Getting a Hawk Running Properly

[Sport Rider]

Hey all! I have completed assembly on my hawk and did the initial firing up. after tinkering with the idle screw a bit I got it to idle after taking it off the choke. now the real fun begins.... NOT! as I told you all when I joined, carbs are a mystery to me. it appears that I'm going to have to peel back the curtain and learn a few things.

Here are the symptoms of how it is running now. it starts after warm with a small twist of the throttle, but not using choke at all. idles fine. revs ok when sitting still. taking it out on the street, it will speed up, but revs don't come all that much and it starts sputtering and losing power.

what's the next steps in troubleshooting and correcting?

[Torgo]

The stock carb is a little clunky, but it should run OK after it warms up. First of all, what exactly are you doing with the choke? How are you setting it?

There are three positions for the butterfly valve: open (bottom), half (middle), and closed (up).

When it's cold out, I have to close it (up) to start. I let it warm up before I drop it down to half, and then fully open it. You only want to operate it when it's at temperature at the open setting (bottom). So hopefully you're stepping through that similarly.

Also, it will not idle by itself as it warms up. After it starts, I have to hold the throttle open a bit. After it warms up a bit, about the same time I start to open the carb, I can then tighten up the idle screw and it'll start idling. Once it's fully warmed up, I'll back the idle off until it idles at what I think is a good RPM. If you turn it too low, it'll kill it, but it doesn't have to be that accurate - you just want a reasonable idle that keeps the engine spinning when you have to stop.

The one nice thing about the stock carb is that the idle adjustment screw is easy to adjust by hand. So you'll figure out how to add and back off the idle after a little bit.

Hope that's a little bit of help - you may not be maximizing the performance with the stock carb, but I've found it to be OK once I got a better feel for its quirks.

[Sport Rider]

Originally Posted by Torgo

The stock carb is a little clunky, but it should run OK after it warms up. First of all, what exactly are you doing with the choke? How are you setting it?

There are three positions for the butterfly valve: open (bottom), half (middle), and closed (up).

When it's cold out, I have to close it (up) to start. I let it warm up before I drop it down to half, and then fully open it. You only want to operate it when it's at temperature at the open setting (bottom). So hopefully you're stepping through that similarly.

Also, it will not idle by itself as it warms up. After it starts, I have to hold the throttle open a bit. After it warms up a bit, about the same time I start to open the carb, I can then tighten up the idle screw and it'll start idling. Once it's fully warmed up, I'll back the idle off until it idles at what I think is a good RPM. If you turn it too low, it'll kill it, but it doesn't have to be that accurate - you just want a reasonable idle that keeps the engine spinning when you have to stop.

The one nice thing about the stock carb is that the idle adjustment screw is easy to adjust by hand. So you'll figure out how to add and back off the idle after a little bit.

Hope that's a little bit of help - you may not be maximizing the performance with the stock carb, but I've found it to be OK once I got a better feel for its quirks.

pretty much followed what you said. I was able to get it off choke once it warmed up some and tinkered with the idle screw to keep it running. once warm and off idle it is losing power in higher rpms, but not through what I think is the mid range. I've seen comments about it being too lean at higher rpms, so this might be that condition being referenced.

the other thing I am noticing is how it comes off idle. it seems to be lagging at the rpms coming back down. I'm familiar with that as perhaps an air leak, so perhaps I'll check the boots to be sure they are good and tight.

open to other thoughts/ideas though! thanks!!!

[jbfla]

Originally Posted by Sport Rider

...
open to other thoughts/ideas though! thanks!!!

Have you checked the valve clearances?

jb

[SpudRider]

I am unfamiliar with the carburetor on your motorcycle. However, you do need to adjust the pilot mixture screw (PMS), if you want you bike to idle properly. You should not need to fiddle with the idle speed screw if you have properly adjusted the pilot mixture screw (PMS).

[wilserchinarider]

Originally Posted by Torgo

The stock carb is a little clunky,
.

This was my experience as well!!! I installed an ebay mikuni, replaced the jets along with a 17T front sprocket and it is a totally different machine. I suspect that the stock carb is jetted very lean to meet emissions.

The stock carb could likely be rejetted as well, but will require drilling out the tamper resistant screws that hold on the carb bottom bowl., but would be $40 cheaper than the mikuni.

[Sport Rider]

Originally Posted by SpudRider

I am unfamiliar with the carburetor on your motorcycle. However, you do need to adjust the pilot mixture screw (PMS), if you want you bike to idle properly. You should not need to fiddle with the idle speed screw if you have properly adjusted the pilot mixture screw (PMS).

any suggestion at what setting to start with? perhaps 1.5 turns? I read in another thread it should not be necessary to go past 2? well....except that rejetting would be a better course.

