Can't Get Past 8k rpm While riding
Posted: Mon May 27, 2019 5:19 pm
Hi all,
I'm New enough to road riding and purchased my first bike last year.
A beautiful black 1993 bandit 400 with just 12k miles.
When I got the bike the previous owner had installed a Remus Shorty exhaust and said that it hadn't been running perfect since. Unfortunately he had lost the original so i'm stuck with it. When I test road the bike it pulled perfect up until 8k rpm at which point it had a constant missfire until throttle was reduced allowing me to get as high as 8.5k but no higher (Approximately 20% throttle).
Long story short I bought it and when i got it home i started by cleaning the carbs in an ultrasonic cleaner. I notted down the jet sizes 102 mains with a 32.5 pilot, I set the float height to 14.5mm as the manual and forum suggested and the idle jet screw 2.5 turns out.
All o-rings and seals looked to be in good condition.
I reassembled the bike and took it for a test ride and lone behold it was fixed or so I thought. After a few days the missfire came back. I repeated this cleaning multiple times and it fixed it each time but for less and less time.
The last time I was able to get past 8k it was only 4 miles till it started missfiring again.
The past few times I cleaned them out I also cleaned out the tank. The previous owner had lined the tank with what looks to be epoxy, bits of which were flaking of and being pulled up against the screen of the tap.
But these last few times I have been unable to fix the missfire.
Things I've done
Spark Plugs Changed (NGK CR8EK)
Ignition Coils Changed
HT leads changed
Spark plug caps changed for NGK 5Kohm
CDI opened up, found some water and light corrosion, cleaned up and closed up (Possible cause?)
Ignition pickup changed
fuel line changed
Carbs Balanced.
Bike Starts cold with no choke and no throttle needed.
charging circuit puts out correct voltage as in manual.
carbs look absolutely spotless before and after cleaning.
Bike free revs to redline no trouble.
I will try to make a video of the issue to better describe it and include photos at a later date.
Any help is greatly appreciated as I am at a loss at this stage as to a fix.
I'm getting way to fast at cleaning these carbs for my own good.
I'm New enough to road riding and purchased my first bike last year.
A beautiful black 1993 bandit 400 with just 12k miles.
When I got the bike the previous owner had installed a Remus Shorty exhaust and said that it hadn't been running perfect since. Unfortunately he had lost the original so i'm stuck with it. When I test road the bike it pulled perfect up until 8k rpm at which point it had a constant missfire until throttle was reduced allowing me to get as high as 8.5k but no higher (Approximately 20% throttle).
Long story short I bought it and when i got it home i started by cleaning the carbs in an ultrasonic cleaner. I notted down the jet sizes 102 mains with a 32.5 pilot, I set the float height to 14.5mm as the manual and forum suggested and the idle jet screw 2.5 turns out.
All o-rings and seals looked to be in good condition.
I reassembled the bike and took it for a test ride and lone behold it was fixed or so I thought. After a few days the missfire came back. I repeated this cleaning multiple times and it fixed it each time but for less and less time.
The last time I was able to get past 8k it was only 4 miles till it started missfiring again.
The past few times I cleaned them out I also cleaned out the tank. The previous owner had lined the tank with what looks to be epoxy, bits of which were flaking of and being pulled up against the screen of the tap.
But these last few times I have been unable to fix the missfire.
Things I've done
Spark Plugs Changed (NGK CR8EK)
Ignition Coils Changed
HT leads changed
Spark plug caps changed for NGK 5Kohm
CDI opened up, found some water and light corrosion, cleaned up and closed up (Possible cause?)
Ignition pickup changed
fuel line changed
Carbs Balanced.
Bike Starts cold with no choke and no throttle needed.
charging circuit puts out correct voltage as in manual.
carbs look absolutely spotless before and after cleaning.
Bike free revs to redline no trouble.
I will try to make a video of the issue to better describe it and include photos at a later date.
Any help is greatly appreciated as I am at a loss at this stage as to a fix.
I'm getting way to fast at cleaning these carbs for my own good.