So Ive owned my Superhawk for a couple months now. racked up about 4k on it so far this summer. Absolutely love the bike. When i got the bike from the previous owner it had alot of little issues needed addressed. Nothing too drastic.... just basical tlc and some jerry rigged stuff. Anyways Ive been reading up on this site and gained a wealth of knowledge here. So far I have depaired, removed the Ca. smog stuff. Built the low buck carb tool. rejetted carbs. Plugged some vac leaks. Installed new plugs. Changed fluids. New tires. Installed new rectifier and manual CCTs.Adjusted the suspension. Adjusted the TPS
Right now the bike is running pretty good. Starts right up. Idles fine. No flat spots. I get at least 100 miles before the fuel light comes on.
The one thing Id like to mess with is seeing if I can make the bike cruise better. The bike seems to want to hunt a bit or lurch a bit when cruising. The engine seems to like to be around 4500 when on the highway/freeway. But even at there its not super smooth.
I know that its somewhat the nature of the Superhawk but I am wondering if maybe my jetting might be off or perhaps since I havent really messed with the mixture screws that that might be where to start.
Right now I believe I am at 2 or 2 1/2 turns out.
What are you looking for when adjusting the screws?

 

There is a "saddle bag" in the middle of the horsepower/r.p.m. power curve of the Generation I VTR1000F (1997-2000). The issue is resolved with the 2001 model, where they tweaked the power curve and added a few other really nice amenities (digital fuel gauge, digital clock, dual trip meters, digital temperature gauge, digital speedometer, and larger fuel tank).

The saddle bag in the Generation I VTR is actually generated by the ECU (Electronic Control Unit), located under the seat, in a rubber boot that mounts beneath the seat latch mechanism. The ECU-generated saddle bag occurs right between roughly 3200 and 4800 r.p.m. My understanding (as per D&D Exhaust R&D engineers) is that the story behind this dip in power is that, so that the bike could initially pass EPA standards with better numbers, the ECU puts a saddle bag in the power curve right in the 3200-4800 rpm range. This is a pain in the ****, since that is the range where you generally find yourself hovering while on the highway (between 50-60 mph, especially). I think that they do the EPA qualification test at 55 mph, or at least I believe that is where they qualified bikes in 1997, when the VTR1000F was EPA-qualified.

Since the saddle bag is programmed by the computer itself, you can't get rid of it by adding expensive mods like custom cams or ported heads (SuperChicken II had ~120 r.w.h.p., with all kinds of elaborate power mods, and, since it had a 1998 ECU, SuperChicken II still had the saddle bag in the same dang spot--it was just 15 h.p. less obvious). lol

Even so, there is a very affordable and worthwhile mod that will really compensate for the saddle bag through the cruising range, and it is one of the more popular modifications discussed on this Forum: Adding a 520 chain-and-sprocket conversion kit, going one tooth down on the front sprocket and two-or-three teeth up on the back sprocket. Also, adding the light-weight, aluminum rear sprocket and the lighter chain of the 520 conversion kit will get rid of a good chunk non-reciprocating mass (dead weight) in the drive-train, and it will thus give you a noticeably nicer throttle response from 0 mph on up to the rev-limiter max. (Vortex 520 Sprocket and Chain Conversion Kits are just great, and they come in all kinds of splashy colors.)

You should note, however, that by adding an aluminum rear sprocket, you are also inviting yearly maintenance on the rear sprocket, as they usually only last about 10k-12k-miles--if that--on the "torque-monster" VTR. Even so, if you have a motorcycle stand, it's a cinch to change the rear sprocket; you just need to remember to have some anti-seize penetrating lubricant on-hand, to etch free the oxidation that builds up on the sprocket mounting bolts. (PB "Blaster" Penetrating Lubricant and a "breaker bar" work unbelievably well.)

I might be mistaken, but I think that it might also be possible to drop a 2001-2005 ECU in any VTR1000F, but they are kind of pricey, unless you can find one on eBay. (I would make sure before buying one, as some of the "old guard" on this Forum almost certainly know whether or not the newer ECU will work with pre-2001 VTR's.)

There is also a "de-restrict" ECU re-manufactured in China, but I know next-to-nothing about these modified ECU's, so I can't comment on them, one way or the other.

All told, it seems to me that the 520 conversion kit is the most affordable mod to deal with the saddle bag, and it would still benefit overall performance, even if you eventually bought another ECU to get rid of the saddle bag entirely.

