Member Contributer slowbird Posted June 2, 2016 Member Contributer Share Posted June 2, 2016 Long story short my 4th gen got killed in an accident and I replaced it with a 6th gen and haven't been happy with it. The riding position and handling, undertail exhaust...all very much better than the 4th gen. The ABS is a bonus. But this 6th gen has no low end and midrange compared to the 4th gen and I don't like the VTEC. ABOVE ALL ELSE the fueling is atrocious. It's snatchy and it doesn't feel very smooth. I was looking at getting rid of the 6th and getting a 5th gen however I hear the fueling isn't any better than the 6th. Is that true? I'm gonna go look at a 1999 tomorrow but it's yellow Link to comment Share on other sites More sharing options...
Member Contributer Duc2V4 Posted June 2, 2016 Member Contributer Share Posted June 2, 2016 Well if my 5 gen is an example I'd say it is better. I did 244 miles on one tank and got almost 53 mpg this past weekend. I have never gotten much better than 47 mpg on my 6 gen. However, my 6 gen does have a power commander, where as my 5 gen does not. Link to comment Share on other sites More sharing options...
Member Contributer Cogswell Posted June 2, 2016 Member Contributer Share Posted June 2, 2016 My experience is much like Duc's on 5th vs 6th - I have a PC on the 6th and do not have one (not needed) on the 5th gen. From the factory my impression is that the 5th gen ('99) is mapped better than the 6th gen. I probably would not be riding the 6th if not for the PC and a good injector cleaning. That done they seem to respond about the same. I have not ever though topped 45 mpg on the 6th gen - I'm usually in the low 40's and it can drop in the 30's when hammering on it through the mountains. Maybe it's the map I've chosen - don't know. If so for me it's a good trade off to get it running smoothly. I don't know if fuel mapping is different on '98/'99 vs '00/'01 - the latter have cats so maybe EPA was beginning to tighten down then toward being on the edge of too lean as we seem to be these days. Link to comment Share on other sites More sharing options...
Member Contributer slowbird Posted June 2, 2016 Author Member Contributer Share Posted June 2, 2016 Thanks for the quick replies. Just to be clear I'm not referring to fuel economy of even efficiency. Rather I'm wonder if the throttle on the 5th gen is smooth than that on the 6th. Does it have the same "snatchy" open/closed feeling when rolling on at times? Does it surge sometimes when cruising? All the different complaints about the 6th gen that owners I know said theirs didn't have but the one I bought does. Almost 10 years of riding VF/VFR's all carburated and I hop on this thing and the fueling feels like crap. Link to comment Share on other sites More sharing options...
Member Contributer Cogswell Posted June 2, 2016 Member Contributer Share Posted June 2, 2016 No issues what so ever on my '99 owned since new. When I bought it I came off a 4th gen and did not notice any difference in throttle response - never gave it a thought. I never heard of fueling issues until I got a 6th gen. As mentioned before, in 2000 5th gens got a cat, stainless headers and wax unit starter valves, so I don't know how they compare in smoothness to my '99. Maybe a Y2K or '01 owner can chime in. Link to comment Share on other sites More sharing options...
Member Contributer slowbird Posted June 2, 2016 Author Member Contributer Share Posted June 2, 2016 1 minute ago, Cogswell said: No issues what so ever on my '99 owned since new. When I bought it I came off a 4th gen and did not notice any difference in throttle response - never gave it a thought. I never heard of fueling issues until I got a 6th gen. As mentioned before, in 2000 5th gens got a cat, stainless headers and wax unit starter valves, so I don't know how they compare in smoothness to my '99. Maybe a Y2K or '01 owner can chime in. Oh! So you've gone from a 4th gen to a 5th and felt no difference? But you have felt the "fueling issues" in the 6th gens? Link to comment Share on other sites More sharing options...
Member Contributer Cogswell Posted June 2, 2016 Member Contributer Share Posted June 2, 2016 Exactly. The PC and bench cleaning the injectors took care of it on the 6th gen. Dirty injectors can cause fueling havoc as the ECU has no way of knowing if they are not delivering the calibrated amount of fuel. That only gave me about the last 10% - the PC accounted for the other 90. It's been a long time since I've ridden a 4th gen but I'd say that my 6th is now every bit as smooth. Link to comment Share on other sites More sharing options...
