Member Contributer Stumpthumper Posted July 18, 2008 Member Contributer Share Posted July 18, 2008 I have a 6th generation that I picked up used with 6000 miles on it. It had the recall done and it runs strong otherwise, however.... Every now and then between 3-5K rpm the bike will stumbles. I've seen this stumble on the forum, but these seem to be more than stumbles. It's like the bike loses all power for what seems like a full second or two and then kicks back in, jerking forward. I don't understand why people complain about the Vtec, but this stumble is far worse. I usually start the bike doing the two turn key method (though I don't know what that really does) and I like to think that it helps (but it doesn't). The bike used to occasionally stall coming from speed to a stop, so I turned the idle up to about 1500. But....since then, I've noticed at some stops, my idle will still drop to about 900 and nothing seems to change this except shutting the bike off and restarting it. This low rpm seems to occur on the same stints the stumble occurs. It might have done this prior to the idle change...I don't know. Also, is it normal for the bike to increase the idle once you put it in gear with the clutch in? It goes up to about 2k+. Is this the O2 sensor issue? Is it a fuel filter (wouldn't it happen at more varied rpms if it were). Please help, my passenger was even noticing how bad it was and that was with me trying to hide it with the clutch! Thanks. :warranty: Link to comment Share on other sites More sharing options...
KanadianKen Posted July 18, 2008 Share Posted July 18, 2008 Spark plugs bad? Link to comment Share on other sites More sharing options...
turtlecreek Posted July 18, 2008 Share Posted July 18, 2008 the 3-4k stumble could very well be the 02 sensor. 99cents to see if it is, so i would do it. by the way, is your throttle on/off transition jerky? if so, sounds even more like 02 would help. on the idle issue, seems as if a failing battery shows this symptom (i might be wrong). what are your voltage readings at the battery when: sitting engine off sitting engine idle 5k rpm Link to comment Share on other sites More sharing options...
Member Contributer Stumpthumper Posted July 18, 2008 Author Member Contributer Share Posted July 18, 2008 Yes, my on off throttle is very abrupt, but I took that to be fuel injection. I'll try the o2 sensor bypass. I haven't checked my voltages, but I will and will post the findings...don't have a multimeter handy but will get one. New spark plugs might help, but I'm not sure I see why it would cause the low idle. Link to comment Share on other sites More sharing options...
KanadianKen Posted July 18, 2008 Share Posted July 18, 2008 Is your throttle cable adjusted so there is very little slack? I adjusted Teachermans last week - made a huge difference. His bike was literally 600 miles old. Might not answer your low idle issue - but might help smooth things out from a start. Link to comment Share on other sites More sharing options...
Guest Posted July 18, 2008 Share Posted July 18, 2008 I have an 03 and I fought with it for years. surging and doing the hesitation thing your talking about. Here is the setup that fixed mine VTEC transition, surging and hesitation for good: Flapper connected PAIR disconnected plugged Powercommander with custom dyno tuned map DONE!!!! I was running cozye's map before the dyno tune and it came out smooth on the dyno except for the hesitation thing you are talking about. It showed up clear as day on the map. Hats off to cozye cause it was smooth except for that one section. They smoothed that part out in the map and gave it a couple more HP and now the bike is freaking sweet..... This was my last ditch effort before I sold it. Unfortunately for some of us it is the only way to smooth out the VFR. I'll try and scan the map and post it up. Link to comment Share on other sites More sharing options...
Member Contributer Stumpthumper Posted July 22, 2008 Author Member Contributer Share Posted July 22, 2008 tested the battery. After sitting for a few days, all off, battery was 12.6 volts. Key on, it dropped to 11.something. Once fired up, the voltage climbed to 14 and stayed there. Let it idle for 5 minutes (not even up to temp) and shut her off. Voltage slowly dropped to 12.88. Seems okay to me. Thoughts? :biggrin: Link to comment Share on other sites More sharing options...
turtlecreek Posted July 22, 2008 Share Posted July 22, 2008 tested the battery. After sitting for a few days, all off, battery was 12.6 volts. Key on, it dropped to 11.something. Once fired up, the voltage climbed to 14 and stayed there. Let it idle for 5 minutes (not even up to temp) and shut her off. Voltage slowly dropped to 12.88.Seems okay to me. Thoughts? :biggrin: while mine does this exact thing, 90% of folks on this board will say that your battery in not ok. most folks battery sit upwards of 12.8+ volts sitting still and dont drop below 12 when you turn the key on. take your batter in for a test just to eliminate that issue. Link to comment Share on other sites More sharing options...
