Choke does nothing

Slofun · 04-20-2021, 01:55 PM

I have an RPS Hawk 250. Valves adjusted to .05mm. Stock carb. No mods at all. I’m at 5100 ft. elevation. With a little throttle it starts right up from cold every time with or without choke. It won’t idle when cold. I let it warm up with a little throttle and then it idles smoothly. I play around with choke settings at cold start and no setting seems to make a difference. It always starts first time with a little throttle. I would like it to start on choke with no throttle and idle fast until it warms up. The choke doesn’t seem to work. Any ideas? And a big thanks for all the great help I’m getting here.

Big Bird · 04-20-2021, 02:47 PM

The nature of being at high altitudes is running richer since the air is less dense. A well tuned bike won't need choke unless it is cold outside. Sounds like your bike is running how it should. Lean epa jetting is about perfect for high altitudes.

Mudflap · 04-20-2021, 06:13 PM

Choke cable may need adjustment. These carbs don't have a fast idle cam so if you want a faster idle you're going to have to turn the screw or twist the throttle.

Skyd · 04-20-2021, 06:57 PM

The hawk is lever operated choke so no cable adjustment there. The idle COULD be set a bit low, I forget what the spec is, but you'd need a Tach to check it...I've always does it by ear...right wrong or indifferent

04-20-2021, 01:55 PM	#1
Slofun Join Date: Mar 2021 Posts: 40	Choke does nothing I have an RPS Hawk 250. Valves adjusted to .05mm. Stock carb. No mods at all. I’m at 5100 ft. elevation. With a little throttle it starts right up from cold every time with or without choke. It won’t idle when cold. I let it warm up with a little throttle and then it idles smoothly. I play around with choke settings at cold start and no setting seems to make a difference. It always starts first time with a little throttle. I would like it to start on choke with no throttle and idle fast until it warms up. The choke doesn’t seem to work. Any ideas? And a big thanks for all the great help I’m getting here.
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04-20-2021, 02:47 PM	#2
Big Bird Join Date: May 2020 Location: California Posts: 169	The nature of being at high altitudes is running richer since the air is less dense. A well tuned bike won't need choke unless it is cold outside. Sounds like your bike is running how it should. Lean epa jetting is about perfect for high altitudes. __________________ 2020 Boom Vader Gen 2 2019 CSC TT250 2021 Kayo Fox 70
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04-20-2021, 06:57 PM	#4
Skyd Join Date: Mar 2021 Location: New Hampshire Posts: 242	The hawk is lever operated choke so no cable adjustment there. The idle COULD be set a bit low, I forget what the spec is, but you'd need a Tach to check it...I've always does it by ear...right wrong or indifferent __________________ 2020 RPS Hawk 250 - Build thread can be found here: http://www.chinariders.net/showthread.php?t=28374 "Do Wheelies and Forget your Feelies" "If vegetarians eat vegetables, what do humanitarians eat?" -unknown
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04-20-2021, 06:13 PM	#3
Mudflap Join Date: Sep 2014 Posts: 1,880	Choke cable may need adjustment. These carbs don't have a fast idle cam so if you want a faster idle you're going to have to turn the screw or twist the throttle.
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