Hello all,
I picked up a 1996 CBR 1000F about a month ago and am having some serious cooling issues. When I put water in the bike and run over about 5000 RPM's for hardly any time at all the cooling system is building a lot of pressure and pushing all of my coolant out of my reservoir... There are no leaks in the system as I have repaired them all and have also put on a new radiator cap and thermostat. I also straight wired the fan in order to ensure it was running. I have spoke to many shops as well as mechanics and no one can give me a straight answer... Blockage or blown/ leaking head gasket. Which is it?
Thanks in advanced,

 

Did you replace the anti freeze/anti boil, believe me this can make a huge difference, without it, the water boils easily & can cause the pressure you're talking about.
You can have you're radiator pressure checked at the shop, this should pick up if there are any blockages. You can also get some pretty good products that will clean & descale the innards of the radiator. As for a blown head gasket, look for the signs, water in the oil, coolant level dropping quickly, brown crud at the back of the exhaust etc. I've had my bike for 12 years & apart from when I change the coolant, never had to top it up.

 

My initial guess would be bad head gasket, cracked head, cracked cylinder wall. It sounds like your dumping compression into the cooling system.

The only reason I say this is because its rpm induced. Your rpms increase, it pumps more compression into the cooling system, and you get the overflow.

Does the anti-freeze smell odd? many times, it will smell kind of like exhaust, since your basically dumping exhaust into the system.

as for a straight answer as to what it might be, its very hard to say 100 percent over the internet. Even a shop will have to do some testing to properly diagnosis the issue.

 

Antifreeze boils out just like water... I have tried water wetter as well to keep the bike cooler... I will certainly have the pressure checked before I dive off into the other stuff

 

I think this is whats going on. If I replace the head gasket how necessary is it to have the head machined before putting everything back together?

 

QUOTE]I think this is whats going on. If I replace the head gasket how necessary is it to have the head machined before putting everything back together? [/quote]

If you find out its just the head gasket, I would at least have the head surface checked. it also depends on where the failure is. If its around one of the water jackets, it could have eroded the mating surface of the head and the block. If its around the cylinder wall, theres a good chance the head is warped allowing the compression to go by.

However, for the symptons you meantioned, I'd really be looking into the cylinder wall for a crack. A head gasket or warped head will usually be slowly build up pressure and then overflow... a cracked cylinder will usually be rpm induced.

Its hard to say what happened, as the previous owner could have done anything to it. Normally, over heating will cause a bad headgasket or warped head. A cracked cylinder usually happens from the coolant freezing, but can also be from overheating.

Do you know the history of bike?, such as if it was overheated or not winterized?

But, its always a good idea to at least have things checked. If it looks like the head gasket, have the head checked for straightness and maybe magnafluxed to make sure there aren't any cracks.

oops, I don't know if you can magnaflux an aluminum head... I don't think it can be done. I think they can pressure check it though.

Any machine shop should be able to do these things.

 

Another thought, might be a long shot, but cheap and worth looking into. Make sure the radiator cap is good.

edit: nevermind.. I see you already did this... sorry,

 

Replace all the coolant with the correct anti-freeze, and fill to the right level.
If it's still pushing it out, probably a blockage or head gasket.
Check all your connections, especially the 3 way plastic hose connector near the radiator - they fail after time, and can cause major coolant loss if you've developed a crack.......
try the cheap stuff first.........
And I've moved this post to the Hurricane section - you'll get more response there....

 

Well with a new cap and fitted and thermo then it would appear to me the head gasket
is gone if she's shoving the coolant out through the resevoir as the rpm goes up.

But cheap option is to completely flush her with new coolant and see if it still does it.

Do you think the motor was run "dry" "HOT" before you got it ?? if so the head will
absolutely need to come off....... also check that triple joint like Shadow says that
may have been the initial culprit before she got cooked. I think you are looking at the
after effects of overheating somehow.

 

Hi guys

I had a similar problem and was able to solve it this week, it started when I replaced the O ring of the main hoses junction under the tank, pressure was building up and it was spewing antefreeze out as soon as the motor was warm. Well I sat down and checked the plumbing , solution is so simple, in the reservoir the over flow hose was to long, it was touching the bottom of the reservoir so as soon as the bike was sending antifreeze in the reservoir with the pressure, the overflow hose was discarding it because it was as the reservoir was too full even though I filled it to the top mark, solution: I cut the overflow hose in side the reservoir halfway so that way if the coolant really goes above the mark it will then send it out trough the overflow hose.

Voila no more problem, it was simple fix, but you had to think about it!