So I'm looking at buying a 2001 cbr600 f4i. I inspected it and took a test drive a few days ago and it seemed flawless, extremely good condition. I just had the service history emailed to me, and the owner has had it in the shop 2 times in the last few months for poor running and backfiring, with smoke and black oily stuff coming from the exhaust (going off the invoices only). They messed about with the inlet and fuel system and cleaned the fouled plugs, and none of these issues were at all evident when I inspected the bike.Is this likely to be the fuel pressure regulator issue common to these bikes, or should I run screaming?

 

lol run, run like a raped ape! could be several things. i can tell you it will not be fun at all. probably costly too. could be rings, valves, valve guides/ seals, blown gaskets and/or all of the above... just going off what you stated. would need more details to get you on the right path. but it doesnt sound like an easy fix.

 

That's just going off the service invoices, was running perfectly when I rode it. I held my hand behind the exhaust when starting from cold, nothing coming out. Bike seems to run perfectly so I was thinking it was likely nothing in the engine internals but possibly a leaking fuel pressure regulator causing the spark plugs to foul?

 

Do what you want. Oil out the exhaust will have nothing to do with fpr. Check fpr by pulling the small vacuum hose off and turn on igntion to on position. Fuel will drip out fpr if its bad.if fpr is good then its running hella rich, look into that direction. Again oil out the exhaust is not an easy fix, it doesn't just go away. Tell em to take it down the road at night with you following, then let him accelerate hard over 10k rpm and see if smoke blows. See what color the smoke is and what color. If it smeels like oil or not. Or you can take it to a dyno shop have it on the machine and watch for smoke when they tach it out a few times. They will tell you what's going with it. These problems don't always surface when you ride it easy.

 

When my FPR went bad I was having a little moisture come out of my exhaust and it smelled VERY strong of gas when running. No one could answer to whether it is a problem or not without looking at the bike though.

Bike may be fine but on the off chance something is wrong I would pass unless there was a mechanic who could check it out for me before purchasing.

 

Being a life long mechanic, I would venture to say that if the shop that looked at the bike commonly worked on hondas, they would know it wasn't a fuel pressure regulator, or at least to look for that being an issue. Blow by into the intake with oil>> this would cause some issues and eventually flood one or more cylinder (normally the one closest to the vent tube supplying the blow by) with oil.. and once the fine tip of the spark plug saturates the misfiring begins. Unburned fuel mixes with carbon deposits, and can wash out a set of rings quickly causing yet more blow by and oil consumption. It just doesn't sound right. Not for an f4i.. I would pass unless you had a spare engine. My guess is more than 50/50 you would get bit.