CBRXXRAGE Posted February 5, 2005 Share Posted February 5, 2005 I have a 97 and it has a full system Yosh. dont know if it was jetted bought it used. What does this sound like to you guys. Accels great no miss or stumbles has a strong exhaust smell though. Any help would be great, Thanks in advance. Quote Link to comment Share on other sites More sharing options...
Byrdman Posted February 5, 2005 Share Posted February 5, 2005 Correct me if I'm wrong, but I think the backfiring on decel is caused by a too rich jetting condition. The extra unburnt fuel is ignited in the exhaust stream and causes the popping. Quote Link to comment Share on other sites More sharing options...
K9XX Posted February 5, 2005 Share Posted February 5, 2005 THought it was the opposite. On my XR650 when I decel and it pops, I richen it and it goes away. I can't remember how it was on the Bird, I jetted it a couple of years ago now, and it was rich at first, as evident by black smoke puffs here and there. I don't recall any popping. I would rather run a lil richer then a lil leaner. Seems to be better for engine life if you have to pick one :wink: Good luck! Quote Link to comment Share on other sites More sharing options...
cbrxxquad Posted February 6, 2005 Share Posted February 6, 2005 Correct me if I'm wrong, but I think the backfiring on decel is caused by a too rich jetting condition.The extra unburnt fuel is ignited in the exhaust stream and causes the popping. this is correct dynajet program charts show the bird is way rich from the factory down load the charts on the web and most are leaner than stock with aftermarket exhaust you really have to have a freeflowin pipe to need richer and almost all aftermarkets are notmuch better if more air equals more fuel Quote Link to comment Share on other sites More sharing options...
CBRXXRAGE Posted February 6, 2005 Author Share Posted February 6, 2005 Whats dynajets website? I talked to 4 people and two said lean and two said rich. Quote Link to comment Share on other sites More sharing options...
cbrxxquad Posted February 6, 2005 Share Posted February 6, 2005 http://www.powercommander.com/supphonmaps.shtml edited dont know if this is gona help you without the programer and program i dont know how to show the settings on here maybe somebody can help me to post the different charts Quote Link to comment Share on other sites More sharing options...
XXTi Posted February 6, 2005 Share Posted February 6, 2005 I'm with K9XX on this one. My old KLR650 popped on decel until I richened the mixture. I'll admit the rich mixture/unburned fuel seems most logical, but it didn't work that way for me. Quote Link to comment Share on other sites More sharing options...
Pete in PA Posted February 6, 2005 Share Posted February 6, 2005 Try disableing the secondary air supply system. It injects air into the exaust at the head for emissions. Check for exaust leaks. Any air getting in will allow the popping. richen up your pilot screws. Turn them in till they lightly seat, then out 3 turns. Popping on decel. is a lean condition with the throttle off. Since you have a strong exaust smell I would say there is a jet kit in it. Probably too rich in the mid range, too lean at idle. Quote Link to comment Share on other sites More sharing options...
blackhawkxx Posted February 6, 2005 Share Posted February 6, 2005 I had a 85 GT Mustang that I put a full exhaust system on (headers to tailpipes) and it would backfire when you backed off the gas. I removed the smogpump (air pump) and it stopped. I'm thinking it's lean. Quote Link to comment Share on other sites More sharing options...
Red J Posted February 6, 2005 Share Posted February 6, 2005 Lean. Replacing the pilots with 45s will stop the popping. 99103-MT2-0420 - 6.77 each at hondadirectline.com J. Quote Link to comment Share on other sites More sharing options...
CBRXXRAGE Posted February 6, 2005 Author Share Posted February 6, 2005 Thanks for the info I will start looking at all the info supplied. Quote Link to comment Share on other sites More sharing options...
Keith Posted February 6, 2005 Share Posted February 6, 2005 I'll add another vote for too lean. A buddy with a 'busa had this popping problem after he put a full system on it. He had a PCIII, so he asked Dynojet tech suppport for help; they told him to richen the closed throttle mixture by quite a bit across the entire RPM range. That solved the problem completely. Quote Link to comment Share on other sites More sharing options...
demon Posted February 6, 2005 Share Posted February 6, 2005 definately lean. In your exhaust, fuel won't burn withour air. If you have a rich condition, all the air is being burnt. If you have a lean condition, all the fuel is being burnt. Look for exhaust leaks as well as doing what Pete said about the carbs. You might even look into blocking off your PAIR valve which lets air into your exhaust for emission reasons. Looking at maps for fuel injection won't help you a bit when messing with carbs. They work completely and totally different. Quote Link to comment Share on other sites More sharing options...
nickc2s Posted February 6, 2005 Share Posted February 6, 2005 Factorypro.com for carb tuning info Quote Link to comment Share on other sites More sharing options...
