Head Gasket Questions - OEM with Overbore & Coolant Leak
Posted: July 2nd, 2013, 10:30 am
Hey guys - Couple of questions on head gaskets and to possibly rootcause a leak.
Combo: 2000 CR500 / '89 Motor / '86 style HF-1 head / 1.5mm Over
Running a Cometic 85-88 (thicker) head gasket to get compression down with HF-1 head and pump gas. Started up the bike and I'm leaking out of the front of the head. Actually most of the coolant is bubbling up through the stud/nuts on at least 3 of the forward studs. It was hard to tell if the leak was actually coming from the gasket area or just dripping down from the studs. I did not use gasket sealer and did not check head for flatness (although head was re-installed as-is and didn't leak before)
I re-checked torque and they were good. Gave them about an extra ¼ turn. This improved the seal but still seeing little bubbles coming up the forward couple of studs.
I’ve ordered Honda gasket P/N 12254-ML3-881 which is the 3 layer for ‘85-‘88. However I’m not sure I can use this with a 90.5mm bore – Can anyone confirm? Without removing the gasket from the package it looks like the ID is about 90.2mm.
If I can’t run this OEM gasket due to my bore size, can anyone recommend a good one? With or without sealer?
I have not taken it back apart yet to check, but I suppose if the head measures more than 0.002” out for flatness I’ll need to work it in with some light sand paper on a granite plate?
Thanks,
Scott
Combo: 2000 CR500 / '89 Motor / '86 style HF-1 head / 1.5mm Over
Running a Cometic 85-88 (thicker) head gasket to get compression down with HF-1 head and pump gas. Started up the bike and I'm leaking out of the front of the head. Actually most of the coolant is bubbling up through the stud/nuts on at least 3 of the forward studs. It was hard to tell if the leak was actually coming from the gasket area or just dripping down from the studs. I did not use gasket sealer and did not check head for flatness (although head was re-installed as-is and didn't leak before)
I re-checked torque and they were good. Gave them about an extra ¼ turn. This improved the seal but still seeing little bubbles coming up the forward couple of studs.
I’ve ordered Honda gasket P/N 12254-ML3-881 which is the 3 layer for ‘85-‘88. However I’m not sure I can use this with a 90.5mm bore – Can anyone confirm? Without removing the gasket from the package it looks like the ID is about 90.2mm.
If I can’t run this OEM gasket due to my bore size, can anyone recommend a good one? With or without sealer?
I have not taken it back apart yet to check, but I suppose if the head measures more than 0.002” out for flatness I’ll need to work it in with some light sand paper on a granite plate?
Thanks,
Scott