Hawk 250 carb tuning problems, please help

SeanM76 · 11-12-2017, 06:33 PM

Ok so today I ventured into the world of carb tuning. Bare in mind with me that I've never worked on a carb before.

So I watched several videos before beginning. I wanted to go in with as much knowledge on what I'm doing as possible. I probably watched 15 videos on the subject including motocheez (who's quickly becoming my idol when it comes to information about this bike).

On to the job at hand.

I get the carb off without problem, I'm experienced at working on cars and turning a wrench. I take apart the housing where the throttle cable goes in and quickly take it apart, I got two washers on that needle just like motocheez said. I get the cable and spring connected to the black piece again without much problem, so far, I'm doing well.

Next I grab my dremel since this is going good I'm feeling good, I notch out the three screws... perfect. The housing comes off and I see the main key sitting there ready to be replaced. I unscrew it and, first problem I ran into, it doesn't look like the jet I bough! Watch a few more videos and realize the jet is two piece, I have to remove just the head and replace it. Phew! Got it. Now, that pesky idol screw under the little plastic cap. After picking at it unsuccessfully for 15 minutes I grabbed my drill and a tiny bit, screwed i to the plastic a bit and pulled, it popped right out. I didn't pay attention to where it was but I put it all the way in, then backed it out 1 1/2 turns.

Then I put it all back together. Easy Peazy. I'm excited about how well it went I enjoyed a nice victory cigar. As it turns out. The celebration came to early.

I started the bike up and she isn't the same bike. She's now a growling beast throwing a shit ton of smoke like you wouldn't believe and shaking the whole garage with her roar. She has to be idleing around 7k, my neighbors Harley would have been impressed with the sound. Then I see smoke from the rear end (I'm standing on the "drivers side" of her if you will, so I walk around to see what the smoke is from.... her exhaust is cherry red, and the silver exhaust cover is melting off (side note, where can I buy new plastics?). Quickly I shut it down and let it cool down.

Now I take it back apart. Listen for anyone doing this their first time, there is a small piece of misinformation in the videos about doing the carb adjustment... then you put in the black piece and throttle cable assembly, the videos I watched said "it only goes in one way", is misleading. What they mean is, it only goes ALL THE WAY IN, one way. Because I was able to get it in there and screwed together I thought I had it right. I was wrong. It was backwards and making it run like a bat out of hell.

So while I had it off I took off one of the washers (I have one washer on it still), it's pretty thick so it's probably a washer and a half or so compared to what it looked like motocheez used in his video. I have a 115 jet, and I have the throttle screw 1 1/2 turns out. Get it all back together. Now she's still more powerful sounding that original, but the idol is about where it should be. I think we're good.

Wrong

I take it out for a test drive, now let me tell you, I did this because at about 75% throttle she was bogging out a bit, sputtering.... now she still does that, but instead of 75% throttle she's doing it at about 50%.

Someone, for the love of God, tell me what to do from here? 3 hours into this project that I thought would take 30 minutes, and I'm frustrated because of my lack of knowledge of carbs is leaving me not knowing what to do from here. So, here I am, doing the only thing I know how to do at this point, seeing what information anyone here can possibly give me on this.

Thanks in advance for any help on the subject!!

**JerryHawk250** · 11-12-2017, 06:55 PM

Check to make sure the choke is off.

SeanM76 · 11-12-2017, 06:57 PM

Yup, choke is off. It was also almost impossible to start, even with the choke on.

**JerryHawk250** · 11-12-2017, 06:58 PM

If you still have the stock exhaust you may be running rich
Try a 110.

Megadan · 11-12-2017, 07:06 PM

I agree. If this is a stock bike go to a 110 main

Tip for carb tuning. 1 change at a time. I have a lot of experience with carbs and I still do one change at a time. It really helps track what effect there was at the given throttle range.

Oh, and when you go to swap jets check the float height as well. Quick and dirty method. Hold the carb upside down and the float seams should be level with the bowl flange.

