Cooling Problem (Yamaha LC350)

[feelergaugephil]

Yes I know it's the Blackbird site, but I know there is folk on here that might own the above bike.
My friend has a fully restored one, and he has dropped it off over at my place to fix, it ran fine before it was restored, he replaced 90% of engine parts and it is in showroom condition.
It's a 1996 F2 model, He replaced the head with a billet racing head, it runs fine up till getting warm, then it makes a whinning noise then it begins to push water into his expansion bottle the the needle goes into the red, he then cuts it off then.
Any ideas? I have the original head (YPVS) which I might put back on to see if this is the problem!!

 

[RHINO]

Sorry, not much use to ya but........ If i can find a nice blue and white 1981/82 model then i'm inthe market, would also consider a 250 version.

 

[feelergaugephil]

water pump not circulating water

mixture too weak
stat not opening

billet head not drilled for cooling properly.

If old heads are refitted and problem goes, it is the head, but check the other stuff too. Check for air locks too.

I believe you may be correct on the drilling of head, water pump is working properly.

 

[solorider]

have you any antifreeze in the system? if no then as soon as the water hits just below 100 deg c then it will boil and do what you say

 

[DB on CBR1100XX]

Hmmmmmmm.....

have you any antifreeze in the system? if no then as soon as the water hits just below 100 deg c then it will boil and do what you say

.......but it's a pressurised system and that means the water shouldn't boil @ 100 deg - so you may have a leaking rad cap - the water can only get to the expansion bott after blowing past the rad filler cap............... l4m3r

 

[FIREJIM5]

re

check the water pump drive,if memory serves me the little plastic worm gear is known to shear.
Jim.

 

[Coggy]

Cylinder head leak?

sh1tehppns