Technical Discussion Topics related to Technical Issues

Jetting Carbs

Thread Tools
 
Search this Thread
 
Old Feb 10, 2013 | 07:00 AM
  #1  
wtacoma's Avatar
Thread Starter
Junior Member
Squid
 
Joined: Feb 2013
Posts: 13
wtacoma is on a distinguished road
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.
Old Feb 10, 2013 | 07:33 AM
  #2  
comedo's Avatar
Senior Member
SuperSport
 
Joined: Nov 2007
Posts: 807
From: Hamilton, Ontario, Canada
comedo is on a distinguished road
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.
Old Feb 10, 2013 | 09:58 AM
  #3  
HRCA#1's Avatar
Senior Member
SuperBike
 
Joined: Oct 2007
Posts: 1,082
From: Menifee, CA
HRCA#1 is on a distinguished road
You will also need to adjust the TPS another sticky, and remove the PAIR set up, also in the knowledge base.
Old Feb 10, 2013 | 01:46 PM
  #4  
wtacoma's Avatar
Thread Starter
Junior Member
Squid
 
Joined: Feb 2013
Posts: 13
wtacoma is on a distinguished road
Thanks, I will check the info out.
Old Feb 10, 2013 | 02:19 PM
  #5  
zxbud's Avatar
Senior Member
Superstock
 
Joined: Oct 2011
Posts: 273
From: Pompano Beach, Fl.
zxbud is on a distinguished road
Low RPM

Originally Posted by wtacoma
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.
Old Feb 10, 2013 | 03:18 PM
  #6  
twist's Avatar
Senior Member
SuperSport
 
Joined: Jul 2012
Posts: 582
From: Santa Fe, New Mexico
twist is on a distinguished road
Originally Posted by HRCA#1
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.
Old Feb 10, 2013 | 04:13 PM
  #7  
cybercarl's Avatar
Senior Member
Superstock
 
Joined: May 2012
Posts: 397
From: UK
cybercarl is on a distinguished road
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.
</title> <meta name="Microsoft Border" content="none"> <style type="text/css"> .style1 { text-align: center; } </style> </head> <body text="#C0C0C0" bgcolor="#000000" style="font-family: Arial; font-size: 10pt"> <div align="center"> <table border="1"

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; Feb 10, 2013 at 04:16 PM.
Old Feb 16, 2013 | 03:39 AM
  #8  
wtacoma's Avatar
Thread Starter
Junior Member
Squid
 
Joined: Feb 2013
Posts: 13
wtacoma is on a distinguished road
Originally Posted by zxbud
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.
Old Feb 16, 2013 | 03:48 AM
  #9  
wtacoma's Avatar
Thread Starter
Junior Member
Squid
 
Joined: Feb 2013
Posts: 13
wtacoma is on a distinguished road
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.
Old Feb 16, 2013 | 04:51 AM
  #10  
cybercarl's Avatar
Senior Member
Superstock
 
Joined: May 2012
Posts: 397
From: UK
cybercarl is on a distinguished road
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.

(:-})
Old Feb 16, 2013 | 10:12 AM
  #11  
GTS's Avatar
GTS
Seasoned tech
SuperSport
 
Joined: Apr 2012
Posts: 576
From: Issaquah, WA
GTS is on a distinguished road
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.
Old Feb 16, 2013 | 09:35 PM
  #12  
8541Hawk's Avatar
Banned
MotoGP
 
Joined: Aug 2007
Posts: 5,942
From: Lake View Terrace, CA
8541Hawk will become famous soon enough
Originally Posted by GTS
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.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
YellowHawk
Technical Discussion
9
Mar 26, 2007 07:06 AM
Speed_Demon
Technical Discussion
9
Feb 17, 2007 05:57 PM
MUHerdFan
Technical Discussion
2
Feb 7, 2007 07:40 AM
joshn569
Modifications - Performance
19
Feb 1, 2007 02:51 PM
J.J.
General Discussion
8
Nov 6, 2006 03:55 PM




All times are GMT -7. The time now is 11:31 PM.


Top

© 2026 MH Sub I, LLC dba Internet Brands



When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.