On SuperChicken III (with stock engine, D&D exhaust, and Factory Pro jet kit), I have the one-down (in the front), three-up (in the back) 520 conversion, using a hybrid (Supersprox) rear sprocket. The Supersprox rear sprockets are slightly heavier, so not quite as much fun, but they last roughly five times longer than all-aluminum sprockets. (I used to have a two-up--43-tooth--rear sprocket, but with Supersprox that item was out of stock, so I went with the three-up [44-tooth] rear sprocket. Just by adding one tooth to the rear sprocket in relation to the previous 43-tooth setup, I noticed a very nice change for the better in the saddle bag dip.) You might want to note also that by adding a 43- or 44-tooth rear sprocket, you lose a little speed off of the top-end, as the rev-limiter kicks-in earlier, but I never go over 140 mph, anyway.)

cheers,
--Professor Chaos

 

What the hell are you talking about? Saddle bag in the power curve....really???
Here is a pretty much standard VTR dyno chart..... if there was some kind of "saddle bag " or whatever how come there is no dip in the power curve??



And your gearing recommendations have been covered on this forum quite thoroughly. While some my like it all you really do is make 1st gear unusable and turn you 6th into the same ratios as a stock geared bike in 5th....

Also Vortex make the worst Al rear sprockets on the market..... well unless you like sprockets that wear out in 4k miles.....

 

Now for your questions.... how is the bike jetted right now?
Also the only real way to set the pilot screws is with an idle drop setting. You will need the proper tool to do the adjustment and it is covered in the service manual.

 

Mine does very well running around 3800-4200 at 70+ mph on the highway. I don't get lurching or any feeling of being flat. I think I'd be suspicious of how clean the carbs are, but I'd also like to learn more about the upgraded ECU. I don't know if I want to do anything to lower my mpg results though.

As for mileage, I've found if I'm running longer distances, not stop and go stuff, and be gentle with the throttle I can get 125 or so to the low fuel light coming on. I relate it to driving 4 barrel carbs on older cars. if you want to play with the power, you pay at the pump.

 

I don't know about your bike, but my 2000 has no power loss from 3200 to 4000, in fact at around that RPM is where I can power wheelie in 1st or 2nd gear.. no clutch. (just crack the throttle and pull up on the bars when not leaning forward, and up she comes)

I do have a 43 tooth rear sprocket, but any more than that makes 1st gear useless, at least in my experience. (I have a 15T front sprocket going unused)

 

With the carb work noted in my signature, and pilot screws 2 1/2 out, I have no surging or flat spots at any speed. That holds true from sea level up to 6,000 feet elevation. I do get the very occasional carb fart from time to time at sea level though. I put up with that to have it running perfectly anywhere above 1,000 feet.

Once you have it dialed in for where you ride, keeping those puppies clean is most important.

And like 8541Hawk said, others can help you better if you post exactly what you've done to your carbs. Also you would benefit from keeping a stock air filter in the airbox, and don't modify the air box.

 

You don't see the drop in torque and the corrisponding lag in HP increase around 4.5 to 5.5 RPM? I do. However, it's so small, I doubt it would even be felt/noticed.

 

I've been looking at HP/Torque curves for only 20 years or so, so maybe I'm a little green, but I've never heard of a "saddlebag" mentioned. A dip or flat spot? Actually, in my opinion, the SH has one of the very best torque curves I've ever ridden. Properly tuned, there is no dip to speak of. And I hate seeing gearing advice to solve possible tuning issues. It's pretty easy to have a plugged jet, wrong float height, gummy carb, gasket leak, vacuum hose problem, etc., on a 12 year old bike, regearing or slapping a new ECU on it would be a waste. Problem will just move to some other rpm. And I have had bikes with this issue, '95 carbed Ducati 900ss is one.

 

Back to the OP: I would say, clean the carbs, then get them synched, that will probably take care of it. If you want to be ambitious find 8541Hawk's carb tuning thread that gets into detail on setup.

 

Ummm did you read the post I was replying to? It was stated that the dip was in the 3200 -4800 rpm range and was referred to as a built in cut in power in the ECU for some type of emissions control.

As for the very small dip or leveling in the chart posted, well it's not my bike or chart so I really can't comment on it except to say that I agree that you would not be able to feel it.

 

I set up my carbs as described in one of the carb set up threads... 48 jets. 175 front and 178 rear with shimmed stock needles. Off the top of my head it was like .040 or something. Carbs are clean... clean. New air filter and subfilters. The front carb slide had three holes in it so I fixed that. I also did the TPS. I slotted the mixture screws so I can adjust. Just not sure about the idle drop method. I guess I have to do some digging to do.
Bike is synched too.
Like I said it runs pretty good. I dont have anything to measure against it other than other members word here. The bike doesnt have a flat spot. It runs fine throughout the throttle range. It just feels like the bike it dragging. Brakes and chain arent dragging by the way.
By the way, on a side note, I just ordered a 520 kit. Went with the 16/43 setup but with a superlite steel sprocket.

