Honda CBR 500 Riders Forum banner

2021 cbr500r motor keeps cutting out when accelerating!

3K views 13 replies 7 participants last post by  ADIOS600 
#1 ·
Hey everyone, I was hoping maybe someone can point me in the right direction with this stuttering issue I've been relentlessly trying to pinpoint on my 2021 Honda CBR500R ABS everytime I give it throttle and began climbing RPM'S to gain more speed, whether im in stop & go traffic or just simply need to pick up my overall speed while keeping up with traffic, my motor will start cutting on & off between 3,000-5,000 RPM's in the rev range when im accelerating. I ended up ordering a brand new fuel pump from honda and replaced my old fuel pump with a brand new one which has completely fixed this issue and have been without any problems for the last 2 weeks or so, up until the last 3 days ago when i was on my way home from class, and the sputtering came back out of no where without any warning and this time it came with a vengeance on me because I almost immediately started loosing power to the wheel on top of it... so, I had to pull over and get it towed shortly after that. I did get caught in rain for a good 10mins on my way to class earlier that day, but it was not to bad and have never had issues before. Before my motor stopped running on me,It felt very similar to a clutch going out or when a car's transmission goes out and all you can do is rev up RPM's but your not actually moving hardly at all with any power. however in this case, it wasnt my clutch that was going out. After this happened to me, I havent been able to get my bike to turn back over again ever since. You only can hear the starter but it just wont crank up now so, it has me set on my fuel injectors, ignition coils, or spark plugs being the potential issue here. I ended up buying seafoam fuel injector cleaner and emptied my fuel tank out and replaced it with a clean gallon of unleaded fuel as I normally would use to fill up my tank with and now it started back up again thank god. However,theres a small catch.. i have to give it some throttle while starting my bike because the minute I let off the throttle, my RPM's drop well below the normal 1200 RPM idle level and just completely stalls out on its own if i dont maintain a little throttle at the sametime while starting it up. Once I get it started and give it a good rev and keep fuel flowing, I can let off the throttle and the bike maintains a somewhat sluggish idle rpm level. I dont want to ride my back yet until im positive its back to normal functions and cause any potential further issues. The other snag to this is, I use my cbr500r daily as I dont have a car at the moment and really need help as to what this issue could possibly be with my bike... I just rolled up on 10,000miles on the odometer and currently have stock OEM muffler / headers/ and air filter are all the factory stock parts. However, I did have a dynojet power commander 5 installed for the last 4,000 miles or so. I also had a Yoshimura R-77 carbon fiber slip-on exhaust for the same amount of time as i had the dynojet power commander installed. The dynojet was installed with the correct software download for my make year and model bike so theres nothing i can see as a potential problem now because of it. I did however remove it and my slip on exhaust is removed and replaced everything to stock again afraid of not knowing what had caused this issue im having. im really hoping someone else possibly might have a idea what im looking at here and what I should try replacing!
 
See less See more
#2 ·
Well if it was me I would remove the tank and double check you have no debris or water in the tank. While you are at it remove the spark plugs and check to see if it is running equal on both cylinders, ie plug colour in case you have an ignition fault. Then come back to us. I cannot understand why you are having this problem as these bikes a very reliable.
 
#3 ·
Did you installed new exhaust header gaskets after header swap? Is oxigen sensor installed? If not I strongly recommend to use new header gaskets and tight the header bolts to it's nominal torque. Any oxygen leaks in header will lead to erroneous oxygen sensor reading (ECU thinks the engine runs lean) and it leads to overly rich fuel mix or lean protection cut off.
 
#4 ·
Yes I just installed a brand new honda exhaust header pipe and two new gaskets along with it a week ago. I just changed spark plugs yesterday and they were black at the tips so I was running rich for a while I believe. But nothing changed as far as the problem im still having. Ever since I put fuel injector cleaner in my tank, I finally can start the bike but only if I'm giving throttle at the Sametime, otherwise it just stalls out... The throttle opens up air intake and that's what will allow my engine from stalling in idle... so now I'm wondering if maybe thats the category I should be looking into
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top