Hi, I recently picked up my first bike, a 96 cbr 600. I have a few questions about some issues I have noticed. The spedometer is off by a significant amount. I did some research and i know it should be off by alittle bit but to do 45mph my speedometer has to read between 55-60 mph. Im not sure if its an actual issue because of the amount it is offor if a speedohealer would take care of it. Problem 2- Sometimes the bike wants to get stuck in neutral and does not want to downshift to first. If I pulse the clutch once it will go in just fine but the bike will kick very slightly.This is just an occasional problem, normally it shifts fine.Is this normal or is something out of adjustment or in need or replacement? Problem 3- I have a rough idle. I dont know when any of the maintenance was done to it.The tach changes about300 +/- RPMs. Im not sure if maybe the carb needs adjusted, if it needs a tune up or if bikes just have a rough idle. Keep in mind the bike has 38,000 miles. I know alot about cars, I was a mechanic for awhile, but bikes are a whole new scene to me so any help at all is appreciated. Thanks, Brian.

 

Also, any suggestions or tips on maintenence (such as what kind of oil filter and filter #, how much oil and what kind, etc) and such would also be greatly appreciated. Thanks, Brian

 

I just got a 95 with 31,000 miles on it. The idle was all over the place, so I got some Seafoam injection cleaner and Gumout spray cleaner. I put half a bottle of the Seafoam in with a fuel tank and high octane, and sprayed the carb's clean, now it purrs like a kitten. Nice even idle. I replaced the spark plugs last weekend and it actually idled a pinch lower, about 100rpm, and runs even better.

Somewhere along the line a previous owner may have swapped out the sprockets for a different ratio and thats why the speedometer is so far off. Count the teeth on the front and rear sprockets. Factory is 14 front, and 45 rear. I'd guess you probably have either 15/43 or 16/41. A speedohealer would fix things up.

If your sitting still the tranny may be in a spot that wont shift gears. Sometimes rocking a little gets things loose. Mine kicksa little when engaging first, I've been told thats normal.

 

Wow, thanks for such a fast and detailed answer! When you replaced your plugs and wires, what kind of plugs did you use? Can i just go to autozone and get some standard plugs? I want to do a complete tune up tomorrow but im not sure of which plugs, wires, oil, filter and air filter to use. Im also going to clean up fuel system as you suggested. Thanks for your help! -Brian

 

I went to Advance Auto and got NGK Iridium IX spark plugs, part number 6216. They are expensive but well worth it. I inspected and kept the wires that were on the bike. I use Rotella T 5w-40 Full synthetic oil with fram double guard oil filter. I have a K&N air filter.

 

Scrufdog, when you sprayed the Gumout, did you pull the carbs, or just spray into the openings? I ask because I had Seafoam in my fuel and it seemed to work great. Then i've put a few tanks of regular fuel back through and I noticed that I had to adjust the throttle stop again because the bike started running rough again and the RPMs were way too low. I think I'll need to pull the carbs over the winter for cleaning, but if I can use the spray i'd like to try that.

 

I sprayed into the carbs. Sprayed around the ourside and inside, till everything was silver again. I then cracked open the butterflies and sprayed a bunch down into the intake. Let everything soak for about a half hour while I did other things, then resprayed everything all over again, and into the intake again.

Hit the starter a couple times, wouldnt start, then crack the throttle open a little and cranked it again. Fired up rough. Let run about a minute, then started revving it up and down quickly, then idle a moment, then a bunch of quick high rpm snaps. Blew out all kinds of black/gray smoke. Got it idling again, then went for a 10minute ride. Kept the rpms up to get rid of anything else. Got back, re-adjusted idle to 1400, been spot on ever since.

 

You called it, the previous owner swapped out the gears to 15/43. Is that ratio for acceleration or top speed? Thanks, Brian

 

acceleration

 

I have 16-41 on mine, just installed em like 2 weeks ago..woot!