taken care of by the choke till the motor is warm/hot..
you can't set the idle on a cold motor....

vibration...check the engine mount bolts are at the right touque setting...

..

Vidlakj · 06-23-2021, 06:12 PM

Hey everyone! Does anyone know the factory starting point for the idle screw? Mine was idling but really slow. I turned the screw and it died. Now it won’t idle, so I’m trying to get back to baseline. How many turns from bottom out?

Megadan · 06-23-2021, 06:41 PM

Quote:

Originally Posted by Vidlakj

Hey everyone! Does anyone know the factory starting point for the idle screw? Mine was idling but really slow. I turned the screw and it died. Now it won’t idle, so I’m trying to get back to baseline. How many turns from bottom out?

There is no real factory setting. For idle mixture adjustment the generic starting point is 1.5 turns out from seated. From there minor adjustments may be needed.

**JerryHawk250** · 06-24-2021, 08:12 AM

Quote:

Originally Posted by Vidlakj

Hey everyone! Does anyone know the factory starting point for the idle screw? Mine was idling but really slow. I turned the screw and it died. Now it won’t idle, so I’m trying to get back to baseline. How many turns from bottom out?

Are you trying to adjust idle speed or idle mixture screw? to increase idle speed turn the screw clock wise.

Vidlakj · 06-25-2021, 12:00 PM

Thank you guys for the quick response!! It's frustrating! It's the idle speed screw (throttle stop screw?) on the side. I just got this bike from my son (lives in different town). He's had it for a year and hadn't touched it. So I acquired it last weekend and the first things I did was: changed the oil, adjusted the valves (.002), new battery, and checked the spark plug. First crank took a couple of turns and some choke, but it fired up. I blipped the throttle a little to keep it idling, but it did stay running. It smoked like crazy all over the bike, though, I assume from shipping oils and the like on the exhaust and cylinder head. Felt great that it started and idled. Well, it seemed that the idle was just barely fast enough to keep running (very slow lope). So, I touched the screw! Now, it is very hard to even get started and if I let go of the throttle, it dies immediately. I'll try the 1.5 turns out from seated and start from there. It's frustrating because I read that your not supposed to adjust the screw until the bike is warmed up, but I can't let the throttle go and let it idle without it dying. By the way, MEGADAN, I'm in Scottsbluff, Nebraska! I saw you were in Omaha! My son wanted this to be a commuter bike for Lincoln!

stewbrash · 06-25-2021, 12:19 PM

Hello, to me it appears you have confused the 'Idle Screw' with the 'Air Mixture Screw.' The idle screw is the one on the side and it is totally variable in/out to adjust the RPM only. The '1.5 turns' previously described is only for the 'Air Mixture Screw' and is only accessible (if this is stock, you will have to remove the carburetor and remove the plug covering it) from underneath with a small screwdriver. Since you are having problems with it idling...hold the engine at an idle just high enough to keep it running...then turn the 'Idle Screw' (on the side) clockwise until you hear the rpms rise...then release the throttle and re-adjust the 'Idle Screw' in/out to arrive at the idle you're comfortable with.

J4Fun · 06-25-2021, 12:24 PM

You said your son had it for a year right? Was there any fuel in it? Mine came with some rotten fuel in it that I removed before starting, just a thought.

Vidlakj · 06-25-2021, 01:10 PM

Stewbrash: Yes, sorry, I am referring to the screw with the spring on the side of the carb. I haven't removed the plug covering the screw on the bottom of the carb. Thank you! Great advice-makes sense!

J4Fun: There was just a tiny bit of gas in it, but I got siphoned what I could out and put in fresh 91 in it. It started and idled. I could shut it off, start it and let it sit there and idle. Pretty exciting that I got it going. BUT, then I touched the idle (throttle stop) screw on the side of the carb and now it's very difficult to get it to start and will die immediately as soon as I let the throttle down.

stewbrash · 06-25-2021, 01:30 PM

Possibly a clogged pilot jet.

Bruces · 06-25-2021, 03:57 PM

Pull the bowl off the bottom of the carb and see the white junk in the bottom .It needs a good cleaning ,and it probably needs to be rejected anyways as I don’t see that mentioned in your list .

06-23-2018, 11:12 AM	#1
McMiller16 Join Date: Jul 2017 Posts: 3	Hawk 250 idle and vibration issue i have had my hawk 250 for about a year now and it has been running nicely with a few minor problems, that i have fixed... mostly. i had problems with the original carburetor and having gas blow back into the air filter and also idle problems so i upgraded the carb to the one suggested. it has fixed the fuel blowing into the filter problem but i am still having issues with the idle. while the engine is cool it idles fairly well, but after i drive it for a while the idle speeds up and runs too fast. ive played with the idle screw on the carb but it seems to only help change the idle speed when it is cool, and always speeds back up when it warms up. any ideas? also i am having a problem with the bike vibrating too much. ive tightened all the bolts and screws and lock-tighted them all, after loosing most of them. i it has gotten so bad that it actually sheared one of the bolts holding the exhaust to the engine block. any ideas or fixes would be greatly appreciated. thanks.
	0

