Well I recently bought an F3, and when I got home with the bike, i noticed that the recipt from a motorcycle shop claims that it's compression is 140-150-90-160. Now the 3rd number seems lower but the bike still runs fine.

Do you think it is a bad CCT? or bad valve job?

I gave the shop a call and they say they that i might have to replace the cams, or piston rings. The bike has about 18,xxx so maybe it missed the valve job.

Wat do you guys think?

 

No, I don't think at that mileage it could be rings unless the bikes was realy abused. Most probably it's valves.

Just to be certain you can do the oil test.
What you do is poor a teespoon of oil down the sparkplug hole and then test the compression. If the compression comes up significantly then it's rings but if it stays the same it's valves and you'll have to take the head to a engineering shop.

 

I don't trust your shop much...buy cams...? at 18K.....I'll need your left kidney and pinky finger too.

Did this shop do a valve adjustment...? If valves are "tight" for a long time they begin to build up carbon on the sealing faces. This will clean off after the valve clearances are reset, but the clearances drop fast on those valves and you should reset them again sooner than the standard adjustment interval.

If you buy a compression gauge of your own ($40), you can plug an air hose on to the supplied hose...if you hear the air blowing out the exhaust pipe, it has a valve thats leaking. There is a specific tool for this, with two pressure gauges and is referred to as a leak down test. It offers a lot more info than a compression test. Numbers of 4-8% are ok...when you get above 10 something needs attention....on these bikes is is virtually always valves.

Rest assured, I have seen MANY CBR's and other rockets in general go well into the 40K.....18K is NOTHING.

A valve adjustment is cheap on parts (hot cams makes shims for cheap, OEM shims are NOT cheap), but takes a few hours....a shop will rape you for it....a couple hundred at least...since the cams have to be removed.

A valve job on a motorcycle cylinder head is under $200, but its "labor intensive" to remove the head.

 

Okay, so what i'm getting from you guys is that
1) Don't trust that shop again. and
2) I should get a valve job done.

Also along with the recommendation from that shop, they state that the CCT could use a replacement. Should I get both the CCT and the vavle adjustment done?

I've never done the vavle adjustment or CCT so I really don't want to do it by myself. I would like to learn but i want to be shown how and then do it. It's easier for me that way.

 

I would look for an independant shop. Dealer mechanics/shops seem to care less and cost more.

I wouldn't worry about a "valve job"....that term would imply the regrinding of valves and seats...and I highly doubt that will be necessary.

Get a valve adjustment done. Don't take offense if you know what this means...but assuming you don't... This refers to setting the clearance between the rotating camshaft and the top of the valve. To adjust this clearnce on each of the 16 valves there is a small round metal disc - a shim - on the top...they come in varying thicknesses. Unfortunately in the case of your CBR, camshafts have to be removed to access the shims....so....lots of disassembly. Take some measurements, more dissassembly if needed, swap shims (you'll pay for new ones, but if they offen give a partial value "trade in" on the old ones as they aren't a wear item)...then reassemble.

The cam chain tensioner, while a week point in the CBR, has no part in your low compression issue. If you have a noisey cam chain, you'll know it.

I've bought parts online a lot...even with shipping it saves money. oemcycle.com, westernhonda.com and so on...

Good luck,