I just bought a used '97 CBR 600 from a dealer. The dealer got the bike as a bank repo and knows nothing of it's history. I am unsure if the previous owner kept up with the maintenance of the bike so I wanted to check the air cleaner and the plugs. When I opened the air box the cleaner was horribly dirty. It was filled with dirt and parts of various insects. the pleats were atleast half filled with debris. I am suprised it ran as well as it did. It was a K&N so I cleaned it and re-oiled it. But I noticed some holes have been drilled into the carb intakes. I took pictures to decribe it better than I can.

This is the holes in the carbs and also some clear blue tape on the inside of the box corisponding to each hole in the carb. There used to be holes under the tape but they have been sealed from the outside.


This is the outside of the box where the holes have been sealed with something. looks plastic.


I'm not sure what this is either. The book says a sub filter goes here and it's a block of rubber.


This is the block, it says: "read instuctions before installing" on the bottom and "H062A0" at the top.


And this looks like something has been cut out where the sub filter goes.


So what do you think when in these holes and why is it not there now and sealed up? Thank you for any light you can shed on the matter.

-sXe

 

My first guess on the holes would be fornitrous.

 

I would say nitrous sounds about right, considering where the holes are placed.

 

Hmmm, that makes sense. But what about the rubber block? The manual says it's suppose to be a sub filter, but I cant see how a rubber block would filter anything so I am assuming this is not the sub filter that is supposed to be here. Plus why would a OEM part say "read instructions before installing"?

 

are the hole threaded?

Be thankful it looks like the guy knew what he was doing. Whatever it was..

 

No, but my friends father was over yesterday and I showed him the pics. He is knowledgeable in auto mechanics and has managed the local NAPA for over 15 years. He says that's all it could be is nitrous. He can think of no other possibilities. I'm not saying his word is gospel but I believe now with the opinions of the others on this forum, and his to collaborate, that is must have had nitruos on it in the past. It has a Yoshumira exhaust and a K&N filter. I wonder what others mods have been done. Possibly a carb re-jetting? I do know it is rediculiously fast and appears to run very well so hopefully there is no possible detrimental effects from this. Also when I got the bike the rear tire had no rubber in a 3/4 inch strip down the center. I was just cloth and there was a lot of balled up tire material all over the underside of the bike, no doubt from doing burnouts. I have also noticed that you only have to pull the clutch in maybe an inch for it to enguage, my old bike was not like this, not sure if thats normal. My friend also told me the rotors on the front were 'break away' rotors, not sure if thats stock either.

 

Sounds like he knew it was going to be repo'd and decided to strip the nitrous unit, sell it, and do a burnout with the tyre to finish it off. A pity, but anger can do strange things to people.
He probably loved that bike, too, so I would say you got a good deal.

 

sounds like you got real lucky man. Hmmmm, maybe a valve or cilynder job as well. Ports possibly. You have yourself an ex- racer.