Gimpyxx Posted July 16, 2012 Share Posted July 16, 2012 I have a 97 bird with a Delcovic slip on exhaust and a k&n filter. I beginning to notice a surge only at steady throttle at highway speeds. The bike has almost 20k and has the cct replaced and has been cared for. I have also noticed the tach fluctuating when this happens. Anyone ever heard of this or any suggestions? Quote Link to comment Share on other sites More sharing options...
everydayrider99 Posted July 16, 2012 Share Posted July 16, 2012 Vacuum tubes. This is how mine behaved when I had a cracked tube. Does your FI light come on? Quote Link to comment Share on other sites More sharing options...
brianmacza Posted July 16, 2012 Share Posted July 16, 2012 I have a 97 bird with a Delcovic slip on exhaust and a k&n filter. I beginning to notice a surge only at steady throttle at highway speeds. The bike has almost 20k and has the cct replaced and has been cared for. I have also noticed the tach fluctuating when this happens. Anyone ever heard of this or any suggestions? How much does the tach fluctuate? Noticeable drop on the dial vs the revs you experience? My '97 hasn't ever surged - when the carbs were dirty it ran like crap, and then the RR and stator crapped out the most niticeable sign was my HIDs and clocks stopped working when the voltage dropped under 9V - it ran fine but was a concern Is the vent on your tank clear? It could be a fuel starvation symptom if its consistent (unless you can run hard at high revs ok) Doubt it would be plugs... Quote Link to comment Share on other sites More sharing options...
ironmike Posted July 16, 2012 Share Posted July 16, 2012 FWIW... This may seem counter-intuitive, but check the condition/adjustment of the drive chain. A drive chain in deteriorating condition or out of adjustment can manifest symptoms that sometimes mimic the feel of subtle engine surging. If your tach reading bounces around it's probably a ground issue. However if the tach reading stays relatively steady, that might be a clue that it's not the engine. Quote Link to comment Share on other sites More sharing options...
everydayrider99 Posted July 17, 2012 Share Posted July 17, 2012 I have a 97 bird with a Delcovic slip on exhaust and a k&n filter. I beginning to notice a surge only at steady throttle at highway speeds. The bike has almost 20k and has the cct replaced and has been cared for. I have also noticed the tach fluctuating when this happens. Anyone ever heard of this or any suggestions? AHhhh 97.... yea, your FI light is most likely not coming on. But still, vacuum tubes made my carbed Magna run funny like this. Quote Link to comment Share on other sites More sharing options...
Gimpyxx Posted July 17, 2012 Author Share Posted July 17, 2012 Ok I checked the battery voltage at 5k and its only 13.9. Isn't that low? Battery voltage off is 12.9 so that's ok.The chain is a bit slack so that was a good suggestion. Fixing that tomorrow. I'll check hoses too since I had the tank off to put in the k&n filter. Maybe a hose popped off. Quote Link to comment Share on other sites More sharing options...
EVLXX Posted July 17, 2012 Share Posted July 17, 2012 How long has the gas been in the gas tank ??? Quote Link to comment Share on other sites More sharing options...
redxxrdr Posted July 17, 2012 Share Posted July 17, 2012 Ok I checked the battery voltage at 5k and its only 13.9. Isn't that low? Battery voltage off is 12.9 so that's ok.The chain is a bit slack so that was a good suggestion. Fixing that tomorrow. I'll check hoses too since I had the tank off to put in the k&n filter. Maybe a hose popped off. Voltages are a little lower than mine, but not out of spec. On your chain...... Put the bike on the center stand. Then try to pull the chain rearward off of the rear sprocket. Advance the chain a little and try again. It should move the same distance in all places. Chains seem to wear more in certain areas. It can be good in one place and not in another. The stretched area will pull off the sprocket more. I'm at 31K on my chain, no rust on the wheel, still in the green, but it is stretched in some places and needs replacment soon. It gives a surging feel, especially at slow speeds. Quote Link to comment Share on other sites More sharing options...
Gimpyxx Posted July 17, 2012 Author Share Posted July 17, 2012 The gas is fresh, I ran out a couple tanks of different gas to make sure. The variation in rpm is 500. The needle will bounce back and forth. Cruising down the highway it feels like the bike starts slowing down but if you goose the throttle it takes off. Repeats every time. Quote Link to comment Share on other sites More sharing options...
TuffguyF4i Posted July 19, 2012 Share Posted July 19, 2012 So it is not the chain? did you check it? Quote Link to comment Share on other sites More sharing options...
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