New to Superhawks, some questions
Thread Starter
The Hypno-Toad
Superstock
Superstock
Joined: Jun 2006
Posts: 467
From: Milwaukee, WI
New to Superhawks, some questions
I bought a Superhawk last week, and of course one of the first things I found was this board. Fortunately there has been one of these for every bike I've owned. Unfortunatly I bought it used at a dealer so they couldn't tell me much about it. So I'm looking for any thoughts on the following performance issues.
The bike does not want to go at a steady speed below about 5k. It will accelerate through these rpm's, but not stay steady at them. This makes riding at less than 45mph difficult. I thought this being the relatively tourque heavy creature that it is this would not be an issue. It does have D&D exhaust on it, but I know nothing of the carbs. It runs well once it is up past about 50 mph. Also, it is only getting about 30 mpg. The dealership of course says that's just how these big V's are, but I know Honda better than that, with thier commitment to streetability. I will probably just have it dyno tuned, but was hoping for some insight. Obviously I can get some straighter answers here than at this dealer.
Any thoughts are greatly appreciated,
Kendrick
The bike does not want to go at a steady speed below about 5k. It will accelerate through these rpm's, but not stay steady at them. This makes riding at less than 45mph difficult. I thought this being the relatively tourque heavy creature that it is this would not be an issue. It does have D&D exhaust on it, but I know nothing of the carbs. It runs well once it is up past about 50 mph. Also, it is only getting about 30 mpg. The dealership of course says that's just how these big V's are, but I know Honda better than that, with thier commitment to streetability. I will probably just have it dyno tuned, but was hoping for some insight. Obviously I can get some straighter answers here than at this dealer.
Any thoughts are greatly appreciated,
Kendrick
Administrator
World Champion
Joined: Dec 2004
Posts: 105,287
From: Fulton, MO
As far as mileage goes, as your right hand twists the throttle, the mpg will plummet. I regularly get about 85-95 miles per tank at the track, but on the street I've gotten as high as 45 mpg on the highway (riding with some G-Wing riders @ 55-60). It's all inversely proportional. Use the torque of the twin. It will pay back dividends.
Now, for the surging, and that's what it is, you need to do some carb work. I'm guessing the PO did not install a jet kit, and if he did, didn't tune it properly. First thing to do is get the main jets sized right. Depending on where you live and other mods with your D&Ds, this could be anywhere from 175/178 F/R to 190/195 Keihin sizes. Once you get the mains right then you adjust needles at the lowest setting that will not cause the surging you currently are experiencing. That's what we call lean surging. Concurrently, adjust the mixture screws about 2 - 2.5 turns out.
If you don't want to install a jet kit, you can get by with shimming the needles up with small washers between 0.030" and 0.060".
I recommend Factory over Dynojet any day of the week, FWIW. Much easier to tune and no permanent modification of carb parts.
Now, for the surging, and that's what it is, you need to do some carb work. I'm guessing the PO did not install a jet kit, and if he did, didn't tune it properly. First thing to do is get the main jets sized right. Depending on where you live and other mods with your D&Ds, this could be anywhere from 175/178 F/R to 190/195 Keihin sizes. Once you get the mains right then you adjust needles at the lowest setting that will not cause the surging you currently are experiencing. That's what we call lean surging. Concurrently, adjust the mixture screws about 2 - 2.5 turns out.
If you don't want to install a jet kit, you can get by with shimming the needles up with small washers between 0.030" and 0.060".
I recommend Factory over Dynojet any day of the week, FWIW. Much easier to tune and no permanent modification of carb parts.
Senior Member
Back Marker
Back Marker
Joined: Jun 2004
Posts: 208
From: East Tennessee
K
For starters - what Greg said.
Are you a wrench turner? If so then put off having the dealer do anything for now. You should get into the carbs to see what you have anyway and since it's not running right now is a perfect time. See what jet sizes you have and the needle position, write it all down and report back here...
If you have no idea of the history then it's possible the bike was left sitting for a good while and you have gummed up carbs .... a good cleaning would solve some problems.
If you don't have your Haynes manual yet you can get a pdf version below (poor photos but better than nothing)
http://www.gofastvideo.com/gallery/i...ce-manual.html
'''Click on download video'''
For starters - what Greg said.
Are you a wrench turner? If so then put off having the dealer do anything for now. You should get into the carbs to see what you have anyway and since it's not running right now is a perfect time. See what jet sizes you have and the needle position, write it all down and report back here...
If you have no idea of the history then it's possible the bike was left sitting for a good while and you have gummed up carbs .... a good cleaning would solve some problems.
If you don't have your Haynes manual yet you can get a pdf version below (poor photos but better than nothing)
http://www.gofastvideo.com/gallery/i...ce-manual.html
'''Click on download video'''
Moderate-whore
MotoGP
Joined: Nov 2005
Posts: 9,052
From: Leander TX!!
Originally Posted by Hawkrider
As far as mileage goes, as your right hand twists the throttle, the mpg will plummet. I regularly get about 85-95 mpg at the track, but on the street I've gotten as high as 45 mpg on the highway (riding with some G-Wing riders @ 55-60). It's all inversely proportional. Use the torque of the twin. It will pay back dividends.
Now, for the surging, and that's what it is, you need to do some carb work. I'm guessing the PO did not install a jet kit, and if he did, didn't tune it properly. First thing to do is get the main jets sized right. Depending on where you live and other mods with your D&Ds, this could be anywhere from 175/178 F/R to 190/195 Keihin sizes. Once you get the mains right then you adjust needles at the lowest setting that will not cause the surging you currently are experiencing. That's what we call lean surging. Concurrently, adjust the mixture screws about 2 - 2.5 turns out.
If you don't want to install a jet kit, you can get by with shimming the needles up with small washers between 0.030" and 0.060".
I recommend Factory over Dynojet any day of the week, FWIW. Much easier to tune and no permanent modification of carb parts.
Now, for the surging, and that's what it is, you need to do some carb work. I'm guessing the PO did not install a jet kit, and if he did, didn't tune it properly. First thing to do is get the main jets sized right. Depending on where you live and other mods with your D&Ds, this could be anywhere from 175/178 F/R to 190/195 Keihin sizes. Once you get the mains right then you adjust needles at the lowest setting that will not cause the surging you currently are experiencing. That's what we call lean surging. Concurrently, adjust the mixture screws about 2 - 2.5 turns out.
If you don't want to install a jet kit, you can get by with shimming the needles up with small washers between 0.030" and 0.060".
I recommend Factory over Dynojet any day of the week, FWIW. Much easier to tune and no permanent modification of carb parts.
Moderate-whore
MotoGP
Joined: Nov 2005
Posts: 9,052
From: Leander TX!!
Originally Posted by Hawkrider
OOPS! I meant to say 85-95 miles per TANK. I will edit the post. Thanks for pointing that out.
Thread Starter
The Hypno-Toad
Superstock
Superstock
Joined: Jun 2006
Posts: 467
From: Milwaukee, WI
Thanks for all the advice. I'm kind of assuming that it was not jetted after the pipe was put on. Why someone would just put up with the odd low rpm performance instead of fixing it is beyond me though. I was going question that 85 mpg, but being the new guy I thought I would just let it sort itself out.
Thanks again (till next time),
Kendrick
Thanks again (till next time),
Kendrick
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