New top end is leaking coolant????

[DGMCR250]

In re-doing my top end I asked if I needed to use a gasket sealer for the head and cylinder gasket and two people said to just throw them on dry. Well, now everything is put together and during break in there was a lot of coolant leaking. Do I just need to tighten the head and cylinder bolts more or do I need to tear it all down and use gasket sealer on those two gaskets? By the way I didn't use a torque wrench on the cylinder and head bolts so I don't know if they are tight enough :bang: , although they seemed to be tight enough. Any help would be appreciated....

 

[plumma]

I just rebuilt my top end on my bike (02 CR125) and I torqued down all cylinder bolts to spec. I would highly recommend torquing them to spec if you can get the specs. Another thing, did you get all new gaskets for the rebuild? if not that may be your problem also.. never reuse gaskets unless they are made to be reused..

 

[DGMCR250]

ya, I used new gaskets but you're right i do need to check the torque specs. It should be easy to torque the head bolts but the cylinder bolts are hard to get with a torque wrench. Will it damage the cylinder if coolant is leaking inside the cylinder and how can I tell if it is leaking inside the cylinder?

 

[nickyd]

did you put the head gasket bump side up? some are happier being put on in that direction.

 

[plumma]

ya, I used new gaskets but you're right i do need to check the torque specs. It should be easy to torque the head bolts but the cylinder bolts are hard to get with a torque wrench. Will it damage the cylinder if coolant is leaking inside the cylinder and how can I tell if it is leaking inside the cylinder?

if your coolant is leaking inside the cylinder than probably your trans oil will be like a milkshake.

 

[DGMCR250]

i don't remember, but I did tighten the head bolts slightly and that stopped the leak at the head but I also slightly tightened the cylinder bolts and it still has a very slight leak at the cylinder base.

 

[DGMCR250]

if your coolant is leaking inside the cylinder than probably your trans oil will be like a milkshake.

would that be the case on a two stroke? isn't the tranny oil completly seperate from the cylinder. with the motor running it appeared that my exhaust was more wet (not spoogy) so I assumed that some coolant was getting inside the cylinder.

 

[viking20]

You need a torque wrench for this kind of job.....
The trans oil wont be mixed with coolant , the cylinder/crankcase is separated from the gearbox...
Worst thing that can happen , if you get coolant in the combustion chamber , is a piston failure.
The coolant cools the very hot piston crown , and the edge of the cylinder and head , the aluminum breaks off in small pieces because of this.
Even a few minutes of riding can destroy the mating surfaces of cylinder and head , and if the piston fails , it can easily cost you a cylinder/crank.
Check it out before riding the bike again....
And its not nessecary to use a sealant on the gasket(s)