Hawk's Peak RPM

Newwood · 10-08-2020, 08:54 PM

Did some searching and could not find a thread that answers my question so...

I have a 2017 Hawk, about 6500 miles on it. 17/45 sprockets, stock carb with 110 main jet (runs rich with a 115) needle is shimmed with two washers. Stock de-catted exhaust with a several holes poked into the baffle and cleaned up welds at the header. Good Plug, stock airbox opened up for more flow. Valves are good. In other words pretty much all of the "standard" mods.

My question is peak rpms. In the first 4 gears it will walk right to 8000-8100 without a problem. In 5th it tops out right around 7000- 7100 and the it falls flat. Even on a good downhill I am lucky to see 7200. As a reult my top speed is 62 max. I can get 55-56 in 4th at 8000. I don't really want to go over 60 but would like to run 57-59 with out going WOT.

What am I missing? Thanks in advance!

**JerryHawk250** · 10-09-2020, 07:38 AM

The Hawk engine Max HP peaks out around the 7000 rpm range. Swap out the rear sprocket to a 40 tooth to drop down those rpm's and WOT and you be able to cruise around at 60 to 65 mph.

Newwood · 10-09-2020, 07:03 PM

Thanks JerryHawk, I may have to give that a try.

Deckard_Cain · 10-10-2020, 10:23 AM

You're likely hitting that "wall" in 5th gear because the stock head doesn't flow enough air. The engine simply runs out of breathing room to continue making power.

10-08-2020, 08:54 PM	#1
Newwood Join Date: Mar 2017 Location: Merrill, WI Posts: 20	Hawk's Peak RPM Did some searching and could not find a thread that answers my question so... I have a 2017 Hawk, about 6500 miles on it. 17/45 sprockets, stock carb with 110 main jet (runs rich with a 115) needle is shimmed with two washers. Stock de-catted exhaust with a several holes poked into the baffle and cleaned up welds at the header. Good Plug, stock airbox opened up for more flow. Valves are good. In other words pretty much all of the "standard" mods. My question is peak rpms. In the first 4 gears it will walk right to 8000-8100 without a problem. In 5th it tops out right around 7000- 7100 and the it falls flat. Even on a good downhill I am lucky to see 7200. As a reult my top speed is 62 max. I can get 55-56 in 4th at 8000. I don't really want to go over 60 but would like to run 57-59 with out going WOT. What am I missing? Thanks in advance!
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10-09-2020, 07:38 AM	#2
JerryHawk250 Moderator Join Date: Oct 2016 Location: Houma, La. Posts: 11,555	The Hawk engine Max HP peaks out around the 7000 rpm range. Swap out the rear sprocket to a 40 tooth to drop down those rpm's and WOT and you be able to cruise around at 60 to 65 mph. __________________ 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel
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10-09-2020, 07:03 PM	#3
Newwood Join Date: Mar 2017 Location: Merrill, WI Posts: 20	Thanks JerryHawk, I may have to give that a try.
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10-10-2020, 10:23 AM	#4
Deckard_Cain Join Date: Aug 2019 Location: Bay City, MI Posts: 397	You're likely hitting that "wall" in 5th gear because the stock head doesn't flow enough air. The engine simply runs out of breathing room to continue making power.
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