Hawk - Stock Carb
 

so, I've put about 600 miles on my Hawk and the whole time, top speed (even with the 17 tooth front sprocket mod) was around 52. Just realized today that the choke was in the middle position the whole time. DOH! I closed the choke and bam, 58mph on my GPS. Awesome, considering that I'm 6'4" tall and weigh 340!

Only issue is that around half throttle there is a bit of surge / sputter. Crank the throttle just a bit more and it goes away, accelerates strongly. I checked and found no air leaks. Any ideas... not sure that I want to take on the mod with the Mikuni after reading posts here about the trouble getting them dialed in.

The stock carb is so lean that it was nearly jetted right for me in Colorado at around 6,100 feet above sea level. Even so, I switched to the mikuni and it gave me a very noticeable boost in power after getting it set. All I ended up doing was bumping the needle the next clip down.
I think if you're at lower elevation you'll find it's even more worth it, although you can always slot those tamper proof screws and try rejetting the stock one for cheaper.

I'm in Florida, so, elevation is near zero. Maybe I'll have to get someone to help swap out the carb for the Mikuni.

Faulk that's insane you rode 600 miles with the choke at middle setting!! I'm having some of the same problems with my carb. If you find a good, thorough carb tweak tutorial for the hawk let me know!

I'm in Utah, about 5000 elevation but in the mountains higher. What jets and needle setting did you use on the Mikuni?

I actually left all the jets as is, moved the needle to the 2nd clip down from the top, and adjusted the mixture and idle screws after a couple rides up and down the block until it ran strong and idled reliably. I'm not convinced that it's jetted perfectly, but the bike accelerates so much quicker and with no hiccups in the range of the throttle that I didn't worry about messing with the jets themselves.

Ok, I pulled the trigger and ordered the Mikuni and the 115/30 jets. When they come in, I'll let you know how it goes

it will go great, put mine on the other day. it's really nicer.
two turns out on the little screw air thingy..

kind of wish it had the big knob for the idle adjustment like the original, but it's dialed in now.

Same here, the finger adjustable knob was nice. Now I actually have to let the bike warm up for a few minutes before it will idle by itself without needing a little bit of throttle.

You know there is no law stating you can't put the idle adjust screw from your stock carb to you new carb right?lol

Different thread size :/ I was contemplating drilling and tapping the mikuni idle scren and thread a computer thumb screw in with some red loctite.

They sell the correct idle screw and air/fuel screw thumb versions on Ebay and Amazon.



/

Ebay is awesome.

http://www.ebay.com/itm/CNC-Billet-A...lXBAEP&vxp=mtr

Ships from China

Do you know where to get the correct idle adjustment screw?

jb weld a washer in the slot, or just use your thumbnail like i do ... lol

please help
 

Hello fellow flock members! I am a hawk owner myself and am having tuning issues with the current carb + air filter setup so I am going to change it up and dial everything in legit. My airbox wasn't sealed well and my hot air return hose from the engine to box was torn as well so I am just going to overhaul the whole intake system. What model carb and brand did you all use??! I helped a buddy convert his stock dual carb banshee to a single keihin single setup so I know I can do this just need some of your help and its now been a year my hawk has been collecting dust though she has started for me twice and ran for a little both times so i know she has the will to fly just a matter of not giving up with these bikes!

Did your air box/hose connection look like this?

http://www.chinariders.net/attachmen...1&d=1459544527

Mine sure does!

What model year of the Hawk did you purchase, and from whom did you purchase it?

thanks for the quick replies brothers!!! and i bought the 2015 all black..she looked like that until i ripped that rubber tubing to the airbox off because the seal was so poor! Also there was a rubber hosing at the bottom of the airbox that was connected to what i think is the crank case and it was totally torn is that an important hose and what is its job to cool off the crankcase or engine?! It was connected to the airbag right under the big rubber pipe manifold that had the poor seal

I attached a PCV (Positive Crankcase Ventilation) Valve to mine when I removed/ditched the stock air filter and housing for an UNI Pod Filter.

I just went down to the local Auto Parts Stores with the Hose off the engine and found a PCV valve that fit.

Yes, the hose is important. The crankcase vents through that hose into the air box. I suggest you replace that hose, or you risk sucking dirt and/or moisture into the crankcase.

