Hello to all! Mid-Level rider on my first CBR. The F4 was just kind of an impulse buy to get me by for the summer but the thing has kind of grown on me. Bought it with a few imperfections (Plastic), no mods really exceptanM4 slip-on which I have to say sounds pretty decent when you wind it up! It seems to be a real solid bike with just 13k on it. I've been skimming the forums for Tech stuff and have learned a lot of inside stuff concerning these bikes, however, a few things aren't totally clear to me. My questions... As I've had the thing tore apart a bit, the first thing I noticed is that the vacuum line from the back side of the carbs which runs to be what looks like some kind of diaphragm/regulator has been disconnected from the diaphragm/regulator and capped off. From what I understand this is some kind regulator. For what? And is this commonly disconnected? 2nd question... Is there anyway to calibrate or adjust the speedometer? It is off 10mph at 65mph. All and any info and opinions are much appreciated!!

 

Well I found out it's the air injection control valve which is disconnected on my bike. However, this sounds like something that could negatively affect performance but I can't really seem to tell. But I suppose I've only ridden the bike this way. Anyone shed some light on to this valve, should I just hook it back up and see what happens?

 

To fix the speedometer problem you want a product like the speedohealer Honda I. It costs about $100, and takes about 20 minutes to install - but allow an hour the first time.

I've noticed a few pipes off on mine... I reconnected them and can't tell the difference. Can't help you there...

 

not sure on the vaccum hoses, mine are all connected...and I dont mess with that b/c vaccum hoses can cause some weird problems when there not connected/connected incorrectly.

as far as the speed odometer off, you would need a speed healer that you can find here runs right around $100 everywhere io have found one. I am getting ready to put diff sprockets on my bike which is most likely why yours is off.

this your first sportbike? I rode a cruiser before I switched to sportbikes, I still like cruisers, but I love my cbr

 

2nd sportbike but first Honda sportbike. I'm pretty pleased with it. Yeah I've heard bad things about the other vacuum lines being hooked up wrong, used for sycnhronizing the carbs I think? I'll hook it up and see what happens. Good info on the speedo healer. Actually the only thing that makes me nervous about the bike is that the guy before me threw a 190/50 Michelin PP rearon it. It seems to handle fine and I can flick it farely fast side to side but just knowing it's not the right size tire for the rim makes me wary!

 

I wouldnt worry about the tire, they say the stock tire sizes are the best for maneuvering the bike. as long as it doesn't rub should be fine. you can always go wider on a rim, never want to go narrower is what my buddy always told me when he use to manage a tire shop. I guess thats when you would have to worry about the tire making a good seal.