Member Contributer slowbird Posted June 2, 2016 Author Member Contributer Share Posted June 2, 2016 1 minute ago, Cogswell said: Exactly. The PC and bench cleaning the injectors took care of it on the 6th gen. Dirty injectors can cause fueling havoc as the ECU has no way of knowing if they are not delivering the calibrated amount of fuel. That only gave me about the last 10% - the PC accounted for the other 90. It's been a long time since I've ridden a 4th gen but I'd say that my 6th is now every bit as smooth. Thanks for that. I think I may try for another 4th gen or a 5th gen. I'm not too pleased with my 6th gen Link to comment Share on other sites More sharing options...
Member Contributer Terry Posted June 2, 2016 Member Contributer Share Posted June 2, 2016 My 99 5th gen has great fuelling, no surging, but the FI is definitely more sudden than carbs when getting back onto the throttle. Not bad, just different, maybe the difference between digital and analogue. I use my 5th gen for brisk and spirited rides on twisty roads and rarely get much more than 280 km before the low fuel light flashes, but they are very enjoyable km... Link to comment Share on other sites More sharing options...
hellindustries Posted June 2, 2016 Share Posted June 2, 2016 having ridden both: 5th gen all the way. Link to comment Share on other sites More sharing options...
Member Contributer Mohawk Posted June 2, 2016 Member Contributer Share Posted June 2, 2016 5th gen fuelling is not perfect (2000 model) a bit snatchy at low speed low opening. A power commander can iron all that out. Plus the 5th gen injectors being of a pintle design are practically self cleaning, if slightly less efficient ! Link to comment Share on other sites More sharing options...
Member Contributer paulmeisterpk Posted June 2, 2016 Member Contributer Share Posted June 2, 2016 My 6th gen was terribly snatchy until I synched the starter valves. That itself helped a ton. Before I did that, it was like an on/off switch with the throttle. I have a 5th gen ('98) and it may be slightly less snatchy, but the FI is still touchier on/off throttle than a carb bike. Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted June 2, 2016 Share Posted June 2, 2016 The sixth gen is a very clean bike. All sixth gen are California emissions approved. Cleaner emissions generally means leaner fuel mapping. The sixth gen, from the factory, is pretty much tuned to run on the ragged edge of what is an acceptable, but very lean fuel map, while running in the area that the EPA will be testing in (low to medium throttle positions and rpms. The mapping is actually pretty rich on the top end, for safety reasons). When an engine is tuned on the ragged edge of a safe lean tune, it doesn't take much to throw things out of sync and over the edge. Out of sync starter valves and dirty injectors can easy take what was once, lean, but safe and clean fueling and turn it in to fueling that is overly lean on a few cylinders. So when dealing with a stock sixth gen vfr800, your injectors and starter valves better be in tip top shape or else you will have issues. Now on the other hand, most sixth gen vfr800 owners choose to get away from the lean stock mapping. You will lose a few MPGs and gain some exhaust fumes in the process, but when the o2 sensors are deleted and custom fuel mapping is used, man these bike run great. ( I am talking a custom dyno tune and/or street tuning with a wide band by a competent tuner, not some map you down loaded off the internet). Speaking of o2 sensors, most of the VFR800s come equipped from the factory with narrow band o2 sensors. They are not wide band, so their usage is fairly limited. They are used by the factory ECU only during steady state, small throttle opening cruising. Basically when you are on the highway, the ECU takes information from the o2 sensors and leans the air fuel mixture to the edge off safe fueling. This edge of safe is constantly changing, even while your hand is steady, the air fuel ratio will be bouncing around from say 13-15:1 and this is what you feel as rough surging and a rough transition when opening/closing the throttle, as the ECU is going closed to open loop tuning (ECU saying, "okay I am looking at the o2 sensors and going lean. oh okay you're doing something with the throttle, I'll stop looking at the o2 sensors". All sixth gens and the 01-02 fifth gen VFR800 come with o2 sensors and if you want that smooth carbureted fueling feeling, you simply need to eliminate the o2 sensors and retune (though you will lose a few mpg')s. The o2 sensors