Due to recent floods in Iligan city my bike was totaly submerged for about 6 hours. I have drained fuel tank i have changed oil and filters i have stripped and cleaned carbs. The bike starts and seams to run normal the as it gets hotter the rpm starts to rise then will drop onto 3 cylinders and rpm around 3000. Any ideas ????

 

David,
thank god you and bike are OK.
6 hours under water? EEEK!!!

I think I can say pretty much for sure that you won't find anyone else here who's had their CBR under water for 6 hours so any help we can give is going to be more than the usual logical guess work.

Can you tell us:
1. Was there much water in the oil when you drained it?
2. Did the engine turn over OK when you tried to start it? (If she sounded as though she was struggling on the starter it may suggest that you got water into one or more of the cylinders)
3. Have you thoroughly dried out the coils, leads and plug caps?
4. When it starts to run on 3 is the choke fully off?
5. Have you checked the breather pipe at the top of the engine to make sure it's not full of crap.

Other than these basics if the problem still persists see if you can work out which cylinder isn't firing when she warms up and re-check that carb for blockages in the main and idle jets. Also make very sure there's no air getting in between the carb and cylinder head. You may have a split rubber. A big leak could cause a cylinder to run so lean it stops firing.

Good luck. Please let us know how you get on. Fingers crossed that the waters have fully subsided.

 

thanks for reply yes water in oil water and mud in fuel tank and through all carbs, turns over easy and number 4 cylinder is misfire. i think i just ahve to keep cleaning all time i steamed out the fuel tank today and tomorrow i will for the umpteenth time strip and clean carbs and all air passages will keep informed. cannot post photo or u could see the top right hand corner of screen [poking above the muddy water

 

I wonder just how much crud got in to the combustion chambers through the open valves. How do the plugs look after running? It might not hurt to blow through the plug holes on the exhaust stroke with compressed air.

 

Thanks for ur reply,i have a compressor here, also floats quite well with air in tank so have done that, the plugs are very top end of normal light grey so I think i have just got to keep emptying fuel and clean carbs untill the prob dissapears

 

Well at last i have sorted the bike it runs a little hot at the moment but otherwise ok. The final problem was fuel contamination even tho i had pressure washed the tank petrol was still contaminated. The answer was a fuel filter. I got a large capacity filter and fiitted it behing airfilter box and under the seat support a snug fit snd works a treat, Thanks to those who offered advice When poss i will post before and after pics