I’m at a bit of a loss and hoping this group can help me!
Had a coolant leak issue last fall that I traced to a blown head gasket. Installed new head and base gasket along with new piston. I also sanded the head and cylinder flat/ clean prior to re-installation (pic below)
This on a CRF that has separate oil for engine and trans
My problem - Took bike out for 1st ride today and oil is all milky/ greenish looking (see photo on right). Engine oil level was also rising. I use blue colored coolant
Could my head be cracked? Is there a way to check this at home?
Would trans oil coming into engine oil cause this?
Radiator level was maybe down 1/4” from when started. Hard to tell as I only rode ~15 min and decided best to stop before causing further issues.
Head gasket issue in the fall didn’t result in any coolant in the oil. It all went outside the cylinder via a leak right below exhaust flange. I did have a minor over heat incident though as didn’t realize coolant was out.
I did do a check via pressurized radiator cap and that held pressure for more than 24 hours. I suspect my issue is very minute and thus coolant isn’t leaking unless under significant load/ heat.
Thanks!
Most likely causes are bad water pump seal (oil side) and head gasket. Looks like you have the head off so you will have to replace that. Do you have water leaking from the weep hole under the water pump? Is the hole plugged? If you replace water pump, replace both seals and impeller shaft. Was the reason you resurfaced the head because it was warped? Check for warping by placing head on flat surface like plate glass and check with feeler gauge. Specs in service manual. Good luck.
My understanding is that with separate trans and engine oil there isn’t a way for coolant to leak past the water pump into engine oil. It can leak into trans but not engine oil. I could be wrong on this.
Head was off… I had a bad head gasket last fall. I sanded it to clean it up and ensure it was flat. New head gasket has 15 min on it so seems unlikely that is the cause of it the leaking.
Did you surface the head or sand it. Hearing you say "sanded" it makes my butt pucker.
I surfaced the head using a granite plate with sandpaper attached. Just like they would do at fastheads
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Anyone have any experience with this?
Laminated metal head gaskets have a pretty strict requirement for surface smoothness in order to work correctly. Basically the RA has to be low, like 30-50RA for them to seal properly. Likely finer than what you achieved with sandpaper. Do some googling on laminated metal head gaskets and surface RA. Not saying this is the cause of your problem, but something to look into and consider.
Helpful.... do you think the surface being too smooth could be an issue? I finished the head and cylinder with 1000 grit which is supposed to correspond to 10RA. 50RA = 320 grit. I started out with 600 and then finished off with 1000.
In the case of surfaces not proper RA would you expect coolant to leak into the combustion chamber as I'm NOT seeing this?
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