CBR 600F4 1999 - 2000 Honda CBR 600F4 Forum

Backfire while attempting to start.

Thread Tools
 
Search this Thread
 
Old Jan 9, 2023 | 08:33 PM
  #11  
hamlin6's Avatar
Super Moderator
Joined: Mar 2013
Posts: 7,177
Likes: 404
From: Alabama
Default

Try adjusting your idle **** and see if that helps. Don’t turn it counter clockwise too many times as it come loose as there is no stop.
 
Reply
Old Jan 9, 2023 | 09:12 PM
  #12  
Lin's Avatar
Lin
Thread Starter
|
Member
Joined: Oct 2021
Posts: 35
Likes: 4
From: Utah
Default

Thank you but I have figured it out, the throttle cable itself was adjusted incorrectly. And I should've said that I turned the idle adjust all the way out and that it didn't do anything. My bad. It's running pretty good now and for the first time since I put the turbo on, the cooling system is holding pressure. I'm pretty sure that this was the reason the previous motor blew. And for anyone who felt bad about the motor that blew up, don't worry, it had almost 40k on it and was used as a stunt bike most of it's life so it was on its way out anyway.
 
Reply
Old Jan 11, 2023 | 01:48 AM
  #13  
Lin's Avatar
Lin
Thread Starter
|
Member
Joined: Oct 2021
Posts: 35
Likes: 4
From: Utah
Default

It's all back together and running great, no more stalling at idle. Thank you all for the suggestion/help. Now I just need to put a heavy duty clutch in to handle the extra power. If anyone knows a good clutch to get, please let me know.
 
Reply
Old Jan 11, 2023 | 08:43 AM
  #14  
hamlin6's Avatar
Super Moderator
Joined: Mar 2013
Posts: 7,177
Likes: 404
From: Alabama
Default

Great to hear. Thanks for the update.
 
Reply
Old Jan 14, 2023 | 10:23 PM
  #15  
Lin's Avatar
Lin
Thread Starter
|
Member
Joined: Oct 2021
Posts: 35
Likes: 4
From: Utah
Default

well, it has started running rough again. its worse this time. I've just tried replacing the spark plugs and battery, the plugs were not iridium but copper and the battery would only crank the bike for about 2-3 seconds, replacing these seems like it made it worse but i think it just got worse on its own. I just ordered a full rebuild kit for the carbs, im hoping its just that float needle that's letting to much fuel into the bowl.
the way its running right now, it will start just fine but it doesn't fire on all four consistently, if you rev the bike past 4k all cylinders will fire without fail, but anything under that and it completely drops 1 cylinder and fires about 80% of the time on another, the other two don't drop out at all. ive checked for vacuum leaks, fuel leaks and ive synced the carbs. while im waiting on parts to rebuild the carbs if you have any clue as to what else could cause it, please let me know. thank you.
 
Reply
Old Jan 15, 2023 | 07:25 AM
  #16  
hamlin6's Avatar
Super Moderator
Joined: Mar 2013
Posts: 7,177
Likes: 404
From: Alabama
Default

How does your petcock screen look, if it has one.
 
Reply
Old Jan 16, 2023 | 03:14 PM
  #17  
Lin's Avatar
Lin
Thread Starter
|
Member
Joined: Oct 2021
Posts: 35
Likes: 4
From: Utah
Default

its not a fuel delivery issue, it gets enough fuel. im thinking its one of the float needles letting to much fuel in. hopefully this rebuild kit fixes that. and it currently does not have an inline fuel filter, i plan on getting one though.
 
Reply
Old Jan 16, 2023 | 08:59 PM
  #18  
hamlin6's Avatar
Super Moderator
Joined: Mar 2013
Posts: 7,177
Likes: 404
From: Alabama
Default

Generally speaking, if it backfires through the carbs, it’s lean. If it backfires through the exhaust it’s rich.
Thats assuming everything else is in order.
 
Reply
Old Jan 24, 2023 | 03:12 AM
  #19  
Lin's Avatar
Lin
Thread Starter
|
Member
Joined: Oct 2021
Posts: 35
Likes: 4
From: Utah
Default

Well... Don't buy cheap coils. That was the problem this entire time. A coil is bad and was causing the miss. I unplugged it and although it was only running on three cylinders, the miss was gone. Moved the coil and the problem followed. Oh and don't build your charge pipes out of PVC pipe. It will work for a little while but eventually will deform and cause massive boost leaks. I'll be building it out of metal soon enough. Hopfully with new coils all the engine problems will go away but I have a feeling something is gonna pop up. I'll let you all know when I get the new coils. Fingers crossed.
 
Reply
Old Jan 24, 2023 | 03:14 AM
  #20  
Lin's Avatar
Lin
Thread Starter
|
Member
Joined: Oct 2021
Posts: 35
Likes: 4
From: Utah
Default

Oh and the reason I never checked the coils is because they are new and only have about 500 miles on them. Didn't think they would go out that fast but here we are.
 
Reply



All times are GMT -5. The time now is 08:05 PM.