High Speed Engine problem
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High Speed Engine problem
I seem to be having a problem with my Hawk cutting out at a fairly low top speed. It is at about 135MPH and a little over 8,000RPM. Now its only does it in 6th gear. All other gears go over 9,500RPM no problem. The speed I got is actual speed off of a aftermarket Speedo Computer. The bike speedo says 150-155. I was wondering if these bikes have some sort of speed govenor or if maybe I might have an actual problem? If so I'd love to hear suggestions on what I might do to solve this?
1988 SuperHawk
D&D Exhaust
K&N Air Filter
Factory Pro 4 degree Ignition advancer
Factory Pro Jet Kit (182F, 185R)
1988 SuperHawk
D&D Exhaust
K&N Air Filter
Factory Pro 4 degree Ignition advancer
Factory Pro Jet Kit (182F, 185R)
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Re: High Speed Engine problem
Now one other thing I did notice is that its not just stoping at that RPM but it falls back down every so often when doing that speed. Almost like its cutting out. It will climb to about 8,500RPM, but it will fall on its face for a second and slow down again (to about 8,000RPM), and then come back up, and so on......... Any more Ideas???????????????
1988 SuperHawk
D&D Exhaust
K&N Air Filter
Factory Pro 4 degree Ignition advancer
Factory Pro Jet Kit (182F, 185R)
1988 SuperHawk
D&D Exhaust
K&N Air Filter
Factory Pro 4 degree Ignition advancer
Factory Pro Jet Kit (182F, 185R)
Guest
Posts: n/a
Re: High Speed Engine problem
Our bikes probably won't pull 6th gear to redline. Of course, I wouldn't know as I have never tried. I do track days and still never get anywhere near top speed on my bike.
If you are saying that the bike pulls right up to 8500 rpm in 6th and then doesn't do much I'd say that that is all the bike has to give.
Unless you are doing this on a big, wide open track I'd say to slow the hell down.
Good day.
EDIT: and 1 post about this would have been enough.
If you are saying that the bike pulls right up to 8500 rpm in 6th and then doesn't do much I'd say that that is all the bike has to give.
Unless you are doing this on a big, wide open track I'd say to slow the hell down.
Good day.
EDIT: and 1 post about this would have been enough.
Guest
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Re: High Speed Engine problem
This is not a track bike it is a weekend road machine. The main reason for the 20 MPH difference is because of a different rear sprocket. I was told that it might be an ignition coil problem?? Does this theory hold any water or is this guy full of it??
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Back Marker
Joined: Jul 2004
Posts: 150
From: Los Angeles, California
Re: High Speed Engine problem
I doubt it is an coil problem. If it was, it would show up in the other gears at high RPM.
Simply put dude, you shouldn't be going that fast on the road. Your bike's trying to tell you something. Listen to it. It just may save your life.
Simply put dude, you shouldn't be going that fast on the road. Your bike's trying to tell you something. Listen to it. It just may save your life.
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Superstock
Joined: Jul 2004
Posts: 318
From: San Jose, CA
Re: High Speed Engine problem
Senior Member
SuperBike
Joined: Jul 2004
Posts: 1,015
Re: High Speed Engine problem
My 98 will pull red line in 6th gear. I did it multiple time on our track day.
I would suspect jetting to be the issue if it has had a jet kit installed. Could be too rich causing it to fall on it face in the upper rpm range.
I would suspect jetting to be the issue if it has had a jet kit installed. Could be too rich causing it to fall on it face in the upper rpm range.
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Back Marker
Joined: Nov 2004
Posts: 103
From: Atlanta
Re: High Speed Engine problem
Regarding going too darn fast on the street, when temtped to go stupid-fast, as a little reminder to oneself, one might take into account that, due to increased braking-distance and decreased traction/control, the risk-factor associated with going very fast increases logarithmically--not linearly--after one passes the 120 mph mark. (Just as it takes much more power to get that extra 1 dB of gain out of a high-end stereo, the risk-factor on a motorcycle increases at a much higher rate after one passes the almost-stupid speed of 120 mph).
