www.zxrworld.co.uk

Hi there,
Attention aspiring/seasoned diagnosticians,
Our ZXR 400 H is overheating after 10 mins of regular road riding.
Have flushed cooling system with clean water.
Have replaced thermostat and radiator cap.
Plastic overflow bottle fills up with boiling water and overflows after 10 min.
Motor runs sweetly, good power,
Good Compression @ 120 psi even across cylinders.
Fan works fine.
We are using appropriate coolant also.

Thankyou for any suggestions.

have you checked for head gasket sysmptoms?

Hi,

I have a feeling you might have a pipe blockage somewere or the pipes are restriced with crud causing the water not to flow around the bike properly.

Or....... your water pump is shagged.

Hope this helps.

Regards

Rich

Thanks for replies,
Yea we have a new head gasket on its way, we aren't sure if there is anything wrong with current one though. Just be a pity to pull it to bits unnecessarily. Might have to look into the water pump idea also.

99% itll be headgasket im afraid. if its overflowing while reading cold on the gauge still then thats the problem.

sounds like its gone on the exhaust side and the heat is boiling the water and pressurising the system hence it spewing out of the expansion box asap.

itll be the engine pressurising the cooling system for sure by the sounds of it.

Just pulled the head off and it looks like the gasket is blown between a cylinder and the water jacket.So that has got to be the problem. Just waiting for new one now .