Any info on a Hawk 250 dirt bike.

[Weldangrind]

You're welcome. There is a rev limiter built into the CDI, but I wouldn't want to defeat it. You can buy a no-rev limit CDI, but these pushrod motors have only so much potential. Believe it or not, there is only one cam lobe, and it bumps both valves. That means that neither valve can be optimized for lift or duration, but it's a wonderful motor for low end grunt and longevity.

Since most of these machines are lean from the factory, you're likely just running out of fuel at the top end. Fattening it by two sizes will likely produce results.

The Mikuni will have the wrong jets for your application, but they're cheap and plentiful. It will have a 100 main and a 20 slow jet. I'd recommend a 110 main, and at least a 25 slow if you're at any amount of elevation. If you're at sea level, try a 30 slow jet.

[Weldangrind]

Awesome screen name, BTW.

[katoranger]

I would also replace the sparkplug with an NGK.

[culcune]

Originally Posted by katoranger

I would also replace the sparkplug with an NGK.

X2 ^^

I can't remember if you wrote you changed it, but the plug is an easy, low-cost part.

I should also mention, try some of the Bashan 250 enduro threads from about 2 or 3 months ago. Those guys had problems with their gas leaking out (all over them) on throttle, and they were looking into cap/pressure issues. Not sure if they ever got their problem resolved, but if they did, you can see what they did, or ask them. Your bike might incorporate the same engine as theirs, if not being manufactured by the same company (it's a Chinese thing playing 'who is the manufacturer')

[culcune]

Look through these threads

http://chinariders.net/showthread.php?t=13950

http://chinariders.net/showthread.php?t=14256

http://chinariders.net/showthread.php?t=13928

Again, not sure if the bikes are related, or at least the engines, but I remember there being a tank/gas cap issue in a couple of the threads.

[Gr8rcher]

Stock Mikuni jets seem to be working well for me in Fort Worth. But I am trail riding my Apollo 250 with a similar engine. the new carb made a huge difference on my bike.

Also adjust the valve lash, and replace the spark plug.

[Sub Dude]

Thanks for all the information and suggestions. I just ordered a new Mikuni carb and NGK plug today. I will let you know how it works out.

[midlifemx5]

I just Bought 2 of these myself (still waiting for them to arrive.) I will be following this thread and many others I am sure.

[midlifemx5]

I did as much research as I could before my purchase and the info I have is that it is a 229 cc engine and the basic bike is a Yamaha TT 225 clone

[Weldangrind]

Welcome! The engine could be 223 or 229, but it doesn't make much difference. When you receive your bikes, please start a thread and show us pics.

[newtoenduro]

Originally Posted by sub dude

just bought this hawk 250 dirt bike in arlington texas and wanted to get more information about it. The bike is from the chongqing haosen manufacturing company and has a 167fmm 223cc engine. Is this manufacturer known for quality products, i found very little information about them? Are all of the 223cc honda clone engines basically the same except for the side covers? I had the retailer replace the oil with synthetic oil and drove the 50 miles home then replaced the oil again. I found very little debris in the oil screen and the used oil was dark but nothing i did not expect. I put another 100 road miles on it the next day plus 5 off-road hill and sand miles. So far the only issue i have with the bike is it only will do 50 mph and acts like it is starving for fuel or has a rev limiter kicking in. Lower speed but hard acceleration will also exhibit the same behavior. If the manual is to be believed the bike should do 60 mph. I have not run it with the fuel cap removed to verify proper tank venting yet but wanted to hear other ideas of what i could check the next time i take it out. Thanks for your help.

what size did you switch to? I am having the ame problem

[967corey]

Hello all !! I recently bought a 2015 haosen hs250y-a hawk 250 from apscusa.com . I have been reading everyone's threds . I'm having similar issue's I'm only getting 55 to maby 60 mph all the way wound out ! And it feels like its not getting enuff fule . I found a like to eBay here to a new makuni carb . definitely gonna get one of those , I think that should help a lot . my other issue is I'm trying to find a place to get new front and rear sprockets the rear had a 53 tooth not shure on the front sprocket yet I need to pull the front cover off and count the teeth . I'm trying to get a little more top end speed with out reving the hell out of the thing ! Any help or suggestions would be greatly appreciated !! Thanks

[967corey]

Here are some pictures of my 2015 hawk .

[Weldangrind]

Welcome, Corey!

The Mikuni will only be a benefit if you plan mods to the air cleaner or exhaust. Otherwise, if it starts and runs well, leave that part alone.

The sprockets are the biggest issue. 53 is really low; let us know what size your front sprocket is.

[Weldangrind]

Sweet bike! Please start a new thread on it.