I used to tune my carb on my jeep with a vac gauge. Wondering if I can do the same with the bike? Its been awhile since I did the jeep.

Lastly as a note. Right now with the stock sprockets and the way it stands, the bike will not do a power wheelie. Or I should say that the front hasnt came up on me and I have pretty much pinned it numerous times from start up to maybe 120 or so. The bike hauls though... just doesnt pick up the front end. ( Im 6'3" and 220lbs though if that matters)

Anyways looks like I should find the mixture thread and try that.

 

The slight dip in the power curve that I see (with D&D slip-ons and a Factory Pro jet kit on a 1998 VTR) is actually not located between 3200-4500 rpm, as I state in my first response to this thread, but the slight dip actually resides in a narrower range of ~3500 to 3750 rpm at stock gearing (520 conversion, 15-/44-tooth sprockets), in fifth gear. It seems to be most pronounced at around 3700-3750, and there is no issue at all at 4000 rpm and above. As msethhunter notes, it's not that big of a deal, because it is a very slight dip in power, but it is there. (It might be something specific to using the D&D slip-ons, as D&D's are not very restrictive, i.e., are very loud cans. If so, it might be a moot point, since D&D no longer lists the VTR1000F in its drop-down menu of Hondas for which they offer slip-on exhaust.)

When the bike was being jetted, we called D&D Exhaust Tech Support, and the person with whom we spoke mentioned specifically that their experience with helping people jet the VTR with their slip-on exhaust was that this little dip in power only occurs on Generation 1 VTR's using their slip-ons--and, again, it's not that much of a dip. He mentioned also that Honda changed the ECU slightly with the advent of the 2001 model year. He was apparently right about the ECU being tweaked for the Generation 2 VTR, because in the "Model History" section of the Motorcycle News "Review" Page for the VTR1000F , they mention "tweaks" to the "carb/ignition settings" as one of the enhancements of the 2001 model year. It would be interesting to find out what exactly Motorcycle News means by "tweaks" and how this might relate to the "de-restrict" VTR1000F ECU's that are for sale on eBay.
_________________

Regarding Vortex rear sprockets, you're right that the "standard" Vortex aluminum sprockets suck--very much so. (I never got more than 6000 miles out of one, even if I toned-down my 0-60 mph behavior.) However, the new version of the Vortex aluminum sprocket not only comes in anodized finishes, it also features what they call the "PTFE Hard-Coat" alternative: It is coated in Teflon, to reduce friction and wear and thus extend life. I got 14 months' worth of wear out of one (probably 10k-11k miles, since the VTR is my primary means of transportation). The "standard" Vortex aluminum sprocket might make a nice martial arts weapon because it is light, balanced, and has lots of pointy edges, but it is not really good for much else.
_________

cheers,
--Professor Chaos

 

And I typically ride around at 3722-3724 rpm, now that explains it!

 

Well the change in 2001 is that they put a bit more advance into the ECU. They did this to compensate for the smaller cams they started using that year.

Now for the dip you are seeing. It happens right when the carbs are transitioning from the pilot circuit and onto the mains.

From my research this is caused by the front slide opening too soon. Now Moriwaki & HRC came up with a way to deal with this issue and I explained it all in the carb set up thread.

The issue could also be caused by the needle profile. As I have never used a Factory Pro kit, I can't really comment on that.

Changing the gearing does nothing but mask the issue and is a band aid fix at the best and has many draw back associated with running it.

So IMHO what you are seeing is a carb issue not an ECU issue.

Now for these ECU's that you have been talking about, could you post a link? The only replacement ECU that I have ever seen is the HRC unit and it is only for the '97- '00 bikes.

As for the carbs, I have not seen any difference between the model years. I've done a fair share of carb work on these bikes and if someone can show me what is changed, I would be happy to hear it.

So in closing, IMHO what you are seeing is a carb issue not an ECU problem.

Oh and as a little example of how accurate MCN really is how about this tid bit from the article you linked to:

" Honda VTR1000F Firestorm's engine is well tried and tested in a number of 1000cc Honda v-twins (most recently the SP-2)"

So if they can't figure out that a SuperHawk and a RC51 have completely different engines then how can they be believed on anything else they might say??

 

I did, thats why I stated the RPM range where it shows man. Chill. Don't be so defensive.......

If you read my post, I was agreeing with you in a round about sort of way. Remember reading this line?

"However, it's so small, I doubt it would even be felt/noticed."

 

I'm 6' 270lbs and mine will bring it up in first with the same 175F 178R 48 Pilots, no shims, stock sprockets. Keep trying, you'll get there.