Hi i brought a 1989 h1 zxr 400 as a project I have don't most of the work to it there is just a few problems. My engine has stared to over heat to much, the temp gauge just starts to shoot to the red mark after its warmed up to temp you give it 1 min max n it will go to the red mark. some one said I had a dodgy rad cap so i brought a brand new one but has not helped i have a 10 min ride n when i get off the bike i look at the expansion chamber n its past the full mark it right to the brim some times pisses out the expansion chamber breather pipe only really happens in the day when its hotter why is that ? & i changed the coolant i looked in the manual n it says 2.3l but i can only fill it to 1.8l i taped the hose to get the air but could only get 1.8l in n no more why is that ? last thing is my friend had a cbr 400 and he went on my bike and said that's no way near as fast a his cbr n the zxr 400 are meant to **** on the he thinks its restricted if so where could it be where should i check it looks like there are some restricters on the exhaust manifold or they just a metal gasket looks like to plates please help thanks you

 

Welcome to KF

You mentioned coolant coming from the expansion chamber? That generally indicates that you have a head gasket issue which will cause the overheating and the coolant leak. Pull the plugs and inspect. If you have a leak down tester, then you can also check for leaks that way. Maybe if you can keep the compression, your buddy would not say too much bad concerning your ride.

 

Agree with Drag^ on the head gasket, based on your description. Seriously, do NOT get your bike way hot or you'll have even more problems to fix. (Don't continue to ride it just because "it still runs.") .....and leave the thermostat in place; there's a good reason why it's there. As suggested^ look at your plugs, oil (see any milk?), and inspect around the head/jugs for leaks you haven't noticed previously. Does your rad fan work?