In short, for every ten miles per hour one goes over 120 mph, one's chances of dying increase at a logarithmically higher rate, as the need for awareness of environmental factors (surroundings and road conditions) increases. (Remember, a track is a very highly controlled environment, and the open road is not.) And, as a point of reference, a rider might take into account that if he is in the habit of regularly going over 150 mph on the street, he--in all likelihhood--will eventually meet with mishap. And, this mishap--a patch of oil, a kitty or doggie crossing the road, or anything of that order--could likely leave both rider and motorcycle in a state that is "beyond economical repair", not mention the state in which it would leave the poor kitty or doggie.
cheers,
HotStreetVTR
In short, for every ten miles per hour one goes over 120 mph, one's chances of dying increase at a logarithmically higher rate, as the need for awareness of environmental factors (surroundings and road conditions) increases. (Remember, a track is a very highly controlled environment, and the open road is not.) And, as a point of reference, a rider might take into account that if he is in the habit of regularly going over 150 mph on the street, he--in all likelihhood--will eventually meet with mishap. And, this mishap--a patch of oil, a kitty or doggie crossing the road, or anything of that order--could likely leave both rider and motorcycle in a state that is "beyond economical repair", not mention the state in which it would leave the poor kitty or doggie.
cheers,
HotStreetVTR
Member
Squid
Joined: Aug 2004
Posts: 37
From: forest lake mn
Re: High Speed Engine problem
Why does everyone have to get so preachy? Is this a goldwing site? I thought the superhawk was a sportbike. My mistake. There's a time and a place for everything, I can pull redline in 6th on mine, I don't do it very much, but it's my choice. Half the time the front wheel is'nt on the ground until 110. I ride almost exclusivly on country roads, and I don't ever do freeway wheelies or that kindof crap, but if I feel like playing I have plenty of deserted roads I know of. I think riding in traffic at 70 on the freeway with all the idiots is way worse than a quick blast to redline! I have plenty of friends that pull wheelies whenever they want, whether there is traffic around or not and I chose to not ride with them anymore because of this. Sorry about the rant I just think we should help out when someone has a question, and not get all negative towards them.
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SuperSport
Joined: Dec 2004
Posts: 764
From: Nananimo, B.C.
Re: High Speed Engine problem
I agree with the previous post. Where I live there is a divided four lane brand new freeway that has enormously wide shoulders and VERY long straight stretches. It has very little traffic and runs through the country where no one lives.
The only reason I can think of that you might meet with some mishap would be tire failure or hitting some animal, which could also happen at a race track.
IMO its far more dangerous to ride in traffic than to do the odd high speed blurp when the right road conditions arise. I used to belong to the school of thought that anyone who exceeded 100mph on a two wheeled vehicle had a death wish. The last time I went out on my bike my speedo, at one moment, read 240 kmh (whatever that is in mph?). Now that I've done it, I think that its not as bad as I thought because you can accelerate and decelerate so fast that it hardly happened. :P
I had a suped-up '81 Mustang that I got up to 155mph on its speedo and I swear the body panels were about to tear off. Now THAT was dangerous.
The only reason I can think of that you might meet with some mishap would be tire failure or hitting some animal, which could also happen at a race track.
IMO its far more dangerous to ride in traffic than to do the odd high speed blurp when the right road conditions arise. I used to belong to the school of thought that anyone who exceeded 100mph on a two wheeled vehicle had a death wish. The last time I went out on my bike my speedo, at one moment, read 240 kmh (whatever that is in mph?). Now that I've done it, I think that its not as bad as I thought because you can accelerate and decelerate so fast that it hardly happened. :P
I had a suped-up '81 Mustang that I got up to 155mph on its speedo and I swear the body panels were about to tear off. Now THAT was dangerous.
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I've done 125 in a stroked '69 BeetleBug. Had fiberglass body panels, etc. I was TERRIFIED! The steering had pretty much quit working... Literally airborne. (Much younger and Way stupider.)
A quick pop to full speed with the right conditions is fine. BUT, it sounds like he's spending too long there up there, with all the data he's given.
Oh well, Darwin's always right there around the next bend...
I just don't like it when someone splats themselves, and all motorcyclists are judged from it.
phil
A quick pop to full speed with the right conditions is fine. BUT, it sounds like he's spending too long there up there, with all the data he's given.
Oh well, Darwin's always right there around the next bend...
