Venturous Posted August 28, 2014 #1 Posted August 28, 2014 For some time my bike has had a mild decel pop and occasional backfire. This winter I did my valves which required I take off the carbs and reinstall them. Ever since, this condition has worsened. When I decel, my bike does a pop pop..pop..pop BANG. At Asheville Rally, I had several ducking for cover! The bike starts right up. The bike idles smoothly. Twist the throttle from a dead stop and it immediately takes off. No hesitation at all. Twist throttle at just about any speed and the bike responds without hesitation. So... as for as performance goes... all seems fine. I have noticed that this only happens when I am applying zero throttle. If I add even a little bit of throttle... it seems to stop the popping right away. What I have done so far: 1. Just resync'd carbs 2. Replaced the rubber caps that cover the sync ports. Mine were cracked some. 3. Sprayed some starter fluid around the carb boots while bike running to see if I could find a place that the RPM's changed in search of a vacuum leak. Found nothing. I'm running stock exhaust. K&N air filters and I opened the filter covers holes a bit. But I did that 10 years ago with no ill effects. This is all in the past year and half. So... any idears??
Flyinfool Posted August 28, 2014 #2 Posted August 28, 2014 A small exhaust leak? I am no carb guru by any stretch but I thought I remember reading that there is a decel enrichment feature in our carbs. So if at idle setting during decel the mixture is richened there may be some unburnt fuel in the exhaust, a leak lets in some air and it is hot enough to burn that excess fuel for the pops and bangs. This is just a pure WAG on my part. :confused24: :confused24:
eusa1 Posted August 28, 2014 #3 Posted August 28, 2014 read the thread in tech that shows how to block off the smog thermactor valves its simple and not permanent and should stop your concern. mike
bongobobny Posted August 28, 2014 #4 Posted August 28, 2014 Yup, either an exhaust leak or plugged up AIS system...
tomephil Posted August 28, 2014 #5 Posted August 28, 2014 My exhaust gaskets need replacing as I have the same problem. These are the gaskets directly under the seat.
Yammer Dan Posted August 28, 2014 #6 Posted August 28, 2014 My exhaust gaskets need replacing as I have the same problem. These are the gaskets directly under the seat. Have you ground the ears off the clamps so you can tighten them further??
eusa1 Posted August 28, 2014 #7 Posted August 28, 2014 lets not confuse what started as a 2nd gen question, with a slower 1st gen statement ha haha!!
Venturous Posted August 28, 2014 Author #8 Posted August 28, 2014 Whats the best way to check for exhaust leak? I have removed most of the AIS stuff and plugged the hoses years ago. Is that the same thing as the blocking smog thermactor valves you mentioned?
eusa1 Posted August 28, 2014 #9 Posted August 28, 2014 yes it is the same . if you want to check for leaks, start with cold motor and start up while holding a handful of shop rags or a towel over one of the exhaust tips and try and stop up the exhaust flow while listening or feeling at all the joints on that side for leaks. then the same on the other side. be sure and check at the welds in the middle of the head pipes where the y comes together.
Yammer Dan Posted August 28, 2014 #10 Posted August 28, 2014 lets not confuse what started as a 2nd gen question, with a slower 1st gen statement ha haha!! Weren't thinking, I thought you had the "1st Gen Education 101" I think I've figured out why the 2nd Gen is such a pig at slow speeds!! The 1st Gen might be also if you could get it that slow!! And where is the 2nd Gen question???
eusa1 Posted August 28, 2014 #11 Posted August 28, 2014 blah blah blah Dan!! I had a 1st gen in 1984 it was new and so was I i'm older and wiser now, and enjoy the comfort and the speed
billmac Posted August 28, 2014 #12 Posted August 28, 2014 do you have the idle too low? around 1000 RPM's should be good.
Venturous Posted August 28, 2014 Author #13 Posted August 28, 2014 do you have the idle too low? around 1000 RPM's should be good. I don't have a tach. I kinda guessed where it should be. Would that cause this? Maybe that would explain why adding even a little throttle makes the popping stop
Kirby Posted August 28, 2014 #14 Posted August 28, 2014 Gary, you may have a lean mixture. Back out all four idle mixture screws a 1/4 turn and see if it helps.
Prairiehammer Posted August 28, 2014 #15 Posted August 28, 2014 Gary, you may have a lean mixture. Back out all four idle mixture screws a 1/4 turn and see if it helps. With regards to the pilot screws on a Second Gen: backing them out makes it leaner? On the First Gen, backing the pilot screws out makes it richer.
Venturous Randy Posted August 28, 2014 #16 Posted August 28, 2014 Gary, you may have a lean mixture. Back out all four idle mixture screws a 1/4 turn and see if it helps. With regards to the pilot screws on a Second Gen: backing them out makes it leaner? On the First Gen, backing the pilot screws out makes it richer. Kirby is saying to back out the mixture screws to make it richer. RandyA
Prairiehammer Posted August 28, 2014 #17 Posted August 28, 2014 Kirby is saying to back out the mixture screws to make it richer. RandyA Yes, of course. I obviously didn't read Kirby's comment correctly. Bud Light might have something to do with my dyslexia.
Venturous Posted August 29, 2014 Author #18 Posted August 29, 2014 So, does someone who knows their RSV has the idle set to 1000rpm have a sound clip? After reading that idle speed could be my problem, I started mine and to be honest... it does seem kinda slow. But I have nothing to compare to. I did bump it up and will test it tomorrow.
billmac Posted August 29, 2014 #19 Posted August 29, 2014 lot of bikes have idle around 600 RPM but we need around 1000 RPM's I will try a sound test tomorrow. you can adjust on your test ride, just reach down and turn it up a little at a time and rev the engine up after turning up. you should be able to tell from the sound. when you sync the carbs you should turn the idle up some then back it off when your done.
Flyinfool Posted August 29, 2014 #20 Posted August 29, 2014 You could always get a tach something like this one. [ame=http://www.amazon.com/Inductive-Tach-Meter-Stroke-Engine/dp/B00DDK0XN8]Amazon.com : Inductive Tach/hour Meter for 4 Stroke Gas Engine New : Saddles : Sports & Outdoors@@AMEPARAM@@http://ecx.images-amazon.com/images/I/41W6n7EwTNL.@@AMEPARAM@@41W6n7EwTNL[/ame] Due to the venture having a wasted spark system you will need to divide the reading by 2 to get the actual, but it will do what you need and it is cheap.
Venturous Posted August 29, 2014 Author #21 Posted August 29, 2014 Well, using a simple grill lighter... I found some exhaust leaks. One on the right side Y pipe and both rear gaskets. https://www.youtube.com/watch?v=yli8szboIXA
eusa1 Posted August 29, 2014 #22 Posted August 29, 2014 YOU VIDEO IS SET TO PRIVATE AND CANT BE VIEWED?
Venturous Posted August 29, 2014 Author #24 Posted August 29, 2014 So now the question is... how the heck do you remove the chrome heat shield in order to repair that Y pipe leak??
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