Bike has super aggressive shakes during idle

GoldenBoy1704 · 03-29-2021, 01:50 PM

Hi everyone, I just got my new Hawk 250 to start today and whenever I start it and let it idle it shakes and vibrates. A lot. I'm new to motorcycles and dirt bikes in general so I'm not sure if this is normal or not. If it is an issue and I'm not just being nervous how should I go about fixing this? If you can, please explain it as simply as possible, my knowledge on the subject isn't very great

Thanks,
GoldenBoy

Oldenslow · 03-29-2021, 02:17 PM

I'm not saying there's nothing wrong with your motor -- I'd have to be there to see it for myself -- but it well may be there's nothing wrong with it. A single-cylinder engine is by its nature unbalanced, and although various mechanical features and contrivances serve to reduce vibration in some motors, usually they are going to shake at idle and buzz at speed. On the other hand, something like a 6-cylinder Honda Gold Wing can idle so smoothly you almost have to touch it to make sure it's running. There's a reason single-cylinder engines are often called "thumpers".

GoldenBoy1704 · 03-29-2021, 05:12 PM

Its got a little bit of time before the field I'm practicing on is open so I'm just gonna assume its just my nerves getting to me
Hopefully I don't crash

Update: didn't crash after first ride, and I figured out why the engine kept going nuts. My bike acts as if I'm tugging on the throttle even when I'm not, I think I tightened something on the carb to much. Gonna adjust it and try again

tknj99 · 03-29-2021, 06:53 PM

I'm sure its just normal idle or perhaps a slight adjustment needed.. or hmm.. maybe you got "Harley mode" enabled

TxTaoRider · 03-29-2021, 07:18 PM

Quote:

Originally Posted by tknj99

I'm sure its just normal idle or perhaps a slight adjustment needed.. or hmm.. maybe you got "Harley mode" enabled

If it was in Harley mode, it would've leaked a puddle of oil then quit.

GoldenBoy1704 · 04-05-2021, 11:02 AM

I got it started again after some adjustments and nothing changed, ended up crashing this time. The bike is acting like the throttle is being pulled but its not, its going near full speed whenever its in first gear, is there any way to change that? I don't know about anyone else but I'd rather not go flying off into the distance from 0-12 in 1.3 seconds

Thanks again

franque · 04-05-2021, 12:27 PM

Is the choke on?

GoldenBoy1704 · 04-05-2021, 12:31 PM

Quote:

Originally Posted by franque

Is the choke on?

Yes, full choke. I've tried it at all three choke settings and it does the same thing regardless, I think something at the throttle itself isn't right. I could definitely be wrong though

ikeus685 · 04-05-2021, 12:52 PM

Possible problem is that all slack has ben taken out of the throttle cable. Ensure that there is a little wiggle room.

**JerryHawk250** · 04-05-2021, 01:15 PM

Sounds like you have the idle set way too high. If the idle speed screw does nothing than more than like likely there is not enough slack in the throttle cable or carb slide is in backwards.

Bruces · 04-05-2021, 03:12 PM

The throttle slide might be in backwards

GoldenBoy1704 · 04-05-2021, 07:41 PM

Okay guys, I finally figured it out

I had bought a third party carb to replace the sock one which I heard was junk. On the third party carb there was a little needle that was stopping the slide from going all the way down. It took me a pretty long time to notice this despite it being a really important detail. It still doesn't run perfectly but at least its better, thanks again everyone for all the help!

idle_purr · 04-05-2021, 08:51 PM

Not sure if this will help you or not but my father's hawk with 10 miles on it, had this issue and I discovered that there was not enough slack on my throttle cable and whenever I turned left it overstressed the cable. The throttle cable was actually coming out of the carb at about a 15 degree angle.

I was able to add more slack by shifting the cable to the front side of the cluster, closer to the key. The cable now comes straight out of the carb and the throttle is smooth as butter.

The idle is sporadic, smooth one minute and shaky the next. My father ordered a new carb but it won't be here for about 2 weeks. I assume that will be the resolve we are looking for.

Goldenboy are you able to upload a video to youtube of your engine idling after warm up?

GoldenBoy1704 · 04-05-2021, 09:11 PM

Goldenboy are you able to upload a video to youtube of your engine idling after warm up?[/QUOTE]

I'll get one tomorrow at around 3:30 pm MST when the field I practice in is free again

I have no idea what happened with the quote thing but its not important right now

mtiberio · 04-06-2021, 06:20 PM

one of your motor mount bolts fell out.

