250 hawk for highway use

[K4fireblade]

i got a 250 hawk that will only be ridden on the road and im wanting to know what would be the best sprocket combination for such use . i would like to be able to sustain at least 55mph without the engine reving too high . are there any performance mods that can be done to increase engine power also . thanks any information would be much appreciated

[wilserchinarider]

I also recently purchase a Hawk, IMO it is not a bike suitable for highway use. Regardless of gearing, the bike will only produce enough power to cruise 55 mph at high rpms. Lower gearing will reduce engine speed and engine power, and top speed as well. Someone recently re- geared a hawk lower and lost a couple mph top speed.

Weldandgrind mentioned a 250 top end that could increase HP, perhaps that would help.

My main issue is that on most highways, traffic moves at 70 plus MPH, too fast for a Hawk IMO.

[culcune]

Originally Posted by wilserchinarider

IMO it is not a bike suitable for highway use. Regardless of gearing, the bike will only produce enough power to cruise 55 mph at high rpms. Lower gearing will reduce engine speed and engine power, and top speed as well. Someone recently re- geared a hawk lower and lost a couple mph top speed.

My main issue is that on most highways, traffic moves at 70 plus MPH, too fast for a Hawk IMO.

I wonder what they do to the engines (restrictions and/or timing) to get them to pass EPA? My TMEC 200, stock, will hit about 60 (screaming for mercy), and with my only change being a 48 tooth rear sprocket (had to order from the UK, and that is the smallest manufactured sprocket for the TMEC) I can cruise a 55 to 60 with a lot less screaming. I figure there must be something that can be done/found to get the power back?!

[katoranger]

I think it can be made to run 55. Changing to street tires will help to start. Also improving air flow in and out the engine along with rejetting the carb will gain alittle power.

[katoranger]

My guess is the carb is jetted really lean.

[wilserchinarider]

Originally Posted by katoranger

My guess is the carb is jetted really lean.

I think that is a good guess, mine ran crappy until I untamperproofed the mix screw on the carb and backed it out two turns...running and starting well now

[Louis Angel]

How fast do you need to go? I can not fathom why a Hawk 250 would not be able to run 65+ MPH with a sprocket change. My little Will200 would hit 61 at top end, and IF IF I am correct the 200 had 2 less HP than the 250.
(Too lazy to go look it back up and convert from MN to HP)
But I remember there was about a 2HP difference in one of the bikes I was
comparing before ordering the Will200.

A carb re-jetting would most likely give a performance boost. Not sure
about the Hawk250, but the Will200 ran VERY lean. Like a chalky white spark plug after only 4 weeks lean. 0_0

[K4fireblade]

thanks for the input guys. does anyone know where i can purchase performance parts for the hawk 250 like high performance cdi coil exhaust i have been searching and found nothing thanks

[K4fireblade]

my 250 hawk is running very lean ,and i think that why im only getting 55mph top speed. at wot it is stuttering but if i back off the throttle a bit it continues to accelerate i pulled the plug and its very white. it has zong shen pz30 on it not adjustable ,i have ordered a mikuni 30mm for it any sugestions on jetting would be much apreciated thanks the elevation where i live is 298 ft

[pete]

Originally Posted by K4fireblade

my 250 hawk is running very lean ,and i think that why im only getting 55mph top speed. at wot it is stuttering but if i back off the throttle a bit it continues to accelerate i pulled the plug and its very white. it has zong shen pz30 on it not adjustable ,i have ordered a mikuni 30mm for it any sugestions on jetting would be much apreciated thanks the elevation where i live is 298 ft

Jet it the same as the old carb to get the bike running
& give you a start point....
298 ft is sea level,,
Fuel mixture is the sum total of both pilot & main jets..
alot of people think the pilot jet stops working at higher rpms....
big pilot / small main = easyer cold starting , better low end running
small pilot / big main = harder starting & warm up , better top end running...

So figger out how you use the bike... jet for that...





..

[Louis Angel]

Originally Posted by K4fireblade

................... have ordered a mikuni 30mm for it any sugestions on jetting would be much apreciated thanks the elevation where i live is 298 ft

Actually, the factory jets in the Mikuni 30mm will probably be
just right. The are set to run at sea level. You are not high enough up to need a re-jet really. Unless you need to burn more fuel for more power.
Of course, anything richer than 11.7:1 becomes wasted fuel on a
naturally aspirated engine. So I was taught.
The Mikuni 30mm should be putting you at a 14.9 to 15.1 to 1 Stoichiometric ratio. (Air-Fuel ratio) ---at maxed out top speed WOT---
Just my $0.02

:-D

I bet you will find about 5 extra MPH from the carb change

[K4fireblade]

thanks everyone ill post my results when i get the new carb installed

[Weldangrind]

I've found the stock jets to be too lean at sea level. I normally switch to a 110 main and a 25 slow jet, depending on exhaust and air filter changes.

[K4fireblade]

So far I have installed minkuni 30 mm with 110 main jet. Opened the air box lid up a lil. And changed the front sprocket to 17 tooth. It seems to be running very good top speed of about 60 mph. Anybody know any other mods for performance for this bike?

[Weldangrind]

Save me the time of reading the entire thread again; have you modified the exhaust?