Member Contributer Stumpthumper Posted July 22, 2008 Author Member Contributer Share Posted July 22, 2008 Ok, so here's the latest. I bypassed the O2 sensors with 330 resistors and took the bike out. It seemed to run pretty well until about 20 minutes of running and I felt another 4-5k hesitation (but very mild). A few miles later, I was on a parkway and as I came to the end of my exit I slowed down to about 5 mph and the bike REALLY hesitated and seemed like it wanted to die. It didn't though. I thought...hmmm, battery, so I kept the juice up. Had one stop before I got home and the bike started up just fine. Got home, shut the bike off and checked the voltage: 12.8. Started the bike and it slowly climbed. Revved the bike and noticed it would dip down into the high 12s occassionally. Held constant throttle in neutral at 4.5k and voltage climbed back up....and then let off the gas and the voltage dropped immediately to 12.6 (possibly lower for a split second). Fan kicked on and voltage went down a little more. I'm thinking battery now (could it be the rr), but don't know why a slightly lower voltage would cause the engine to stumble. Other tests? Any thoughts would be great! :rolleyes: Link to comment Share on other sites More sharing options...
Member Contributer Stumpthumper Posted July 23, 2008 Author Member Contributer Share Posted July 23, 2008 thoughts? Link to comment Share on other sites More sharing options...
turtlecreek Posted July 23, 2008 Share Posted July 23, 2008 thoughts? who knows...you're dealing with electronics and voltage converters....they give you a voltage spec for a reason. if you go outside of it, then some piece of electronics somewhere is not getting 5V or 12V but 4.7V or.....and doesnt like it and momentarily shuts down....just a guess, but like i said before, battery sounds like it should be tested. then test your r/r and your generator next. just my 2cents Link to comment Share on other sites More sharing options...
klrtovfr Posted July 24, 2008 Share Posted July 24, 2008 I have something similar going on with my bike, but may not be the same. Last summer It started to have a lot of backfiring during steady throttle most noticeable in 2nd and 3rd gears. Giving it gas made it very hesitant but once it got passed that second of hesitation it accelerated quickly like normal. I had the harness recall done this spring. It seemed to be slightly better, however my chain is about due to as it just rolled over 20,000. I haven't gotten around to replacing it yet, but Ive had a couple times that the motor decides to shut off two cylinders and I lose all power and sounds like my old single cylinder klr650. If I give it any gas it accelerates about as fast as a geo metro. I also have the original spark plugs so I might try those first. I do have the pair valve removed, snorkel removed, bmc air filter, and gutted stock exhaust, but it ran perfect for the first summer that I had these mods done. Anyone have a spare motor? Link to comment Share on other sites More sharing options...
DaveM Posted July 24, 2008 Share Posted July 24, 2008 thoughts? Do a search on surging - you will find two themes, 4-5krpm slight "pulsing" if you have o2 sensors in and then steady state "dead throttle" if you have the 02 sensor eliminators. Hours of keyboard time have been expended on these topics and will make for interesting reading. Once the battery, connectors etc are eliminated as potential problems, the common fix seems to be o2 eliminators installed and then cycle the key on, off, on before starting. I had symptoms almost exactly like yours - It works on my 02 and for many others as well. Why does it work? Magic? :biggrin: Link to comment Share on other sites More sharing options...
Member Contributer Stumpthumper Posted July 27, 2008 Author Member Contributer Share Posted July 27, 2008 Battery tested bad under load. New battery in and the thing is running better than ever (with 02 eliminators). It still died on my today after coming off the highway (and I have my idle set on 1400), but I feel this is unrelated to the other nonsense since it's always done that from time to time. Let's hope the new battery isn't masking another problem. Thanks for your help. Link to comment Share on other sites More sharing options...
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