can be eliminated really easily by disconnecting them and inserting 300 ohm resistors in their place to simulate the heater circuit (Power Commanders and Rapid Bikes come with o2 eliminators). This simply causes the ECU to think the o2 sensors haven't warmed up yet, so they are ignored and the bike just runs off the fuel map, also referred to as "Open Loop Fuel injection", similar to the 98/99 VFR800's that we all love so much. The mapping still wont be perfect, but it will at least stop going into and out of super lean closed loop mode. As far as tuning goes, you have a few options, mainly Power commander or Rapid Bike. Power Commander is a simpler more user friendly option, but it is fuel only and it's capabilities are limited. Rapid Bike Racing is fuel and ignition, plus has much much more potential than PC (Launch control/ traction control, full closed loop tuning in real time via 1/2/4 wide band o2 sensors etc....), but it requires a more competent user. With fuel plus ignition tuning, you can get back the lowend torque that the sixth gen is lacking from the factory. When the fueling is corrected, the ignition timing can be safely advanced much further that the factory overly lean mapping would ever allow. As much as 5 degrees of ignition timing advance can be added to the ignition map, in the sixth gen application, in the areas that have been richened up in the fuel mapping (from around 2500-7000 rpms) which results in a dramatic increase in low and midrange torque. The fifth gen VFR800's do not like as much added ignition advance, as the 4 valve "Tumble port" induction is more prone to detonation than the 2 valve "Swirl Port" induction on the vtec models, below 7000 rpms. The fifth gen VFR800 can only tolerate about another 2 degrees of timing, if I recall correctly. Link to comment Share on other sites More sharing options...
Member Contributer Africord Posted June 2, 2016 Member Contributer Share Posted June 2, 2016 My 6th gen seems to be fuel sensitive as well. I still have access to straight 87 unleaded (US), and my throttle response is much better than when I use E-10, or premium. I did balance my throttle bodies, and have a very smooth idle with 53k on the clock. I don't have a PC, and the only intake mod is a K&N filter. Exhaust is stock as well. Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted June 2, 2016 Share Posted June 2, 2016 That fuel sensitivity is more than likely a placebo. Link to comment Share on other sites More sharing options...
Member Contributer slowbird Posted June 2, 2016 Author Member Contributer Share Posted June 2, 2016 Thanks for all that info. I've read up quite a bit and understand the methods that would be required to smoothen this 6th gen out but I'm not sure I wanna dump money into it anymore. I just did the Snorkle and flapper mod and I feel like I've lost even more low end. What a waste of time. I just test rode a 5th gen. 1999 with 29,000kms on it. Rode very well. It has a similar powerband to the 4th gen I had. Lots of low and mid range. Effortless, smooth acceleration. The throttle felt very smooth too. Not snatchy at all. Too bad it was yellow. lol Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted June 2, 2016 Share Posted June 2, 2016 Pro Tip: 300 ohm resistors cost 99 cents for a pack of five. Flapper and snorkel mods don't really do anything, but add noise on an otherwise stock VFR. As far as lacking low end, that is very weird, I have never felt like my low end was lacking, though I can't really remember a time when my VFR was stock. Side Note: The 6th gen is an extremely rewarding bike to modify, partly because it leaves so much to be desired in stock form, while still not lacking in character which is only enhanced by modifying. Cliff Notes: If you don't like to tinker, the 6th gen may not be for you. Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted June 2, 2016 Share Posted June 2, 2016 17 hours ago, slowbird said: Thanks for the quick replies. Just to be clear I'm not referring to fuel economy of even efficiency. Rather I'm wonder if the throttle on the 5th gen is smooth than that on the 6th. Does it have the same "snatchy" open/closed feeling when rolling on at times? Does it surge sometimes when cruising? All the different complaints about the 6th gen that owners I know said theirs didn't have but the one I bought does. Almost 10 years of riding VF/VFR's all carburated and I hop on this thing and the fueling feels like crap. This is 100% what I described about the o2 sensors..... Link to comment Share on other sites More sharing options...
