I recently purchased a 97 CBR F3. Has around 11,400 miles on it. I recently had it serviced. Bike had sat for about 3-4 years. Fuel had been drained while it sat, but tank hadoxidized and had to be treated and cleaned, then the following was done- fuel system clean, carbs cleaned, new plugs, oil and filter change, new air filter, fuel filter, tires, tune up. I put about 200 miles on it, it ran great, then after sitting for a day when I went to crank it up, it turned over, fired up, ran terribly then quit. Eventually I could not even get it to fire up. I replaced the plugs with new ones, it started right up and ran well. I have put about 60 miles on the new plugs, but have notice that when running at idle it back fires slightly. I have read many forums on here and I am beginning to think there are some similar characteristics which my F3 possesses that may be common in the F3's.

The bike has a Two Brothers Carbon slip on pipe in case that is a question - the plugs the shop that worked on the bike had put in the bike were NGK CR8EH9. I was unaware of this and bought what the manual indicated which were CR9EH9 plugs. I did not notice any backfire with the CR8's that I can remember. Can anyone tell me what the appropriate plug is that I should be running in this bike, and can anyone help me with regard to the fact that the first set fouled out within 200 miles?

Also, with regard to fuel, First 200 miles gas was 93 octane from Hess first, then Gate. Fuel in it now is Amoco 93 Ultimate. Iwas told that was the best fuel to burn in these. This current set of plugs however has the first 60 miles with the Gate gas. Again, not sure if this really makes much difference, just going on what I have read and have heard and wanted to provide as much info as possible.

Thanks -

 

NGK CR9EH9 are the correct plugs, don't think the slip-on will change that. Can't explain the fouling. Are you running the bike for short intervals? I will look more in the Honda factory manual.

Edit: Manual says that if the engine is hard to start or will not start, and the plugs are wet, then:
1) Fuel-air mixture too rich
2) Carbs are flooded
3) Choke excessively closed
4) Cylinder Flooded
5) Air cleaner dirty
6) Faulty EVAP purge control valve (Cali model only)

Not sure how much that helps but it's a start