03-29-2021, 01:50 PM	#1
GoldenBoy1704 Join Date: Mar 2021 Posts: 25	Bike has super aggressive shakes during idle Hi everyone, I just got my new Hawk 250 to start today and whenever I start it and let it idle it shakes and vibrates. A lot. I'm new to motorcycles and dirt bikes in general so I'm not sure if this is normal or not. If it is an issue and I'm not just being nervous how should I go about fixing this? If you can, please explain it as simply as possible, my knowledge on the subject isn't very great Thanks, GoldenBoy
	0

03-29-2021, 05:12 PM	#3
GoldenBoy1704 Join Date: Mar 2021 Posts: 25	Its got a little bit of time before the field I'm practicing on is open so I'm just gonna assume its just my nerves getting to me Hopefully I don't crash Update: didn't crash after first ride, and I figured out why the engine kept going nuts. My bike acts as if I'm tugging on the throttle even when I'm not, I think I tightened something on the carb to much. Gonna adjust it and try again Last edited by GoldenBoy1704; 03-29-2021 at 05:55 PM.
	0

03-29-2021, 06:53 PM	#4
tknj99 Join Date: Oct 2020 Location: Central VA Posts: 1,254	I'm sure its just normal idle or perhaps a slight adjustment needed.. or hmm.. maybe you got "Harley mode" enabled __________________ 2024 Zuma Storm 150 DLX 2019 Beta 430 RRS 2017 Honda Fury Former China Bikes: Tao DBX1, Brozz 250, CSC RX4, Titan DLX, Templar X
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04-05-2021, 11:02 AM	#6
GoldenBoy1704 Join Date: Mar 2021 Posts: 25	I got it started again after some adjustments and nothing changed, ended up crashing this time. The bike is acting like the throttle is being pulled but its not, its going near full speed whenever its in first gear, is there any way to change that? I don't know about anyone else but I'd rather not go flying off into the distance from 0-12 in 1.3 seconds Thanks again Last edited by GoldenBoy1704; 04-05-2021 at 11:03 AM. Reason: Fixing spelling error
	0

04-05-2021, 01:15 PM	#10
JerryHawk250 Moderator Join Date: Oct 2016 Location: Houma, La. Posts: 11,553	Sounds like you have the idle set way too high. If the idle speed screw does nothing than more than like likely there is not enough slack in the throttle cable or carb slide is in backwards. __________________ 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel
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03-29-2021, 02:17 PM	#2
Oldenslow Join Date: Mar 2020 Posts: 153	I'm not saying there's nothing wrong with your motor -- I'd have to be there to see it for myself -- but it well may be there's nothing wrong with it. A single-cylinder engine is by its nature unbalanced, and although various mechanical features and contrivances serve to reduce vibration in some motors, usually they are going to shake at idle and buzz at speed. On the other hand, something like a 6-cylinder Honda Gold Wing can idle so smoothly you almost have to touch it to make sure it's running. There's a reason single-cylinder engines are often called "thumpers".
	0

04-05-2021, 12:27 PM	#7
franque Join Date: Nov 2017 Location: Marseille, France -> Conakry, Guinea Posts: 1,481	Is the choke on?
	0

04-05-2021, 12:52 PM	#9
ikeus685 Join Date: Sep 2019 Location: Coastal Oregon Posts: 154	Possible problem is that all slack has ben taken out of the throttle cable. Ensure that there is a little wiggle room.
	1

04-05-2021, 03:12 PM	#11
Bruces Join Date: May 2018 Posts: 1,574	The throttle slide might be in backwards
	1

04-05-2021, 07:41 PM	#12
GoldenBoy1704 Join Date: Mar 2021 Posts: 25	Okay guys, I finally figured it out I had bought a third party carb to replace the sock one which I heard was junk. On the third party carb there was a little needle that was stopping the slide from going all the way down. It took me a pretty long time to notice this despite it being a really important detail. It still doesn't run perfectly but at least its better, thanks again everyone for all the help!
	1

04-05-2021, 08:51 PM	#13
idle_purr Join Date: Feb 2021 Location: NY Posts: 218	Not sure if this will help you or not but my father's hawk with 10 miles on it, had this issue and I discovered that there was not enough slack on my throttle cable and whenever I turned left it overstressed the cable. The throttle cable was actually coming out of the carb at about a 15 degree angle. I was able to add more slack by shifting the cable to the front side of the cluster, closer to the key. The cable now comes straight out of the carb and the throttle is smooth as butter. The idle is sporadic, smooth one minute and shaky the next. My father ordered a new carb but it won't be here for about 2 weeks. I assume that will be the resolve we are looking for. Goldenboy are you able to upload a video to youtube of your engine idling after warm up? __________________ NO HILL TOO STEEP NO MUD TOO DEEP The Brozz \| The Hawk Upgrades, Accessories, Etc... Assembly Checklist: Brozz 250 \| Hawk 250 ~idle_purr
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04-05-2021, 09:11 PM	#14
GoldenBoy1704 Join Date: Mar 2021 Posts: 25	Goldenboy are you able to upload a video to youtube of your engine idling after warm up?[/QUOTE] I'll get one tomorrow at around 3:30 pm MST when the field I practice in is free again I have no idea what happened with the quote thing but its not important right now
	0

04-06-2021, 06:20 PM	#15
mtiberio Join Date: Jun 2016 Location: Arlington, VA Posts: 258	one of your motor mount bolts fell out. __________________ 4 time WERA SuperVintage Roadracing National Champion, SCTA Land Speed Record Holder, 3rd AMA Motorcycle GP of Miami
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