06-23-2018, 11:18 AM	#2
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,032	When was the last time you adjusted the valves? __________________ 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

06-23-2018, 10:50 PM	#3
pete Join Date: Jan 2012 Location: ChCh , NZ Posts: 2,262	Air screw.... get it idleing hot motor..turn the air screw in/out till you get the fastest idle... then back it in 1/8 -1/4 of a turn... then adjust the idle with the throttle stop screw on the carb... cold idle/running will be taken care of by the choke till the motor is warm/hot.. you can't set the idle on a cold motor.... vibration...check the engine mount bolts are at the right touque setting... .. __________________ 09 XT660R ... 06 TTR250 ... 80 Montesa H6 125 Enduro... 77 Montesa Cota 348 MRR "Malcom Rathnell Replica"... Current resto projects.. 81 Honda CT110... 80 Kawasaki KL250A1... 11 Husaburg TE125 enduro... "sold" along with another 31... Lifan 125 Pitbike.. "stolen" ... KIWI BIKER FORUM...... http://www.kiwibiker.co.nz/forums/content.php All the best offroad rides in NZ... http://www.remotemoto.com/ E-mail... xtpete1@gmail.com
	0

06-25-2021, 12:00 PM	#7
Vidlakj Join Date: Jun 2021 Posts: 3	Thank you guys for the quick response!! It's frustrating! It's the idle speed screw (throttle stop screw?) on the side. I just got this bike from my son (lives in different town). He's had it for a year and hadn't touched it. So I acquired it last weekend and the first things I did was: changed the oil, adjusted the valves (.002), new battery, and checked the spark plug. First crank took a couple of turns and some choke, but it fired up. I blipped the throttle a little to keep it idling, but it did stay running. It smoked like crazy all over the bike, though, I assume from shipping oils and the like on the exhaust and cylinder head. Felt great that it started and idled. Well, it seemed that the idle was just barely fast enough to keep running (very slow lope). So, I touched the screw! Now, it is very hard to even get started and if I let go of the throttle, it dies immediately. I'll try the 1.5 turns out from seated and start from there. It's frustrating because I read that your not supposed to adjust the screw until the bike is warmed up, but I can't let the throttle go and let it idle without it dying. By the way, MEGADAN, I'm in Scottsbluff, Nebraska! I saw you were in Omaha! My son wanted this to be a commuter bike for Lincoln! Last edited by Vidlakj; 06-25-2021 at 12:15 PM. Reason: added info
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06-23-2021, 06:12 PM	#4
Vidlakj Join Date: Jun 2021 Posts: 3	Hey everyone! Does anyone know the factory starting point for the idle screw? Mine was idling but really slow. I turned the screw and it died. Now it won’t idle, so I’m trying to get back to baseline. How many turns from bottom out?
	0

06-25-2021, 12:19 PM	#8
stewbrash Join Date: Oct 2016 Posts: 405	Hello, to me it appears you have confused the 'Idle Screw' with the 'Air Mixture Screw.' The idle screw is the one on the side and it is totally variable in/out to adjust the RPM only. The '1.5 turns' previously described is only for the 'Air Mixture Screw' and is only accessible (if this is stock, you will have to remove the carburetor and remove the plug covering it) from underneath with a small screwdriver. Since you are having problems with it idling...hold the engine at an idle just high enough to keep it running...then turn the 'Idle Screw' (on the side) clockwise until you hear the rpms rise...then release the throttle and re-adjust the 'Idle Screw' in/out to arrive at the idle you're comfortable with.
	0

06-25-2021, 12:24 PM	#9
J4Fun Join Date: May 2021 Posts: 297	You said your son had it for a year right? Was there any fuel in it? Mine came with some rotten fuel in it that I removed before starting, just a thought.
	0

06-25-2021, 01:10 PM	#10
Vidlakj Join Date: Jun 2021 Posts: 3	Stewbrash: Yes, sorry, I am referring to the screw with the spring on the side of the carb. I haven't removed the plug covering the screw on the bottom of the carb. Thank you! Great advice-makes sense! J4Fun: There was just a tiny bit of gas in it, but I got siphoned what I could out and put in fresh 91 in it. It started and idled. I could shut it off, start it and let it sit there and idle. Pretty exciting that I got it going. BUT, then I touched the idle (throttle stop) screw on the side of the carb and now it's very difficult to get it to start and will die immediately as soon as I let the throttle down.
	0

06-25-2021, 01:30 PM	#11
stewbrash Join Date: Oct 2016 Posts: 405	Possibly a clogged pilot jet.
	0

06-25-2021, 03:57 PM	#12
Bruces Join Date: May 2018 Posts: 1,584	Pull the bowl off the bottom of the carb and see the white junk in the bottom .It needs a good cleaning ,and it probably needs to be rejected anyways as I don’t see that mentioned in your list .
	0