Keith Posted February 6, 2005 Share Posted February 6, 2005 You might even look into blocking off your PAIR valve which lets air into your exhaust for emission reasons. If J Red would ever get these done, I'd get a set. :poke: :grin: Quote Link to comment Share on other sites More sharing options...
Keith Posted February 6, 2005 Share Posted February 6, 2005 Looking at maps for fuel injection won't help you a bit when messing with carbs. They work completely and totally different. My reference to maps was to make a point about lean vs. rich, not that EFI maps would help with his carb problem. Quote Link to comment Share on other sites More sharing options...
StPeteXX Posted February 6, 2005 Share Posted February 6, 2005 I have the same exhaust and problem. I want to do a jet kit anyways. Would that also solve the problem? What performance benefits would I see from jetting? Pro's and con's?? Rich Quote Link to comment Share on other sites More sharing options...
tomek Posted February 6, 2005 Share Posted February 6, 2005 Carb bikes when tuned for absolutly the best power will pop a little on decel.Almost all race bikes are F.I. this days but back in the carburator era there would be a lot of poping,even backfiring when they were slowning down for the corner. Yea,you colud check for exhaust leaks,try to richen your pilot circut,but just because your bike pops from time to time it does not necesarly mean it is running lean.Read your plugs first before you start messing with jetting. Quote Link to comment Share on other sites More sharing options...
XXTi Posted February 6, 2005 Share Posted February 6, 2005 It's much easier to richen your pilot screw positions vs. changing jets. Try it first and see if it cures your trouble. Quote Link to comment Share on other sites More sharing options...
Red J Posted February 7, 2005 Share Posted February 7, 2005 You might even look into blocking off your PAIR valve which lets air into your exhaust for emission reasons. If J Red would ever get these done, I'd get a set. :poke: :grin: Yes, I'm needing to get back on this. Plenty of excuses, but you don't wanna hear them. The short is: they're coming. J. Quote Link to comment Share on other sites More sharing options...
bartonmd Posted February 7, 2005 Share Posted February 7, 2005 The popping on decel is from what is known as "Choke Flow." Choke flow is when the engine wants a BUNCH of air (higher rpm than idle) and is getting almost none (closed throttle). The air accelorates to close to the speed of sound going through the little throttle opening. This is not very condusive to proper mixing of fuel/air mixture. The only way to get rid of the popping is to make it WAY rich at idle so it doesn't have to mix really well because there's so much fuel. It's kindof annoying, but it isn't hurting anything more than likely. Trurotor2: I beleive it was talking about the FI maps: The FI maps are really rich at low throttle position to get around using the computer controlled secondary throttle valve. They make it rich at low throttle position so the throttle response is not uncontrolable. Carbs aren't really like that at all. Mike Quote Link to comment Share on other sites More sharing options...
porterb123 Posted February 7, 2005 Share Posted February 7, 2005 The lean guys have it right. I built and tuned a CB1100F for a good while...even addaed an Autometer air fuel meter by welding a bung on the header collector with a heated Bosch O2 sensor. Turning out the oilot screws a little at a time until decel. pop is gone. That bike ran best a little on the rich side but in general the best spot was as lean as I could get it...still rich though. Porter Quote Link to comment Share on other sites More sharing options...
Pete in PA Posted February 7, 2005 Share Posted February 7, 2005 Just so everybody understands. The best A/F ratio for emissons is not the best for power. For emissions, you want enough air to burn all the gas per combustion cycle, for power you want enough fuel to use all the available air. power=12.5 to 1 emissions =14.7 to 1 Quote Link to comment Share on other sites More sharing options...
StPeteXX Posted February 7, 2005 Share Posted February 7, 2005 We no longer have emissions testing here in FL. What can you recommend tuning for that? Rich Quote Link to comment Share on other sites More sharing options...
cbrxxquad Posted February 7, 2005 Share Posted February 7, 2005 the reason i was referencing the charts for the bird from powercommander was to show the changes from stock settings to stock bike after dyno to aftermarket pipes. was very intresting in the rpm and throttle settings and wheither fuel was removed or increased at that point,especilly rpm at o throttle one note they dont change the aap chart for this they change the mp for less than 10 % throttle sorry about the confusion was reference info as to what works on the dyno on the bike Quote Link to comment Share on other sites More sharing options...
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