I just don't like it when someone splats themselves, and all motorcyclists are judged from it.phil
Senior Member
Superstock
Joined: Apr 2005
Posts: 281
From: Denver, CO
Re: High Speed Engine problem
If you live for a while in North Dakota like I did, then you could feasably test your top-end speed as I did in my Ninja 250R (113 mph) and my Pontiac TransAm Firehawk (163 mph) where you can see 30 to 50 miles ahead of you on an open smooth country road with no wind and no trees or critters or even seeing other cars for hours.
I've found track-riding to be somewhat more difficult than a straightaway country road because of interesting curves, but I've never been to an oval yet.
Just my 2 cents but I'd not recommend top speed on a SHawk or over 135 mph on a regular basis. I've noticed dynamics change around there, and then again at about 150 mph. Maybe a once-in-a-lifetime kinda thing perhaps for bragging rights, if the conditions are superior such as ND or a good track.
I would suggest a lot of consideration before attempting or re-attempting 135+ on local roads and not done just on a whim! I hope you're fully geared-up!!!
Isn't top-speed on the SHawk something like 151 +/- a few? That's what several motorcycle magazines say. Does this author -need- to go that fast on a regular basis? Maybe he should re-evaluate the criticality of his choices! More power to 'ya anyway. Shrug. Good luck dodging deer!
Would it be at all possible if you could put me in your will?
I've found track-riding to be somewhat more difficult than a straightaway country road because of interesting curves, but I've never been to an oval yet.
Just my 2 cents but I'd not recommend top speed on a SHawk or over 135 mph on a regular basis. I've noticed dynamics change around there, and then again at about 150 mph. Maybe a once-in-a-lifetime kinda thing perhaps for bragging rights, if the conditions are superior such as ND or a good track.
I would suggest a lot of consideration before attempting or re-attempting 135+ on local roads and not done just on a whim! I hope you're fully geared-up!!!
Isn't top-speed on the SHawk something like 151 +/- a few? That's what several motorcycle magazines say. Does this author -need- to go that fast on a regular basis? Maybe he should re-evaluate the criticality of his choices! More power to 'ya anyway. Shrug. Good luck dodging deer!
Would it be at all possible if you could put me in your will?
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Squid
Joined: Mar 2005
Posts: 62
Re: High Speed Engine problem
A common mod is to drop a tooth on the front sprocket.
Apparently this will let you hit redline in top without scarificing top end speed... the lower gearing helps make better use of the engines torque.
In standard form I dont believe you can hit redline... but with some pipes and better breathing the bike should pull easy 155mph
I did a quick run up to 220kph (137.5mph) last night on the way home and there was easy more than 30kph left in it !!
Will give it another whack next time i get the chance and see if i can hit the limiter and how long it will stay there to see if i have any problems.
Regs,
Beefa
Apparently this will let you hit redline in top without scarificing top end speed... the lower gearing helps make better use of the engines torque.
In standard form I dont believe you can hit redline... but with some pipes and better breathing the bike should pull easy 155mph
I did a quick run up to 220kph (137.5mph) last night on the way home and there was easy more than 30kph left in it !!
Will give it another whack next time i get the chance and see if i can hit the limiter and how long it will stay there to see if i have any problems.
Regs,
Beefa
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Joined: Aug 2004
Posts: 203
From: Belgium
Re: High Speed Engine problem
I can confirm that I saw genuine 244 km/h on my GPS screen when I tried for top speed. 97 Hawk, with no mods to engine except race exhaust Arrow. It was not trackday, but on highway with 250 km/h speed limit and it was empty, but I was way too busy looking at GPS screen to check if I had hit redline. Would it have had pulled further? Don't know, saw cars in front and got too scared and slowed down.
155 mph on speedo on Hawk sounds almost right, if you take correction (speedo on motorcycle only good to indicate beer prices - it lies constantly.
But: about 100 bhp on bike and top speed over 155 unreachable - can't agree, sorry. Saw genuine 261 km/h on CBR600 on GPS screen. No, it was not new CBR, it was not even RR, it was older, carburated (f4 I think) real 100 bhp CBR (we talking rear wheel figures, aren't we?).