SeanM76 · 11-12-2017, 07:25 PM

Would that make it smell like gas? It's putting out a heavy gassy odor

Sullybiker · 11-12-2017, 07:50 PM

Quote:

Originally Posted by SeanM76

Would that make it smell like gas? It's putting out a heavy gassy odor

Unburnt hydrocarbons

Yes, that would do it.

Megadan · 11-12-2017, 09:46 PM

You might also find that the 110 is a bit rich, but it should at least run decently. Plus with the colder weather it may run better. Once it warms back up it would be worth checking again.

Also, check to make sure the needle is securely seated in the throttle barrel. If it is loose and gets hung up and doesnt seat fully, you will get really inconsistent fueling between 1/4 and 3/4 throttle.

Another recommendation is to use genuine jets and not cheap ones from kits on amazon and ebay. Most cheap jets are not always sized consistently, or as I discovered, mis labled. I got a kit that came with two 100 jets, and one was actually a 110.

SeanM76 · 11-12-2017, 10:45 PM

Call me crazy.... but out of curiosity, do they make a suitable fuel injection system for this? Throttle body I'm thinking? Or is that hoping to much lol?

Megadan · 11-13-2017, 02:01 AM

Quote:

Originally Posted by SeanM76

Call me crazy.... but out of curiosity, do they make a suitable fuel injection system for this? Throttle body I'm thinking? Or is that hoping to much lol?

Sure there is efi out there, but 2 things. You would probably want to upgrade the charging system and it is universal. Plus, you would have to tune efi from scratch. Think carb tuning is complicated? LOL.

Carbs arent all that bad. Once you dial in the tuning, the worst thing you have to possibly deal with is changing jets for extreme altitude or temp swings. I always tune air cooled bikes to be a tad rich on hot days, which means during colder temps they are usually more accurately tuned, only needing a small main jet increase after the temps drop 50 degrees or more.

SeanM76 · 11-13-2017, 09:59 AM

Ok here's where I am now:

Woke up this morning to a puddle of gas on the floor under the bike.
Took it all apart again. She is now at 110 jet, no washers on the pin at all, idle screw is 1.75 turns out. High end is maybe a hair off but I'm getting full throttle for the most part now. Starting the bike is harder than stock though. She wants to stall out like crazy. For the first two minutes I have to hold the throttle open a bit (the thumb screw adjustment for idle I have all the way in when starting as well).

The only place she bogs now is between 25% and 35% throttle and only in first gear (which makes no sense to me, why doesn't it do it there no matter what gear it's in?). Any tips on getting rid of that one little big spot? It bogs there once maybe twice, then continues on like it didn't happen. Just seem to have to get it past that spot.

**JerryHawk250** · 11-13-2017, 10:22 AM

Quote:

Originally Posted by SeanM76

Ok here's where I am now:

Woke up this morning to a puddle of gas on the floor under the bike.
Took it all apart again. She is now at 110 jet, no washers on the pin at all, idle screw is 1.75 turns out. High end is maybe a hair off but I'm getting full throttle for the most part now. Starting the bike is harder than stock though. She wants to stall out like crazy. For the first two minutes I have to hold the throttle open a bit (the thumb screw adjustment for idle I have all the way in when starting as well).

The only place she bogs now is between 25% and 35% throttle and only in first gear (which makes no sense to me, why doesn't it do it there no matter what gear it's in?). Any tips on getting rid of that one little big spot? It bogs there once maybe twice, then continues on like it didn't happen. Just seem to have to get it past that spot.

Yes, you will need to shim the needle to lift it.

Sullybiker · 11-13-2017, 10:23 AM

Quote:

Originally Posted by SeanM76

Ok here's where I am now:

Woke up this morning to a puddle of gas on the floor under the bike.
Took it all apart again. She is now at 110 jet, no washers on the pin at all, idle screw is 1.75 turns out. High end is maybe a hair off but I'm getting full throttle for the most part now. Starting the bike is harder than stock though. She wants to stall out like crazy. For the first two minutes I have to hold the throttle open a bit (the thumb screw adjustment for idle I have all the way in when starting as well).

