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Discussion Starter · #1 · (Edited)
My '09 Brute {750 FI} has about 14 hours on it now and under a no-load cruise at just above idle it will occasionally lean-pop. Does anyones elses do this too? Runs FANTASTIC otherwise. Under a load she pulls perfect, no stumbles, just a ferocious PULL. Sounds to me like a mapping issue that has EVERYTHING to do with emmissions........
 

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Discussion Starter · #2 ·
My '09 Brute {750 FI} has about 14 hours on it now and under a no-load cruise at just above idle it will occasionally lean-pop. Does anyones elses do this too? Runs FANTASTIC otherwise. Under a load she pulls perfect, no stumbles, just a ferocious PULL. Sounds to me like a mapping issue that has EVERYTHING to do with emmissions........
Anyone? Just need to know if this is normal or not...............
 

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My '09 BF 750 does this exact same thing. Light load=popping (actually more of a sneezing sound) if I let it idle for more than say 1 minute it will sneeze then stall, if I nail it and let off abruptly it will BACKFIRE loudly and then stall.

So what is it mechanical (valves/ exhaust leak) or is it an EFI mapping problem? Just want to know so I don't get fleeced by the dealer when I take it back under warranty.

Other than this though I friggin love this quad, plows, muds, and wheelies better than anything I've ever ridden.
 

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Discussion Starter · #10 ·
My '09 BF 750 does this exact same thing. Light load=popping (actually more of a sneezing sound) if I let it idle for more than say 1 minute it will sneeze then stall, if I nail it and let off abruptly it will BACKFIRE loudly and then stall.

So what is it mechanical (valves/ exhaust leak) or is it an EFI mapping problem? Just want to know so I don't get fleeced by the dealer when I take it back under warranty.

Other than this though I friggin love this quad, plows, muds, and wheelies better than anything I've ever ridden.
Glad to hear {well for your sake NOT glad}, that someone else has this same issue. I thought this may be the case all along. No offense to the guys making the modules, but I WILL NOT pay to fix a "factory issue" at least while it is under warranty. I feel strongly that there isn't any mechanical issues, but a fuel mapping problem. Seen this many times in the outboard industry, and we have the capability to re-flash computers if the need should arise. Maybe if enough of us complain, Kawasaki may be forced to issue a service bulletin and have these units that are affected have the ECM replaced or re-flashed, maybe even pay someone to do it. Just a question....do any of the aftermarket guru's perform this service? By that I mean a factory ECM re-calibration for a stock motor? I'd like to see a poll to see how many FI Brutes are having this issue.....AND......they must be completely stock. Wadda ya think???
 

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Discussion Starter · #12 ·
They run this lean to pass emissions.
Agreed. BUT....the threshold of "lean" when the vehicle has consistent backfiring is not only a detriment to the mechanical components of the motor, it poses a fire hazard. I know the chances are slim, especially when the stock air box is in place, but I've seen flame arrestors and cleaners blown clean off from a serious backfire. Not to mention throttle plates that were bent over backwards. :eek: Mine does not do it as bad as "RAMBRUTES", but I am still concerned. Passing emissions is one thing, but to have running issues and potential property and persons damage is NOT acceptable. I'll call my Dealer and ask him if there are any "fixes" or if there are any in the works. If not, I'll ask to speak with a field rep and get his feedback.
 

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They run this lean to pass emissions.
Agreed. BUT....the threshold of "lean" when the vehicle has consistent backfiring is not only a detriment to the mechanical components of the motor, it poses a fire hazard. I know the chances are slim, especially when the stock air box is in place, but I've seen flame arrestors and cleaners blown clean off from a serious backfire. Not to mention throttle plates that were bent over backwards. :eek: Mine does not do it as bad as "RAMBRUTES", but I am still concerned. Passing emissions is one thing, but to have running issues and potential property and persons damage is NOT acceptable. I'll call my Dealer and ask him if there are any "fixes" or if there are any in the works. If not, I'll ask to speak with a field rep and get his feedback.
My BF only backfires really violently if I am working it really hard and then cut the throttle sharply. It most definately stems from a VERY lean AFR which only really became a problem with the cold weather. Cold dense air= richer fuel mixture required. I am an enginebuilder/machinist by occupation and can honestly say that yes a severe lean condition can most definately result in severe engine damage ie. burned pistons/valves. However with the very low compression ratio that the BF 750's are saddled with it would take a very determined operator to really hurt it that bad. Now don't get me wrong I am not saying I am not bothered by this--I AM!! It's friggin embarassing and I haven't notified the dealer yet because I know damn well they are going to tell me to bring it in so they can perform an oil change and little else and tell me it's fixed--not under warranty mind you. No, I'm pissed I love Kawie and it really ticks me off that I have a brand new EFI'd BF that runs the way it does, and that I will probably have to turn to the aftermarket for a solution. We should all write a letter to Kawasaki's ATV division and demand compensation whether it be a fix or $$. Is it just me or am I the only one I can rely on? Rants over. J.Rob
 