LookingHard Posted June 2, 2016 Share Posted June 2, 2016 slowbird, I'm not currently riding so take what I say with a grain of salt.......but would this help a bit? http://www.g2ergo.com/store/g2-street-tamer-throttle-tube/ LookingHard Link to comment Share on other sites More sharing options...
Member Contributer slowbird Posted June 3, 2016 Author Member Contributer Share Posted June 3, 2016 I think it's because I'm used to the 4th gen. I have seen the dyno graphs of both Gens stock and the 4th gen has alot more going for it in the low to mid range. I'm missing that. The 5th Gens seem to have it. ...and yes I do like to tinker. I'm not new here. I have had a 1986 VF500, a 1986 VFR750 and my 4th gen. I tinkered with them all. But I don't think I should spend time and money making a bike deliver its power smoothly when it should have from the factory. 6 hours ago, LookingHard said: slowbird, I'm not currently riding so take what I say with a grain of salt.......but would this help a bit? http://www.g2ergo.com/store/g2-street-tamer-throttle-tube/ LookingHard Ummm...nope. Wouldn't help. The 4th and 5th gens I test rode today were smooth. Then I hop on my bike and get irritated. 7 hours ago, CandyRedRC46 said: This is 100% what I described about the o2 sensors..... So if I added the O2 eliminators (which I have lying around here somewhere) the snatchy open/close throttle will go away? I figured it may help the surging when cruising but not the On/Off fueling when rolling on the throttle. Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted June 3, 2016 Share Posted June 3, 2016 Yes it will help. Link to comment Share on other sites More sharing options...
Member Contributer Lorne Posted June 3, 2016 Member Contributer Share Posted June 3, 2016 My '09 VTec suffers from the same snatchy throttle response that others have noted, and has since I bought it new 55,000 km ago. By contrast, my '99 VFR800 was almost as sweet as my '91 VFR750.This is most noticeable from zero to part throttle at lower (sub-5000) revs. The VTec operation isn't particularly bothersome. Neither have I noticed any significant difference in mileage or performance due to different gasoline. Mileage is pretty much the same, though the VTec ekes out a few more mpg. Range is a different story, as the slight mpg increase and a bigger fuel tank yield 10-15% greater maximum range. My feeling is that, power-wise, there is very little to choose from between the VFR800 and the VTec. The VTec also has more vibration in the handlebars than my earlier VFRs. Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted June 3, 2016 Share Posted June 3, 2016 This must be why everyone hates the VTEC model so much lol. No lowend or midrange and it doesn't pull away from the other vfr's until 9000 rpms. Man these 6th gens really are terrible when stock huh lol? It does have a slight bump up top due to the few extra degrees duration of vtec model's cams, which is nice. But you can really see how the EPA or Honda's own urge to eek out every last MPG on regular uneaded ruined the power band of an other wise great engine. Oh well, its all still there plus more, you just have to adjust the fuel/ignition maps, no big deal.... Link to comment Share on other sites More sharing options...
Member Contributer slowbird Posted June 3, 2016 Author Member Contributer Share Posted June 3, 2016 2 hours ago, CandyRedRC46 said: This must be why everyone hates the VTEC model so much lol. No lowend or midrange and it doesn't pull away from the other vfr's until 9000 rpms. Man these 6th gens really are terrible when stock huh lol? It does have a slight bump up top due to the few extra degrees duration of vtec model's cams, which is nice. But you can really see how the EPA or Honda's own urge to eek out every last MPG on regular uneaded ruined the power band of an other wise great engine. Oh well, its all still there plus more, you just have to adjust the fuel/ignition maps, no big deal.... Wow! That really tells it all right there. Well I picked up a nice 5th gen and am listing the 6th gen. A month of riding the 6th gen and I couldn't live with it. Sad to say it but riding it irritated me. This 5th gen is nice. Link to comment Share on other sites More sharing options...
Veefer800Canuck Posted June 4, 2016 Share Posted June 4, 2016 I put a throttle tamer tube on mine and it helped out, plus synched the throttle bodies and it works great from idle to redline. 1999, 100,000 km + Link to comment Share on other sites More sharing options...
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