hey all i have a 95 900rr that i bought with a blown motor. i replaced the motor with one out of a 97. replaced the motor and carbs. it will be running fine and then all of a sudden it seems like it floods it self and and wont restart. i have to let it sit for about 15 mins. before i can get it to start back up. does anyone have any ideas on what might be causing this to happen.
thanks

 

I had that exact problem jrode. The major problem for mine was that I was using the incorrect fuel in my 93 CBR900. The CBR900 seems to run better on lower octane fuels. Here in South Africa we have two main fuels, Lead Reaplacement(low octane) and Unleaded(higher octane). The Lead Replacement fuel is made for older cars and carries a lower octane index than Unleaded fuels. Running higher octane fuels doesnt give more power, it is specifically made for engines with higher compression, therefore older cars/bikes run much better on lower octane fuels.

A noob told me to run unleaded and I didnt know better so I dumped my fuel and put in unleaded. When she was cold she ran like a charm but once she got warm, her first gear bogged down and I hardly had any power in first. If I idled her long enough she started to sound like a twin and then swtich off. She wouldnt start again until I let her cool off for a while. Then she starts fine, just to repeat her process.

So i took apart my carbs for a clean (only because it was her time for a clean), cleaning everything thoroughly. Then reset my pilots to the correct air/fuel mixture. My sparks were new but soiled due to the crap spark of the Unleaded fuel to I had to clean them. Carb cleaner and wire brush worked like a charm. I then dumped out the Unleaded fuel and then put in the Lead Replacement fuel (lower octane) back in.

She fired up right from the start. I let her idle for a while to warm up and then rode her around, close to home, to work the Lead Replacement back into the system. She pluttered a little as she worked out the reamaining Unleaded fuel and then she was back to her great self again.

Another thing that might cause that problem is defective ignition coil. As the bike warms up a defective ignition coil would start to degrade and then your bike should start to sound like a twin and either switch off or run terribly.

Tru using lower octane fuels first before looking at the coils, that would be a good start.

Hope this helps jrode