[wilserchinarider]

Originally Posted by Sport Rider

any suggestion at what setting to start with? perhaps 1.5 turns? I read in another thread it should not be necessary to go past 2? well....except that rejetting would be a better course.

Through my experience with the Hawk, I kinda doubt the pilot mixture screw on the stock carb will give you much if any improvement. As said above, the stock carb is improperly jetted IMO and really needs to be addressed on this bike, much more so than any other china bike I have owned. Including a Zong 200, Lifan GY5, Hi bird, Kinroad, and one Hawk with a bum lean carb! I ran the stock carb on all the bikes except the Hawk, with the stock carb and jets it feels like your dragging an anchor. :(

Swapping or re-jetting is not that difficult, you'll be much happier when you do.

Someone here sourced the jets to fit the stock carb, but I can't recall specifics...or many have done the mikuni swap and were very satisfied.

[Sport Rider]

Originally Posted by wilserchinarider

Through my experience with the Hawk, I kinda doubt the pilot mixture screw on the stock carb will give you much if any improvement. As said above, the stock carb is improperly jetted IMO and really needs to be addressed on this bike, much more so than any other china bike I have owned. Including a Zong 200, Lifan GY5, Hi bird, Kinroad, and one Hawk with a bum lean carb! I ran the stock carb on all the bikes except the Hawk, with the stock carb and jets it feels like your dragging an anchor. :(

Swapping or re-jetting is not that difficult, you'll be much happier when you do.

Someone here sourced the jets to fit the stock carb, but I can't recall specifics...or many have done the mikuni swap and were very satisfied.

I'm going to do the mikuni swap, but just trying to get it running for the time being. hate to have to wait another week + just to ride it.

[SpudRider]

As the others stated, you certainly do need to adjust the carburetor on every bike, and that usually involves changing the jets. However, you shoudl always adjust the pilot mixture screw (PMS) before you change the jets. The bike will not idle properly unless the pilot mixture screw is adjusted properly.

Originally Posted by Sport Rider

any suggestion at what setting to start with? perhaps 1.5 turns? I read in another thread it should not be necessary to go past 2? well....except that rejetting would be a better course.

As I said, I am unfamiliar with this carburetor. Therefore, I would follow the advice given by Weldangrind, who is very familiar with the carburetors for these bikes.

Even if you decide to switch to a Mikuni carb, I strongly suggest you still make your first adjustment to the pilot mixture screw.

[fitze]

Take it to Carolina Fun Machines in Matthews NC. The dealer application says they have to fix it.

Ask Adam Sport Rider, if you put on a new carb you lose warranty.

[BigDoug]

Originally Posted by Sport Rider

Hey all! I have completed assembly on my hawk and did the initial firing up. after tinkering with the idle screw a bit I got it to idle after taking it off the choke. now the real fun begins.... NOT! as I told you all when I joined, carbs are a mystery to me. it appears that I'm going to have to peel back the curtain and learn a few things.

Here are the symptoms of how it is running now. it starts after warm with a small twist of the throttle, but not using choke at all. idles fine. revs ok when sitting still. taking it out on the street, it will speed up, but revs don't come all that much and it starts sputtering and losing power.

what's the next steps in troubleshooting and correcting?

I have a similar problem with one of my two Hawks. Very little power when cold. However once it warms up the bike runs great! Not sure if that is the carb, clutch or something else.....

[fishtime9]

I worked on several different types of dirtbikes, as well as motorcycles in general. However, it is important that you always adjust the pilot screw by screwing it in 1 1/2 turns and than either increase or decrease it, depending on the way the bike idles while its running. But I also read on the forum that these chinese bikes are known to have bad carburetors, in which you would have to get a new one such as the "mikuni" or "qlink" from e-bay. I would highly suggest to just stick with a clone, due to the fact that they are way extremely cheap and do the same good job. Also make sure to clean out the carburetor before installing it! A little clean with the carburetor or break pad cleaner will definitely improve your performance, as well as you never know when manufacturers left medal pieces or debris in there. Please don't hesitate to contact me throughout pm's, if you have any further questions regarding your hawk.

[Sport Rider]

got it running again today and took it for a spin around the block just to try it out. definitely starving for fuel from the way it's running. just wont rev without sputtering. went ahead and ordered a new carb off ebay. will put jets in before I install it. gotta get the jets for it too. will be easier in the long run, I expect.

[Sport Rider]

I ordered this carb for the Hawk:
http://www.ebay.com/itm/360100626734...%3AMEBIDX%3AIT

Can someone tell me which jets I should order from here?
http://www.pjmotorsports.com/mikuni-jets.html