The only place she bogs now is between 25% and 35% throttle and only in first gear (which makes no sense to me, why doesn't it do it there no matter what gear it's in?). Any tips on getting rid of that one little big spot? It bogs there once maybe twice, then continues on like it didn't happen. Just seem to have to get it past that spot.

It's not doing it just in first gear, it's likely that it is in first gear that you're using that range of throttle (moving off, rather than changing up).

I had a similar issue. Your needle clip needs to be raised by one slot (or how ever many washer equivalents).

**JerryHawk250** · 11-13-2017, 10:25 AM

The puddle of gas on the floor tells me the either the float needs adjusting or the float valve is not sealing off.

SeanM76 · 11-13-2017, 10:57 AM

I was wondering if I should shim the needle or if I should change the smaller jet. I don't know what came stock there but I've heard maybe a 27.5 or 30 would be better. I'll try shimming again when I get home and see how that goes with the 110 in there.

How do I adjust the float and what am I looking for in terms of how it should be adjusted?

11-12-2017, 06:33 PM	#1
SeanM76 Join Date: Sep 2017 Location: Toledo, Ohio Posts: 19	Hawk 250 carb tuning problems, please help Ok so today I ventured into the world of carb tuning. Bare in mind with me that I've never worked on a carb before. So I watched several videos before beginning. I wanted to go in with as much knowledge on what I'm doing as possible. I probably watched 15 videos on the subject including motocheez (who's quickly becoming my idol when it comes to information about this bike). On to the job at hand. I get the carb off without problem, I'm experienced at working on cars and turning a wrench. I take apart the housing where the throttle cable goes in and quickly take it apart, I got two washers on that needle just like motocheez said. I get the cable and spring connected to the black piece again without much problem, so far, I'm doing well. Next I grab my dremel since this is going good I'm feeling good, I notch out the three screws... perfect. The housing comes off and I see the main key sitting there ready to be replaced. I unscrew it and, first problem I ran into, it doesn't look like the jet I bough! Watch a few more videos and realize the jet is two piece, I have to remove just the head and replace it. Phew! Got it. Now, that pesky idol screw under the little plastic cap. After picking at it unsuccessfully for 15 minutes I grabbed my drill and a tiny bit, screwed i to the plastic a bit and pulled, it popped right out. I didn't pay attention to where it was but I put it all the way in, then backed it out 1 1/2 turns. Then I put it all back together. Easy Peazy. I'm excited about how well it went I enjoyed a nice victory cigar. As it turns out. The celebration came to early. I started the bike up and she isn't the same bike. She's now a growling beast throwing a shit ton of smoke like you wouldn't believe and shaking the whole garage with her roar. She has to be idleing around 7k, my neighbors Harley would have been impressed with the sound. Then I see smoke from the rear end (I'm standing on the "drivers side" of her if you will, so I walk around to see what the smoke is from.... her exhaust is cherry red, and the silver exhaust cover is melting off (side note, where can I buy new plastics?). Quickly I shut it down and let it cool down. Now I take it back apart. Listen for anyone doing this their first time, there is a small piece of misinformation in the videos about doing the carb adjustment... then you put in the black piece and throttle cable assembly, the videos I watched said "it only goes in one way", is misleading. What they mean is, it only goes ALL THE WAY IN, one way. Because I was able to get it in there and screwed together I thought I had it right. I was wrong. It was backwards and making it run like a bat out of hell. So while I had it off I took off one of the washers (I have one washer on it still), it's pretty thick so it's probably a washer and a half or so compared to what it looked like motocheez used in his video. I have a 115 jet, and I have the throttle screw 1 1/2 turns out. Get it all back together. Now she's still more powerful sounding that original, but the idol is about where it should be. I think we're good. Wrong I take it out for a test drive, now let me tell you, I did this because at about 75% throttle she was bogging out a bit, sputtering.... now she still does that, but instead of 75% throttle she's doing it at about 50%. Someone, for the love of God, tell me what to do from here? 3 hours into this project that I thought would take 30 minutes, and I'm frustrated because of my lack of knowledge of carbs is leaving me not knowing what to do from here. So, here I am, doing the only thing I know how to do at this point, seeing what information anyone here can possibly give me on this. Thanks in advance for any help on the subject!!
	0

