Surging and dead spots

Hi there, I purchased my first VFR in april of 2010. I was deployed and was looking at this thing in all the magazines and absolutely fell in love with it. I know of the lineage of the VFR and am a devout Honda fan. I have an 03 RC51 an 08CBR1000RR and this bike. Even though this is the most ridden of all my bikes 13k miles thus far. I kinda have a love hate relationship with this bike. I learned of the crap mapping of gears one and two and have a Z-Bomb on order. My main issue now is a surging im experiencing while riding. Its not wild but its there nonetheless. I ride a four mile stretch to work and the speed limit is 50mph. I run this in fourth gear around 4200 rpm at about 55mph. Its here that i notice the bike will just cut throttle slightly but will respond with more input and the opposite holds true some times it will speed up abruptly not wildly but enough i can tell. I dont notice this in any other gears really. Another issue is When i lived on the east coast of North Carolina i would occasionally ride out to the mountains. I noticed while climbing up i would start to get massive dead spots in the throttle. I would then kill the bike turn it on but not start open throttle and close it then shut off and restart the bike and it would run fine after. At no time has the FI light illuminated. The bike has done this every time I ride it up to and down from a large elevation change. Just kind of wondering if any one has had this or these experiences. My bike is bone stock save for the seat bars and wind screen. Thanks for any input guys.

 

Power Commander might fix it or maybe a bad sensor or computer ???

 

First question - is it a VFR 800i?

Second question - if it is, 4200 RPM in 4th gear is not the sweet-spot of the bike. Rev it up!

Third - if it is, a Power Commander and a custom map will make a world of difference. Try it! It's a relatively inexpensive mod. Take it to a tuner who has experience with the bike.


My 2004 VFR 800i drove me to distraction with the snatchy throttle response at low RPM - especially in 1st. A PC and an expert Dynotune made it a wholly different machine. Try it!























.

 

Its a 1200. Sweet spot or not the bike shouldnt be surging, period. But here is my issue. Totally stock bike purchased brand new, Why should i be dumping more money in something that i believe they are charging way too much for just to make it run right. I got a reasonable deal on it at the time but This is a Honda were talking about here. A few personal comfort mods, change the oil and put gas in it is all i should have to worry about. Granted scheduled maintenance of course. If it were an Accord i wouldnt have to do crap to it, and it would run 200k or more without issue. Like I say I have a real love hate for this bike. Its a very frustrating thing.

 

I do not know anything about the 1200. I hope it works out. My experience is that almost every EFI motorcycle benefits from a Power Commander and a map. Of all the modifications I made on my VFR 800i, that was the biggest bang for the buck. Again, I don't know squat about the 7th Gen 1200, so I will back out now. Good luck, amigo!

 

No harm there Alaskan. But dont you agree that a 13k dollar bike especially a Honda should run without flaw from the factory.. Now if I had a pipe on it i would expect some hiccups and what not. My 08cbr with stock map was as smooth as silk. Im just not totally on board with Hondas fly by wire yet. Z-Bomb is on the way, we'll see how that does.

 

Emissions are tough on these bikes, I would try a power commander. Mine was a mess withoot it.

 

The secondary muffler valve might be your problem at 4200rpm if its bone stock. Might wanna try leaving that open by removing the solenoid cable. A pcV and muffler is a better solution.

 

I'm afraid the Z-Bomb will do nothing for the poor fueling at small throttle openings and lower rpm's, the Z-Bomb is a work-around the 1st-2nd hp/torque hole. A PC-V or Juice Box pro will help the fueling greatly. There is a new map from Honda for the stock 2010/2011 VFR's but I'm not sure if it's available in the US.

The problem lies with the local pollution laws rather than Honda, Kawasaki, Yamaha etc..., the manufacturers have to meet ridiculous limits and the only way to do it is to lean the fueling off so low it causes inherent problems such as surging and poor throttle control etc...Bikes such as the VFR 1200 have to meet emission limits the same as 1000RR's and it's very difficult to do. Larger capacity engines require more fuel, however, this produces more emissions, catch 22..!

Cheers,
Smithy.

 

Good intel there Knobby. I did get my Z-Bomb today and it has smoothed it out a good bit but not a complete fix. One strange thing I noticed immediately was the valve on the muffler opening at 4K in first and second gear. I thought this only occurred at 6K and above. Unless it has been opening at 4K in third and higher gears but by then there is just too much wind noise to hear it. Is this what all other Z-Bomb users are seeing with stock exhaust systems? I completely see and understand how difficult it is to meet emission requirements but im still bitter over the thought of spending more money just to make this bike run smooth the way i know it could and should from the factory.

 

Please don't be misled into thinking the Z-Bomb does any more than disable the software induced 1st & 2nd gear throttle restriction below ~5000rpm. It has no effect on the fueling and no effect on the opening rpm of the muffler valve, which opens between 4000 and 6000rpm depending on throttle position, rpm and load. It's easy to have the muffler valve open permanently, simply disconnect the cable from the stepper motor which lives behind the right side seat fairing, the valve is designed to be spring loaded in the open position so when the cable is disconnected it will naturally stay open.

Trust me, if Honda could easily make the engine run smoothly at low throttle openings and low rpms, they would indeed do it. I look at it like this....as an example the 1000RR, might use x amount of fuel to run at 3000rpm at a certain throttle opening and load, the VFR1200 has to be able to do the same thing with the same amount of fuel and ~100kg more weight....also with 20% more engine capacity, in my mind it is very difficult to do..! As another example, and depending on the country, the emmissions laws can be the same for motorcycle engines of 750cc up to 1500cc and each of them have to use the same amount of fuel to do the same thing, very frustrating for the manufacturers I would imagine.

I have a DCT and the Z-Bomb is no use to me and as such the 1st & 2nd gear issue is still there... but I have fitted a JuiceBox Pro with a custom map which has immediately cured the low end fueling problem I had which was caused by the lean fuel condition.

Cheers,
Smithy.

 

I have the same problem exactly i have been told I'm running at too low an rpm. I'm in second gear and rolling on the throttle from 4 to 4200. At 4200 it feels like there is a rubber band holding me back. Just came back from doing 1200 km ride through hills of Pennsylvania. Lots of twisties. It is an intermittent problem. Any help would be great.

 

Alexdig, in the twisties nothing good happens below 5000 RPM.

 

i would definately have service manager ride this bike go to all nearby dealers if possible...that doesn't sound right...engine should hold a steady speed....the first and second gear flat spot is easily cured with a z-bomb, but my bike fuels perfectly aside from that( and the EPA lean ness) for that you need a PC V or Bazzaz Z-FI ,i think you have a warranty issue, hope it hasn't expired

 

just to verify...surging while holding a steady speed or while accelarating ?????

 

I have done the 1st and 2nd gear fix; PC V with 2 bros map, Leo Vince slip-on, BMC air filter.
Absolutely no surging, fueling is excellent now.