Hawk 2020 will NOT go over 50 mph!!?

BakedOregonian · 04-17-2021, 08:13 PM

I swapped the sprockets for the recommended tooth count... I completely removed my rear brake to eliminate brake drag and she will NOT go over 50. WTH?!

Bruces · 04-17-2021, 08:37 PM

How many miles on it ? What have you done with it in terms of valve adj ,carb set up etc ?

BakedOregonian · 04-18-2021, 12:07 AM

She's EFI, so no carb and she has about 50 miles.

Skyd · 04-18-2021, 11:01 AM

When you say it won't go over 50, are you out of engine? Like is it 5th gear WOT and that's all she has or is it more like something holding it back?

BakedOregonian · 04-18-2021, 11:55 AM

She's WOT and has nothing left. I have no clue what's going on.

Skyd · 04-18-2021, 12:28 PM

what are you running for gearing? You say recommended but it's dependent on what you want to do...for trials only recommended might be the stock 15/50 which I think puts you about where you are for top speed. Also, I'm told these speedos are quite inaccurate...you could try a GPS speedometer on your phone and see what you're getting.

I'm not familiar with EFI on bikes at all, never had one, and so I can't speak to any issues there might be there with mapping or anything. I'm sure someone better versed in that will chime in here soon.

BakedOregonian · 04-18-2021, 12:48 PM

17:45 gear ratio. That's a great idea about the speedo but I am required to take my Hawk to get to work and people are definitely easily passing me. I'm certain there's something going on.

Bill Hilly · 04-18-2021, 01:12 PM

How many rpms do you build in 4th before shifting to 5th? when you adjusted your valves are you 100% sure you were not 180 degrees off on your crank? The cam only spins at half the rate as the crank.. Are you sure you used the right feeler gauge ,some have both metric,and SAE on the same blade. Did you snug the lock nuts up on the valve adjustment screws without letting them turn the screw ?

BakedOregonian · 04-18-2021, 01:34 PM

I've messed with the rpm's before shifting in a multitude of ways and she just has nothing after 50 mph. Thank you for your help!

Let me ask, I was under the impression that if I was 180 off top center then she wouldn't start at all. Is that not true?

I was certain about my feeler gauge until you said something about it lol, I will be sure to double check! To be clear, adjusting the valves can affect speed that much?

I will check everything again. Thank you so much!

franque · 04-18-2021, 04:58 PM

Check the valves on an engine that has cooled off overnight. If it's not that, since it's FI, I think it's possible you have a blockage somewhere; my suggestion would be to get a propane torch on the cat, in case there is anything restricting flow, and get it red, or nearly red hot so that the crap that's potentially causing a restriction can be burned out.

04-17-2021, 08:13 PM	#1
BakedOregonian Join Date: Apr 2021 Location: Oregon Posts: 64	Hawk 2020 will NOT go over 50 mph!!? I swapped the sprockets for the recommended tooth count... I completely removed my rear brake to eliminate brake drag and she will NOT go over 50. WTH?!
	0

04-18-2021, 11:01 AM	#4
Skyd Join Date: Mar 2021 Location: New Hampshire Posts: 242	When you say it won't go over 50, are you out of engine? Like is it 5th gear WOT and that's all she has or is it more like something holding it back? __________________ 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
	0

04-18-2021, 12:28 PM	#6
Skyd Join Date: Mar 2021 Location: New Hampshire Posts: 242	what are you running for gearing? You say recommended but it's dependent on what you want to do...for trials only recommended might be the stock 15/50 which I think puts you about where you are for top speed. Also, I'm told these speedos are quite inaccurate...you could try a GPS speedometer on your phone and see what you're getting. I'm not familiar with EFI on bikes at all, never had one, and so I can't speak to any issues there might be there with mapping or anything. I'm sure someone better versed in that will chime in here soon. __________________ 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
	0

04-17-2021, 08:37 PM	#2
Bruces Join Date: May 2018 Posts: 1,655	How many miles on it ? What have you done with it in terms of valve adj ,carb set up etc ?
	0

04-18-2021, 12:07 AM	#3
BakedOregonian Join Date: Apr 2021 Location: Oregon Posts: 64	She's EFI, so no carb and she has about 50 miles.
	0

04-18-2021, 11:55 AM	#5
BakedOregonian Join Date: Apr 2021 Location: Oregon Posts: 64	She's WOT and has nothing left. I have no clue what's going on.
	0

04-18-2021, 12:48 PM	#7
BakedOregonian Join Date: Apr 2021 Location: Oregon Posts: 64	17:45 gear ratio. That's a great idea about the speedo but I am required to take my Hawk to get to work and people are definitely easily passing me. I'm certain there's something going on.
	0

04-18-2021, 01:12 PM	#8
Bill Hilly Join Date: Feb 2021 Posts: 1,005	How many rpms do you build in 4th before shifting to 5th? when you adjusted your valves are you 100% sure you were not 180 degrees off on your crank? The cam only spins at half the rate as the crank.. Are you sure you used the right feeler gauge ,some have both metric,and SAE on the same blade. Did you snug the lock nuts up on the valve adjustment screws without letting them turn the screw ?
	0

04-18-2021, 01:34 PM	#9
BakedOregonian Join Date: Apr 2021 Location: Oregon Posts: 64	I've messed with the rpm's before shifting in a multitude of ways and she just has nothing after 50 mph. Thank you for your help! Let me ask, I was under the impression that if I was 180 off top center then she wouldn't start at all. Is that not true? I was certain about my feeler gauge until you said something about it lol, I will be sure to double check! To be clear, adjusting the valves can affect speed that much? I will check everything again. Thank you so much!
	0

04-18-2021, 04:58 PM	#10
franque Join Date: Nov 2017 Location: Marseille, France -> Conakry, Guinea Posts: 1,481	Check the valves on an engine that has cooled off overnight. If it's not that, since it's FI, I think it's possible you have a blockage somewhere; my suggestion would be to get a propane torch on the cat, in case there is anything restricting flow, and get it red, or nearly red hot so that the crap that's potentially causing a restriction can be burned out.
	1