Spud and Azhule you guys are awesome thanks for replying so quick. I knew it was important and no one mentioned what to do about it or seemed to know what I was talking about. Cant wait to post a pic and vid after I get the blackhawk airborne! I was discouraged about registering it in NY and putting much money into it aftermarket but after reading about the SD and VT title transfer option and hearing about the luck others have had with wr450s and yz250s Im sure Ill have no problem and I love my hawk again as much as the day I bought her on my Macbook haha! Gunna throw in a new carb, K&N clamp on filter, look into my crankcase ventilation options, and last but not least a high power L.E.D. or H.I.D. Halo headlight!! Ill post any updates and thanks agin for your help brothers

I finally received the Mikuni 30mm, so, I put the 115/30 jets in, moved the clip on the needle to the middle slot, opened the PMS exactly 2 turns. WOW! I took it for a quick test ride and got to 61mph on the GPS and the bike had more to give.

proper carb and jetting does a lot for a bike!!!

2015, rps

So far I have heard of three, 2015 Hawk bikes with the bad air box/hose connection.

Wolftrax
Farmbath
Blackhawkdown

Hi everyone it's been along time just order a hawk 250 what carb are you guys putting on could you send me a link

Here is what I installed:

http://www.ebay.com/itm/360100626734

I also bought and installed these jets from: http://jetsrus.com/

GENUINE Mikuni pilot jet size 30 ( VM28/486)
GENUINE Mikuni main jet size 115 ( N100.604)

Turn the PMS exactly 2 turns out, voila! (I'm at sea level)

I have swapped the carb on my Hawk as well, but I am having excessive idle issues when cold vs. when hot. If I tune the bike to idle properly while running hot it won't start while cold even with the choke on without giving it gas or having to readjust the idle air screw on the side. I have the standard recommendation jets 30/115 in the bike. I adjusted the fuel mixture screw in the front a bit and it has helped, but I noticed my rpm's take an excessively long time for them to drop. I'm betting I have an air leak, so I'm gonna pick up a bernzomatic to check for leaks, but if anyone has any other ideas why mine behaves so erratically, please let me know.

That screw in the front of the carb is an absolute son out of wedlock to adjust.

If you don't find an air leak, the problem is definitely caused by improper adjustment of the pilot mixture screw (PMS). Always adjust the PMS when the engine is hot, not warm, hot. ;)

Quote of the week! :D

I feel ya man, I am also having lingering idle issues. :grr:

I couldn't get my idle down enough on the 30 jet, and had to move to the 20 to get it even remotely close to being sane. Right now I have to warm it up for quite some time before it will idle on its own, otherwise it just dies. I think im still running rich maybe?

If anyone has recommendations for a bike that will easily choke start, but it need a good 10 minutes of riding before it will idle on its own, id love to hear it.

Also, my bike seems to perform better in the top end and punch when its colder, too rich on the main jet?

Thanks guys!

:thanks:

Have you checked your valves? tight valves will cause an impossible idle condition.
If your WOT (wide open throttle) is better when cold the main jet is too big.

When I had Hawks and Vipers (sold them all) I used OKO / KOSO. Just remember if you buy on Ebay a Mikuni, it will be a knock off and not a TRUE Mikuni, some work good and some are just junk and you will know junk when you have idle and performance problems. Also just keep the carb you have on it and fixit if you are having problems, you don't need a new carb. I can say that when we did carb replacement tests the guys had to hack/refab on the exhaust.

i dont have a hawk, but the storm 250 ... i have the 40/115 jets pms about 1 1/2 turns out ... starts with no choke every time, it idles fine but is a bit richor so it would seem from the black soot on my plate holder, but i still need a better air filter and exhaust, so rich is ok for now and ill see what it does after those two upgrades (was going to do them this week, but going to pick up my 1980 gs850g and get it on the road again)

Yeah, I couldn't find them either. I ordered the one in the link thinking it was the idle screw but apparently it's the mixture screw. Any one know where to get the idle thumb screw for the Mikuni VM26?

What is the best method for removing the tamper proof screws? I saw Motocheez uses a dremel and slots it, but I also found this video https://www.youtube.com/watch?v=0DPcR-dvT50

What did you guys do?

Depending on how the carb is sealed, I either use a Dremel Tool Cutoff Wheel, or a Saw Blade to cut a line and remove with a flat head screwdriver.

Or if the tamper proof screw is "recessed" into the carb... I will bring out my "Alden Grabit/Micro Grabit Pro Extractors"

https://www.amazon.com/Alden-8440P-G.../dp/B001A4CWHO

https://www.amazon.com/Alden-4507P-G.../dp/B000Q60UOO

Alden tools can be found locally at 'Home Improvement' (Lowes, Home Depot, Menards, etc.) type stores for much less than Amazon usually has them for... but Amazon has all the reviews to read :D