hawk 250 top speed
 

from what i have been reading, top speed for most people is around 60 without mods. i weigh 175, have 17 front sprocket and stock (i think 50) rear sprocket and my bike tops out at 48-49 mph. my sons hawk has stock front and rear and his tops just about the same. i have rejetted carb. why are the bike so slow?
thanks!!

How many mile you have on it? Mine woke up after I got a few hundred mile on it .

90 on mine and 150 on my sons.

When you get around the 300 to 400 mile range they really loosen up a run much better and smoother.

Exactly what Jerry said. It takes a few hundred miles for these motors to really wake up. Also, keep a regular eye on those valve clearances during break in.

will do, thanks guys!!!!

You should also go to utube and watch some of the top speed vids of other 250's. I think it will surprise you. These Chinese bikes when probably tuned are not that far off from what brand names are doing.

It is a struggle to get a no mods Hawk to 60 mph. The exhaust system is just too restrictive. But when you get past 500 miles, the engine will free up considerably, assuming you keep your valve clearances within spec. In your case I think you are over geared for an un-broken in engine and bike. You might try a 16 tooth front sprocket, which will give you a little bit more horsepower on the top end. Remember there's a lot of stuff that has to break in in that first 500 miles. Not just the piston rings and bore, there is a gear drive primary, and an all indirect 5 speed transmission that all have to wear in. For your amusement, I once owned a 250 cc AJS CSR with virtually the same engine, but a chain drive primary and a 4 spd tranny with direct drive in 4th. Chain drive has less losses than gear drive, and a direct drive transmission has less power loss than an all indirect drive, and so I got stopped by a CHP for doing 84 mph on that little hummer. He turned me loose when he found out it was a 250. "250's can't go that fast". I didn't argue with him....ARH :ohno:

Its not too hard for a Hawk to hit 60 with nothing but a jetted carb and sprockets. My last Hawk hit 62 with only a mikuni and 17/45 sprockets. It took an exhaust and intake to see beyond that point though. Stock gearing is lucky to see 60 even with bolt ons though. 59mph at 8000rpm lol

I weigh 190 my hawk 250 has 950k I get it up to 64 and it still has a little left. I'm afraid to push it to far. But I think 68mp. And it's all stock. Broke it in gradually and oil changes every 300 miles. Runs great. Really rips for a stock cheap bike. I love it. Lots of people compliment it all the time. I'm starting to see more and more. I love it!!!

I know the hawk 250 has a bigger engine, and is also a bigger bike,
But I think, if I can get my Vader 150 to do 70mph on the freeway, drafting behind another vehicle, I guess it's safe to assume a hawk should be able to do 80mph doing the same.
I would not reduce front sprocket to 16t, but keep the 17t.
Like they say, after about your third oil change (300-500 miles), the bike will open up some.

On the other hand, I would recommend getting rid of the airbox, because the snorkel is a big air restriction, and implodes on itself after a while, further restricting airflow.
Ideally you'd run a pod filter inside the airbox, and just drill out the airbox. That way the pod filter is spared from most mud, rain, or heavier dirt particles.
Also install a less restrictive exhaust, preferably without cat converter.
That way the idle can be lowered.
And most important of all, buy another carburetor, like a PZ30, where you can easily adjust the main jet, to fit the bike.

Those 3 mods, usually net you enough extra power to not only go from a 15 to a 17t front sprocket, but also lower the rear by 5-10 tooth from stock as well, and still make enough power to do 70-75 mph.

The Hawk and all of the bikes like it are aerodynamically challenged. It's not just the fact that they have worse aerodynamics than a house, but that they have a lot of frontal area. A Vader 150 is a much smaller bike in terms of said frontal area, and big frontal area + terrible coefficient of drag = no speed.

A Hawk won't touch 80mph. Not without serious work, and even that is going to come down to the height and weight of the rider on the bike. Most Hawks and Hawk-like bikes top out at 68-70mph, tops - with said mods on the carbureted version being required to achieve it. The DLX makes about the same power as a cab hawk with an exhaust and proper jetting.