1999 CBR 600 F4

With the bike at idle in the driveway after 20minsthe temp guage is 3/4 to the H. It is 95F here in Portland today. No coolant leak. The overflow container is at the high line. Here is what I did just before:

- Replaced the stock air filter with a K&N.
- Checked the plugs (clean with a slight tinge of pink on the insulator)
- Put her all back together

After I put her all back together and took her for a ride, she started spurting coolant all over the place. The radiator cap wasn't sealed on tight. SO, I replaced the radiator cap, and gently pried out the lip on the part of the radiator that the cap goes on. Somehow that had gotten pushed in enough that the radiator cap could slip off. I refilled the radiator and bled it as per the shop manual.

So far I've:
- Checked the oil level (right at the top line)
- Replaced the radiator cap
- flushed the coolant system

In case you might be thinking that 3/4 isn't so bad, it does overheat when I go for rides.

 

You're either running real lean or you still have air in the system. If the rad cap is opposite of kickstand, then lean bike and open rad cap when cold. Start bike and and blip the throttle a few times. Now squeeze every rad hose working towards the flow of the pump (if you know which direction). Blip the throttle a few times again. If the coolant goes down in the rad, then add some more and repeat process till it doesnt go down.

 

i agree^ probably air in the coolant lines. make sure the bike is running when u fill it up.

 

Ok, I'll try again to bleed the system. I went for a ride again tonight after running through to process again, and putting the bike back together, and it ran at a fairly normal temp (between half way and 2/3). This is when the temp was back down to 73 and there was not much sitting in traffic. I'll see if I can manage to get some more air out.

Can we speculate on the running lean possibility? Here is the thing; I don't know if the previous owner rejetted the bike or not, and he put a Yosh RS-3 slipon on the bike. Just today I replaced the stock filter with a K&N. My question is, if the bike was running really lean and causing the excess heat, wouldn't there also be flat spots going through the power band, and other problems? The bike runs really clean through the power band on all gears with no hesitations. The only thing I notice at idle is that after the bike gets up to temp the idle is uneven. It bounces between 1250 and 1500. The mechanic I talked to seemed to think it was normal, or that maybe I could adjust the pilot screws.

 

I'm gonna go with no on the idle. Usually you dont have to rejet with a slip on, but mess with anything on the intake and you usually do. Is it a stock replacement type K&N or K&N pods?


If you want to see if you're running lean, then get on non busy highway. Start the engine and take off, dont let it idle. Get up to 70mph (or what ever the speed limit is) at above mid rpm to high rpm (3rd or 4th gear) and hold it there for a minute or so. Then clutch and kill the engine, again dont let it idle. Hold the clutch and just coast to a stop. Pull the spark plugs and see what color they are. Pics would be great.

 

Ok, I'll have to wait a couple of days to do that, because I'm moving. The filter is just a K&N OEM replacement (not the pods). It didn't look like the stock filter had ever been replaced and it was REALLY dirty, so I went from a dirty OEM to a higher flowing K&N. I hate pulling the plugs! So much work on the side of a highway. On my ninja 250R I only had to pull the tank to get to the plugs. Oh well.

BTW, the replacement filter I got was only 13psi and the stock is rated for 16... i.e., do not get STANT 11227 replacement. Instead the STANT 11233 is the one to go with. I wish there was an 18psi version since that's right in the middle of what the shop manual range is.

 

And what are the plugs suppost to look like?

 

http://www.verrill.com/moto/sellingg...colorchart.htm

 

Also a K&N filter doesnt do its best till its a little bit dirty. And you dont have to pull the tank on a 250 to get the spark plugs out. I know.

 

3/4 to H should still be in op range. I fail to see the problem. Its summer. Everyones bike is running hot. On average, going 65 mph during summer and my bikes runs at about 210 Deg F. During night or when the weather is below 85 Deg F my bike runs at about 180 Deg F.

When I sit in traffic in 90+ deg weather my bike hits almost 235 deg. Overheating is 251 deg.