having coolant problems

[924dr]

i need some help with this i cant figure it out. my cousin jus had his shee built with the vitos big bore kit in the stock cylinders with a hemi head an 24cc domes the issue is the coolant will spray out the overflow vent tube so we block the over flow on the rad. an no sooner did we did that he rode it for maybe 10 mins then it blew the line of the top of the head

 

 

so what would that be any help will be awesome thanks

 

justin

[tedd1]

Pull the head back off and check the o rings at domes. Prob'ly pinched one.

[924dr]

We checked the dome gaskets they looked good not smashed or anything

 

Anything else come to mind

[crustydemon]

Sounds like a blockage somewhere not letting the coolant circulate then building pressure when it gets hot.

[texasbanshee]

A lean A/F ratio can cause it to run hotter.

 

Don't know what your combo was before, did it change significantly during the new build? Were the cylinders ported after the big bore sleeves were installed?

[924dr]

it has an oversized rad in it a brand new water impellar i will have to have my cousin get on here to give the details on the porting i think

 

it all started when he pulled it out of the back of his truck an it sat up right (front wheels in the air an it resting on the rear wheels an grab bar) from then on it sprays out the coolant from the resivor vent tube

 

as far as an air bubble i think he checked for it but i will double check or have him post up on here

 

thanks for all the ideas so far

justin