Blowing Coolant!

[jackrb100]

I just rebuilt my motor and at the end of its 1st moto it blew coolant everywhere and emptied half the radiator. I checked the head for warping when building it but it was good, could the cylinder be warped? It appears to have been burning coolant also would this be down to cylinder warping? Does anybody have a list of possibilities for blowing coolant that I could just tick off as I troubleshoot.

[DnB_racing]

if you went big bore and used a regular bore head gasket, it will cause pressure to enter the coolant passages, or it could be just cheap poor sealing head gasket,

and yes it could be warped head, or cracked water jacket,

if you did go big bore and used a CW cylinder, they had some issues for a while with the water getting in between the water jacket and cylinder

more info on what was done when you built, and if there was any issues before would help

[maxamillion]

sounds like youre on the right track to finding the problem. yes the cylinder gasket surface could be warped. double check your radiator cap and make sure its holding the correct pressure. also make sure your torque wrench is calibrated so you get the right amount of torque on the head bolts.

[jackrb100]

The cylinder is standard. The engine heavily overheated in it's last moto last season(thermostat stuck) and this is it's first outing since then. That is why I checked the head for warping. I just didn't think the cylinder would warp rather than the head. Another question I have is weather it is ok to put these rings back into the new cylinder, they have only done about 1 hour? Thanks for the help.

[JessetheKid]

bad head gasket is possible, had this identical problem would put pressure on cooling sys and pour out overflow.

[fomospede]

i wouldnt use the rings
and i would replace the timing chain they dont like the heat at all

[jackrb100]

Ok so I've just checked the cylinder and head again and neither are warped!! I did notice that the intake port is lined with a dark green stuff, it is dry but is quite thick down near the valves. Anybody every see this before?

[fomospede]

pressur check the head its the only way to know if the head is cracked
talk to your local machine shop
if it got hot enough to crack the head
i would replace
the head
cylinder
and piston
and use a oem cylinder
they are the best
my .02

[jackrb100]

Has anybody ever seen the sludge in the intake port? Thanks for the help. I am going to probably change the head as I have a race this weekend and the cylinder, piston and timing chain are all new so they should be ok since the engine overheated last season before these parts were put in. Thanks again.