engine problems

alright what do u guys think.. my buddy's bike is having issues

he has a 1991 CBR600 F2.... and when u mash the throttle it takes forever and day to wrap up.. and wont go past 10K...

it gradually got worse from being able to top out at 150 to topping out at 120 in a matter of a month...


is it

1. Valves need Adjusted BADDDD

2. Carb's need Cleaning BADDDD

3. Both

personally i think its the valve's but i wanted more opinion's... ones that didnt have the though of money in them

to save money try overdosing it on Redex or any high strength injector cleaner. rev the crap out of ir when you do. put it in neutral and just snap open to full the throttle and see after a few go's if she gets better

well he didnt do the injector cleaning thing.. he took it in to have the valve's adjusted.. turned out that they were fine but 1.. was off slightly.. BUT the spark plugs were toast... the guy went ahead and replaced them.. runs perfectally fine.. now he stays right along side me :)

ya, i was gonna say spark plugs, since few of the cylinders may not be firing.