Hawk 250 DLX Problems

John Holifield · 10-20-2021, 10:09 AM

I purchased a new DLX recently. From the time I put it together and started it, it has never run right. The place I purchased it from apparently has a tail light warranty.
It has never Idled smoothly and it runs lean judging by the spark plug. The only mods I've done are replacing the spark plug with an iridium one, all the lights to LED along with the blinker module and the sprockets (17 tooth front and 45 tooth rear). I've tested the compression (180 PSI), checked for a vacuum leak, pulled the fuel injector and backflushed it and checked the spray pattern, the stator and rectifier and oxygen sensor all of which seems to check out. The engine light stays on and I have an adapter for my OBII sensor and it has a code of P0505. I've run new oil from the beginning and changed it at 300 miles. I've got my valve clearance set at .003" for the intake and .004" for the exhaust.
I have no Idea of where to go from here. Can anyone help me try to figure this POS out?
I forgot to mention that it will surge sometimes like the piston is trying to seize

**JerryHawk250** · 10-20-2021, 10:16 AM

How many miles do you have on it? If it's fairly new i would give it some time to break in. These engines can be a little tight for the first 500 miles or so.

John Holifield · 10-20-2021, 10:18 AM

Just over 700 miles

tknj99 · 10-20-2021, 10:25 AM

I think the problem sadly with most of the EFI bikes is that they are awfully lean from the factory and there are no readily available tuner or piggy back options unlike the ones you find for the name brand manufacturers. Ofcourse the Chinese carb'd bikes are delivered the same and very lean but can be remedied easily with some carb work.

John Holifield · 10-20-2021, 10:57 AM

I guess I'll just have to live with it and ride it and when it seizes up just trash it and buy a real bike

TxTaoRider · 10-20-2021, 02:18 PM

I dont know if it will help, but some of the guys I know that modify efi cars will run a oxygen sensor extension (also called spark plug anti foulers) that fit between the bung and the o2 sensor. The idea is that it makes the sensor read a little lean and the ecm richens the fuel mixture a little to compensate. For less than 10 bux at the auto parts store I'd give it a try.

**JerryHawk250** · 10-20-2021, 03:28 PM

You can also trick the ECU by adding a resister in the IAT sensor line to make it think the intake temperature is cooler than it really is. Basically that's what a Booster plug does. The booster plus uses a resister and external IAT sensor. You can build your own for about $20.

John Holifield · 10-21-2021, 08:53 AM

Thanks for the suggestions. I'm really frustrated with this bike. BTW how difficult would it be to convert this bike to a carb

10-20-2021, 10:09 AM	#1
John Holifield Join Date: Oct 2021 Posts: 11	Hawk 250 DLX Problems I purchased a new DLX recently. From the time I put it together and started it, it has never run right. The place I purchased it from apparently has a tail light warranty. It has never Idled smoothly and it runs lean judging by the spark plug. The only mods I've done are replacing the spark plug with an iridium one, all the lights to LED along with the blinker module and the sprockets (17 tooth front and 45 tooth rear). I've tested the compression (180 PSI), checked for a vacuum leak, pulled the fuel injector and backflushed it and checked the spray pattern, the stator and rectifier and oxygen sensor all of which seems to check out. The engine light stays on and I have an adapter for my OBII sensor and it has a code of P0505. I've run new oil from the beginning and changed it at 300 miles. I've got my valve clearance set at .003" for the intake and .004" for the exhaust. I have no Idea of where to go from here. Can anyone help me try to figure this POS out? I forgot to mention that it will surge sometimes like the piston is trying to seize
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10-20-2021, 10:16 AM	#2
JerryHawk250 Moderator Join Date: Oct 2016 Location: Houma, La. Posts: 11,574	How many miles do you have on it? If it's fairly new i would give it some time to break in. These engines can be a little tight for the first 500 miles or so. __________________ 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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10-20-2021, 10:25 AM	#4
tknj99 Join Date: Oct 2020 Location: Central VA Posts: 1,258	I think the problem sadly with most of the EFI bikes is that they are awfully lean from the factory and there are no readily available tuner or piggy back options unlike the ones you find for the name brand manufacturers. Ofcourse the Chinese carb'd bikes are delivered the same and very lean but can be remedied easily with some carb work. __________________ 2024 Zuma Storm 150 DLX 2019 Beta 430 RRS 2018 VStrom 1000 XT Former China Bikes: Tao DBX1, Brozz 250, CSC RX4, Titan DLX, Templar X
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10-20-2021, 02:18 PM	#6
TxTaoRider Join Date: Oct 2020 Location: Flower Mound Texas Posts: 904	I dont know if it will help, but some of the guys I know that modify efi cars will run a oxygen sensor extension (also called spark plug anti foulers) that fit between the bung and the o2 sensor. The idea is that it makes the sensor read a little lean and the ecm richens the fuel mixture a little to compensate. For less than 10 bux at the auto parts store I'd give it a try. __________________ 2021 Tao Tbr7 - "Lucille" Mods so far- Brozz swingarm, 21" front rim (Bridgestone Tw302 rear/Dunlop D606 front tires), Digital gauge cluster, pz30b pumper carb, after market hand guards, aftermarket brake and clutch levers, round fold away mirrors, Fly handlebars shortened slightly, 13t front sprocket 2009 Q-link Legacy 250 1982 Suzuki GS1100ES - "Jolene"
	1

10-20-2021, 03:28 PM	#7
JerryHawk250 Moderator Join Date: Oct 2016 Location: Houma, La. Posts: 11,574	You can also trick the ECU by adding a resister in the IAT sensor line to make it think the intake temperature is cooler than it really is. Basically that's what a Booster plug does. The booster plus uses a resister and external IAT sensor. You can build your own for about $20. __________________ 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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10-20-2021, 10:18 AM	#3
John Holifield Join Date: Oct 2021 Posts: 11	Just over 700 miles
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10-20-2021, 10:57 AM	#5
John Holifield Join Date: Oct 2021 Posts: 11	I guess I'll just have to live with it and ride it and when it seizes up just trash it and buy a real bike
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10-21-2021, 08:53 AM	#8
John Holifield Join Date: Oct 2021 Posts: 11	Thanks for the suggestions. I'm really frustrated with this bike. BTW how difficult would it be to convert this bike to a carb
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