11-12-2017, 06:55 PM	#2
JerryHawk250 Moderator Join Date: Oct 2016 Location: Houma, La. Posts: 11,564	Check to make sure the choke is off. __________________ 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
	0

11-12-2017, 06:58 PM	#4
JerryHawk250 Moderator Join Date: Oct 2016 Location: Houma, La. Posts: 11,564	If you still have the stock exhaust you may be running rich Try a 110. __________________ 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
	1

11-12-2017, 07:06 PM	#5
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,028	I agree. If this is a stock bike go to a 110 main Tip for carb tuning. 1 change at a time. I have a lot of experience with carbs and I still do one change at a time. It really helps track what effect there was at the given throttle range. Oh, and when you go to swap jets check the float height as well. Quick and dirty method. Hold the carb upside down and the float seams should be level with the bowl flange. __________________ 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
	0

11-12-2017, 09:46 PM	#8
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,028	You might also find that the 110 is a bit rich, but it should at least run decently. Plus with the colder weather it may run better. Once it warms back up it would be worth checking again. Also, check to make sure the needle is securely seated in the throttle barrel. If it is loose and gets hung up and doesnt seat fully, you will get really inconsistent fueling between 1/4 and 3/4 throttle. Another recommendation is to use genuine jets and not cheap ones from kits on amazon and ebay. Most cheap jets are not always sized consistently, or as I discovered, mis labled. I got a kit that came with two 100 jets, and one was actually a 110. __________________ 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
	0

11-12-2017, 06:57 PM	#3
SeanM76 Join Date: Sep 2017 Location: Toledo, Ohio Posts: 19	Yup, choke is off. It was also almost impossible to start, even with the choke on.
	0

11-12-2017, 07:25 PM	#6
SeanM76 Join Date: Sep 2017 Location: Toledo, Ohio Posts: 19	Would that make it smell like gas? It's putting out a heavy gassy odor
	0

11-12-2017, 10:45 PM	#9
SeanM76 Join Date: Sep 2017 Location: Toledo, Ohio Posts: 19	Call me crazy.... but out of curiosity, do they make a suitable fuel injection system for this? Throttle body I'm thinking? Or is that hoping to much lol?
	0

11-13-2017, 09:59 AM	#11
SeanM76 Join Date: Sep 2017 Location: Toledo, Ohio Posts: 19	Ok here's where I am now: Woke up this morning to a puddle of gas on the floor under the bike. Took it all apart again. She is now at 110 jet, no washers on the pin at all, idle screw is 1.75 turns out. High end is maybe a hair off but I'm getting full throttle for the most part now. Starting the bike is harder than stock though. She wants to stall out like crazy. For the first two minutes I have to hold the throttle open a bit (the thumb screw adjustment for idle I have all the way in when starting as well). The only place she bogs now is between 25% and 35% throttle and only in first gear (which makes no sense to me, why doesn't it do it there no matter what gear it's in?). Any tips on getting rid of that one little big spot? It bogs there once maybe twice, then continues on like it didn't happen. Just seem to have to get it past that spot.
	0

11-13-2017, 10:25 AM	#14
JerryHawk250 Moderator Join Date: Oct 2016 Location: Houma, La. Posts: 11,564	The puddle of gas on the floor tells me the either the float needs adjusting or the float valve is not sealing off. __________________ 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
	1

11-13-2017, 10:57 AM	#15
SeanM76 Join Date: Sep 2017 Location: Toledo, Ohio Posts: 19	I was wondering if I should shim the needle or if I should change the smaller jet. I don't know what came stock there but I've heard maybe a 27.5 or 30 would be better. I'll try shimming again when I get home and see how that goes with the 110 in there. How do I adjust the float and what am I looking for in terms of how it should be adjusted?
	0