Hawk should have around 103 bhp at rear wheel with sorted exhaust and weight I guess is around 185 kg dry (that' what I have achieved with my bike by "fat cutting"), so I think it is weight that makes difference.
155 mph on speedo on Hawk sounds almost right, if you take correction (speedo on motorcycle only good to indicate beer prices
- it lies constantly.But: about 100 bhp on bike and top speed over 155 unreachable - can't agree, sorry. Saw genuine 261 km/h on CBR600 on GPS screen. No, it was not new CBR, it was not even RR, it was older, carburated (f4 I think) real 100 bhp CBR (we talking rear wheel figures, aren't we?).
Hawk should have around 103 bhp at rear wheel with sorted exhaust and weight I guess is around 185 kg dry (that' what I have achieved with my bike by "fat cutting"), so I think it is weight that makes difference.
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SuperSport
Joined: Dec 2004
Posts: 764
From: Nananimo, B.C.
Re: High Speed Engine problem
When my speedo read 240kmph it was still accelerating well enough that I have no idea what the top speed could be. That said, once was enough and I have no idea to explore up there again. A -1 front sprocket is in my bikes near future. 120-125mph is about as fast as I plan on ever going again.
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SuperSport
Joined: Mar 2005
Posts: 758
From: Laurel, MD
244kph is 151.6 mph. Top speed on the vtr is about a real 157 = about an optimistic 170 on the speedo.
261 kph is 161 mph. Possible, but not likely. And weight is not a factor at all. Weight affects acceleration, drag affects top speed. Sounds wacky but its true.
Here's an interesting table:
DRAG FORCE ON A ONE-SQUARE FOOT SQUARE PLATE
Speed Drag Force Horsepower Required to Overcome the Aerodynamic Drag
0 mph 0 pounds 0 hp
100 mph 33 pounds 9 hp
200 mph 133 pounds 71 hp
300 mph 299 pounds 239 hp
261 kph is 161 mph. Possible, but not likely. And weight is not a factor at all. Weight affects acceleration, drag affects top speed. Sounds wacky but its true.
Here's an interesting table:
DRAG FORCE ON A ONE-SQUARE FOOT SQUARE PLATE
Speed Drag Force Horsepower Required to Overcome the Aerodynamic Drag
0 mph 0 pounds 0 hp
100 mph 33 pounds 9 hp
200 mph 133 pounds 71 hp
300 mph 299 pounds 239 hp
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Posts: 203
From: Belgium
244kph is 151.6 mph. Top speed on the vtr is about a real 157 = about an optimistic 170 on the speedo.
261 kph is 161 mph. Possible, but not likely. And weight is not a factor at all. Weight affects acceleration, drag affects top speed. Sounds wacky but its true.
261 kph is 161 mph. Possible, but not likely. And weight is not a factor at all. Weight affects acceleration, drag affects top speed. Sounds wacky but its true.
Not sure if there is any difference with US version, as I got European version of Hawk, but I honestly beleive that Hawk can do 245 km/h flat out, so if you say it can do 157 mph - well, I am pleased to hear it - that's nice
About 161 mph on CBR - it is absolutely genuine figure - I was riding it when I saw it
I know and fully agree about effects of drag, and actually quite few factors (including weight) contribute to top speed, but yes - drag takes most of it. But again - it just confirms case with CBR - it is way smaller if you take frontal cross-section comparing to Hawk, fully faired and aerodynamically way better developed than Hawk.
Basically I'd try to recall some of my education in university..
never thought I'd need it...
So, yes - you are correct, but equation contains more than just speed and size.
For calculation of force we should use "equivalent area" principle, so drag calculated as required force to move through air "equivalent" flat plate. It is calculated as real area of section * by drag coefficient. So, on drag coefficient - CBR certainly miles ahad of Storm, but on cross-section size probably same. But if not for that coefficient - Hayabusa would reach probably only 150 flat out
Hmm...makes you think, doesn't - may be some aftermarket plastc bits are not so useless :wink:
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Re: High Speed Engine problem
it may be just the us bikes that go slow, my 97 storm has been dyno jetted with KnN air box mod and micron cans and set up on the dyno qand is running 115.3bhp at the wheel and will hit a true 165mph according to the dyno print out.sorry the pic is a bit big. :wink:
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Posts: 203
From: Belgium
Re: High Speed Engine problem
wow, that's awesome! I think it is highest figures I saw so far without more serious mods.
