Hi all, this is my first post. I have read allot of good stuff here but I am totally stumped as to what is wrong with my bike. Any help will be much much appreciated, my problems are as follows.

I recently bought a CBR600f (97) with 2800 miles on the clock as it hasn't been used for 9 years. Before I started it I drained the fuel tank and changed the oil and filter, fuel filter, coolant and replaced the battery.

The bike sounded like it was running on 3 so I stripped and cleaned the carbs (blocked slow jet found) It now runs better but is totally powerless under about 5k-6k then it suddenly takes off.(still has a twitchy tick over) I have tried bypassing the fuel pump and it was a little better.

The air filter and plugs look like new (and gapped correctly) but could well be the original ones, I went to buy new plugs but the bike shop talked me out of it as they have only done 2800 miles, will they be ok even if they are 12 years old?

All I can think of is some small internal blockage inside the carbs so an ultrasonic clean might do the trick (£80) but I'm not convinced as they look immaculate inside with no sigh of any varnish.

Thanks for taking the time to read this!

Mark

 

need to sync your carbs, for starters. then get back with us

 

I changed the plugs today and I am very suprised to say it has solved my problems . I didn't think age would affect a plug but it seems it does.

I did not touch any carb sync screws but I will be buying a sync kit soon to make sure

thanks again!!

 

Its good practice to sync the carbs anytime you disassemble and clean 'em

 

I purchased a 91 cbr 600 f2 2 days ago. It is my second bike but also sounds like its running on 3 cylinders. I just purchased it and I knew its a fixer upper. the guy I bought it from said he has changed the spark plugs but I think he was lying because I know what a vehicle sounds like when the plugs are fouled. I will confirm today as I will take the plastics off and find out. I'm really hoping that it is the plugs and not something else. I have lack of solid power until 5k then it rips.

 

hi mate, I would change the plugs as mine looked like new but still caused my bike to run like yours, if that does not sort it and your coil packs and leads are in good shape I would clean the jets in your carbs