Technical Discussion Topics related to Technical Issues

Jetting Carbs

Old 02-10-2013, 07:00 AM
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Jetting Carbs

Just bought an 05 Superhawk. It stumbles/coughs a little at low rpm.
The original owner removed the end baffles from the stock pipes and did nothing to the carbs. I eventually want to put aftermarket pipes on it.
Would jetting the carbs solve the problem I have now? And could I use the same jet kit if I was just going with slipons later?

Thanks in advance.
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Old 02-10-2013, 07:33 AM
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A good start is to read "carb set up" by 8541Hawk which is a sticky in the Technical Discussion subforum. Cleaning your carburettors, changing the pilots to 48's, synching your carburettors or adjusting the pilots may be ways to deal with the problem.
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Old 02-10-2013, 09:58 AM
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You will also need to adjust the TPS another sticky, and remove the PAIR set up, also in the knowledge base.
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Old 02-10-2013, 01:46 PM
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Thanks, I will check the info out.
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Old 02-10-2013, 02:19 PM
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Low RPM

Originally Posted by wtacoma View Post
Just bought an 05 Superhawk. It stumbles/coughs a little at low rpm.
The original owner removed the end baffles from the stock pipes and did nothing to the carbs. I eventually want to put aftermarket pipes on it.
Would jetting the carbs solve the problem I have now? And could I use the same jet kit if I was just going with slipons later?

Thanks in advance.

How low rpm do you mean? From 2d on up it's going to buck if not turning fast enough. Poor intake velocity, too much drive line lash, cam timing ( 107.5* lobe center on intake seems too much to me) or a combination of things but you can't feel good about running a Hawk at low rpm. I can cruise at 2500 r's in 6th but to open the throttle from there is not a good feeling.
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Old 02-10-2013, 03:18 PM
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Originally Posted by HRCA#1 View Post
You will also need to adjust the TPS another sticky, and remove the PAIR set up, also in the knowledge base.
my hawk did that until I adjusted the TPS to 500 ohms. Runs very smooth after adjustment. I did eventually remove the PAIR and that helped also but the TPS caused my hawk stumble and bucking to about 3k to 4k rpm range in 1st and 2nd. gears.
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Old 02-10-2013, 04:13 PM
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TPS can make a big difference.

Also - as with ALL VTR1000's - the TPS must be checked and set to 500 +/- 10 ohms - or low speed cruise smoothness is impossible to attain.
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http://www.factorypro.com/prod_pages/prodh77.html

But as ZXbud says there are lots of things that can cause issues. I would remove the carbs give them a clean and check out the jetting. While the carbs are off you can sort out the screws, slot them or whatever for adjusting the TPS. Make sure the air filter is clean and balance the carbs and you should be good to go.

Basically your bike needs a good tune up. You may as well change the plugs while you at it as well if they have not been changed.

(:-})

[edit]not sure what happened to my factory pro url (link) there but it works[/edit]

Last edited by cybercarl; 02-10-2013 at 04:16 PM.
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Old 02-16-2013, 03:39 AM
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Originally Posted by zxbud View Post
How low rpm do you mean? From 2d on up it's going to buck if not turning fast enough. Poor intake velocity, too much drive line lash, cam timing ( 107.5* lobe center on intake seems too much to me) or a combination of things but you can't feel good about running a Hawk at low rpm. I can cruise at 2500 r's in 6th but to open the throttle from there is not a good feeling.
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Old 02-16-2013, 03:48 AM
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I'm not lugging it. It happens with the clutch in and giving it a little rev to get going.
The bike has low miles and not much TLC. Could just need a good tune up.
Thanks to all for your help.
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Old 02-16-2013, 04:51 AM
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Have you got the Standard air filter still with the aftermarket cans or was the filter changed for K&N or something. If adding aftermarket cans with no baffles, with standard filter there should not be much difference with standard jetting and it should be OK, though would benefit from jetting. If an aftermarket filter was added as well then this would upset the balnce and you would need the jetting adjusted to compensate.

If I was you I would go with Hawks carb set up.
https://www.superhawkforum.com/forum...-set-up-24769/ While you there it gives you the chance to verify what the current jetting is and give the carbs a good clean.

Adjust your TPS. Sorry don't have a link for that but do a search and you will find info.

Balance the carbs and you should be good to go. I suspect the TPS will make a real difference for you.

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Old 02-16-2013, 10:12 AM
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If they pulled the baffles out of the stock cans then your bike is most likely running a bit lean which is what causes your issue. You can try turning your fuel screws out a half to one turn to see if that clears it up. If not try going to the #48 pilot as described in the jetting thread. This seems to make it a little over rich in the pilot circuit but also seems to help attain more of a half step in the main circuit.
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Old 02-16-2013, 09:35 PM
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Originally Posted by GTS View Post
This seems to make it a little over rich in the pilot circuit but also seems to help attain more of a half step in the main circuit.
Not sure where you came up with this information but that is not how things are or work on mine.
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