What did they do to aribox except K&N filter?
And - did they install Dynojet Stage 1 or Stage 2 or...?
I mean - was there any mods performed on carbs (drilling etc.)?
What did they do to aribox except K&N filter?
And - did they install Dynojet Stage 1 or Stage 2 or...?
I mean - was there any mods performed on carbs (drilling etc.)?
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SuperSport
Joined: Mar 2005
Posts: 758
From: Laurel, MD
I was thinking this was a pretty good example of what I've been saying until I realized that dyno "speed" is without any drag. And drag is the primary limiting factor in speed.
From the chart, it looks like that speed was reached in 5th. Is that right? It looks like it may have hit the rev limiter.
From the chart, it looks like that speed was reached in 5th. Is that right? It looks like it may have hit the rev limiter.
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Re: High Speed Engine problem
i will post a pic of the air box mod as it is to long winded to explain,not sure of what gear it was in i was not there when it was done.
the man that did it for me builds race bike in his spare time.
as for the speed i have had it reading 175mph on the clocks and thats on standard gearing.
the man that did it for me builds race bike in his spare time.
as for the speed i have had it reading 175mph on the clocks and thats on standard gearing.
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Joined: Mar 2005
Posts: 200
From: Ottawa
Re: High Speed Engine problem
I have never gotten close to redline in 6th, but I regualrily hit 200kms(124mph), and have gotten to 160mph on my GSXR.
now the guy asked a question about his bike, not about how he should ride it.
I would not suspect coils, as was stated before, it would happen in every gear. I would look more into fuel/air delivery. Has the airbox been modified at all? A pressure change could cause this at high speeds.
Remember stock is BAD!
SuperSport
SuperSport
Joined: Jun 2004
Posts: 760
From: Jacksonville FL
Re: High Speed Engine problem
Looking at the dyno graph I just have one thing to say.
Who was riding the bike on the dyno and shifting using the clutch?????!!!!!!! Those are really slow shifts.
That being said I can attest to a 135mph on a bone stock shawk in 6th gear (drag limited top speed). I never did keep in it 5th and see if she would pull more.
I use to have to take the expressway at 545 in the morning and I was many days that I would just open her up in 6th. With a backpack on she would hit a drag limited 130mph.
Who was riding the bike on the dyno and shifting using the clutch?????!!!!!!! Those are really slow shifts.
That being said I can attest to a 135mph on a bone stock shawk in 6th gear (drag limited top speed). I never did keep in it 5th and see if she would pull more.
I use to have to take the expressway at 545 in the morning and I was many days that I would just open her up in 6th. With a backpack on she would hit a drag limited 130mph.
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Superstock
Joined: Apr 2005
Posts: 281
From: Denver, CO
Re: High Speed Engine problem
Having being in the USAF since 1993 and 5 of those years working at 2SOPS (aka GPS) I can attest accuracy for civilian use is only +/- 10 percent unless you have a crypto-key and a military GPS receiver (the key is only good for one day) during wartime. Currently I believe "selective availability" is set to "ON" at each satellite for our current operations in the Middle East and elsewhere. Under peacetime, it's set to "OFF" at each bird so that civilians can get +/- 1% accuracy like the military. We set it to "ON" so that the enemy can't go and buy a GARMIN and use our own technology as an assist against us. A lot of people use it for speed verification, especially in top-speed car runs (and I guess motorcycle runs too). I would suggest a G-Force or an accelerameter by Bel Electronics that uses a nice simple doppler K-band ping. These cost about $200 and can measure your Hp and other things like lateral "g"s.
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Superstock
Superstock
Joined: Jun 2005
Posts: 489
From: San Antonio, TX
i will post a pic of the air box mod as it is to long winded to explain,not sure of what gear it was in i was not there when it was done.
the man that did it for me builds race bike in his spare time.
as for the speed i have had it reading 175mph on the clocks and thats on standard gearing.
the man that did it for me builds race bike in his spare time.
as for the speed i have had it reading 175mph on the clocks and thats on standard gearing.
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