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Discussion Starter · #15 ·
They run this lean to pass emissions.
Agreed. BUT....the threshold of "lean" when the vehicle has consistent backfiring is not only a detriment to the mechanical components of the motor, it poses a fire hazard. I know the chances are slim, especially when the stock air box is in place, but I've seen flame arrestors and cleaners blown clean off from a serious backfire. Not to mention throttle plates that were bent over backwards. :eek: Mine does not do it as bad as "RAMBRUTES", but I am still concerned. Passing emissions is one thing, but to have running issues and potential property and persons damage is NOT acceptable. I'll call my Dealer and ask him if there are any "fixes" or if there are any in the works. If not, I'll ask to speak with a field rep and get his feedback.
My BF only backfires really violently if I am working it really hard and then cut the throttle sharply. It most definately stems from a VERY lean AFR which only really became a problem with the cold weather. Cold dense air= richer fuel mixture required. I am an enginebuilder/machinist by occupation and can honestly say that yes a severe lean condition can most definately result in severe engine damage ie. burned pistons/valves. However with the very low compression ratio that the BF 750's are saddled with it would take a very determined operator to really hurt it that bad. Now don't get me wrong I am not saying I am not bothered by this--I AM!! It's friggin embarassing and I haven't notified the dealer yet because I know damn well they are going to tell me to bring it in so they can perform an oil change and little else and tell me it's fixed--not under warranty mind you. No, I'm pissed I love Kawie and it really ticks me off that I have a brand new EFI'd BF that runs the way it does, and that I will probably have to turn to the aftermarket for a solution. We should all write a letter to Kawasaki's ATV division and demand compensation whether it be a fix or $$. Is it just me or am I the only one I can rely on? Rants over. J.Rob
Hey Ram.....just got done talking to my Dealer and he didn't give me any grief at all. As a matter of fact, he said he'll call Kawi and run it by them. He also stated that he has a 650 {although it is carb'ed} that he brings out front everyday for display that runs horribly lean. Sounds like he knows our pain. He is supposed to call me with an update and as soon as I hear from him I'll let you know the outcome. I did mention this web-site along with others with the same issue. I agree, this is most CERTAINLY a lean condition and can be easily rectified......let's see if they'll come to the plate.....I don't plan on backing down until it's fixed....B)
 

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You are probably going to find that Kawie won't be that helpful.They will tell you that this is normal and it won't hurt anything and you have to live with it because it is for emissions.That is the response from most factories.They couldn't get away with it with cars because the number of car owners is too large for them to getaway with it but motor sports is a small number comparedto cars.I worked on Harleys for around ten years and back before they went injection they had the same problem.They had a lean cough and ran so lean that they would detonate on a hot day from they extra heat of the lean condition.If you read the owner"s manual it told you this was normal and wouldn't hurt anything.If you complained to the dealer they would offer to sell you a hundred dollar Dynojet jet kit and labor to install it but wouldn't do anything under warrenty because the factory said it was normal.I don't care what any factory says a lean condition that causes enough extra heat to cause pinging is causing damage.It may not blow up tomorrow but it will cause damage.
 

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Backfire

Hey guys my 08 750 brute force fuel injected does the same thing as well
anytime you let off the gas it pop/backfires. now i have open up my valve and check to see if they tighten up. did this twice. check my air filter for any dirt. change my plugs. check the exhaust for leaks. Nothing mecanical was found to be abnormal. took it to the dealer for this concern. and well let's just say it is still happening insted of helping me out they wanted to sell me a 10 hour service. knowing it wouldn't fix my concern and not willing to pay them 400$. the insisted it was a poor maintenance issue.
LOL i highly doupt it since most of us or having this problem. i will have to wait and see if kawasaki come out with a reflash for the ECM.
Other then that it's an awsome bike wouldn't ride any other quads than that one.
 

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Discussion Starter · #20 ·
UPDATE!
Ok...my Dealer called me back today and told me he discussed it with Kawi. Come to find out, there are "air" screws on the throttle bodies that help control low speed emmissions {capped off!!!}...read...LEAN. They're location is not in the service manual, nor is it mentioned anywhere. He said with a simple turn "clockwise" it may solve my condition. Obviously we discussed the possiblity of any air leaks, loose clamps etc., and I assured him that was not the case, double checked all that. Sounds good to me so far......I'm gonna go after this myself, probably next week and I'll let you know how involved it is......
 
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