i did a top end job on my engine 16,000 miles ago with all new james gaskets due to a blown headgasket on my front jug. Last month the front headgasket blew out again. The dealer said the front head gasket blew out because the liner in the cylinder was comming loose. I replaced the cylinder with a good used one. A month later the rear cylinder headgasket blew out on the way home from alabama. I used all torque specs, every thing was clean and oiled. Any suggestions as to whats happening? I use mostly premium 91 octane and I don't hot rod it,but I do let the engine slow the bike down by downshifting alot. Do I have to look forward to this alot?
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The Bum
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Doesn't sound like you're doing anything wrong. I'd replace the rear with another used one. Possibly you just got hold of a bike that had bad jugs from the factory. Maybe some HD factory wrench, or the like will see this and clue you in whether that was a common problem or factory defect.
I like Jims gaskets, but had mine down so many times chasing a "ticking" I went back to cheap stock style and have had no problems. But with the head gaskets, I'm skittish about using a torque wrench to make the final twist. (per Jims instructions)The "degree method" is much more accurate from a mechanical point of engineering. I did mine by the book, then torqed them with a wrench to Jims specs. Most turned another 20 degrees or so. But again, I doubt that had anything to do with the liners giving up.
Doesn't sound like you're doing anything wrong. I'd replace the rear with another used one. Possibly you just got hold of a bike that had bad jugs from the factory. Maybe some HD factory wrench, or the like will see this and clue you in whether that was a common problem or factory defect.
I like Jims gaskets, but had mine down so many times chasing a "ticking" I went back to cheap stock style and have had no problems. But with the head gaskets, I'm skittish about using a torque wrench to make the final twist. (per Jims instructions)The "degree method" is much more accurate from a mechanical point of engineering. I did mine by the book, then torqed them with a wrench to Jims specs. Most turned another 20 degrees or so. But again, I doubt that had anything to do with the liners giving up.
As far as down shifting to slow your bike down. I have no idea if that could blow a gasket. I do know that it is hard on your bike motor and tranny. I would rather replace brake pads than rebuild a motor. Old school was to down shift and use the motor to slow you down, but keep in mind that the brakes back then sucked and would fade. Drum brakes. There is no need to do this today. Save your motor.
As far as the torque on the HD Evo and newer. The Evo motors are modeled by airplane motors and the head torquecalledis simular to a airplane motor( light weight ) due to being made out of aluminum and not cast steel like the Shovels and older HDs.
When I first torqued a Evo head I could not believe the torque instructions as it was not something I was use to. I called HD to get the facts and this is what I was told. Torque like a airplane motor.
One more thing before torquing the Evo head make sure that the nuts turn freely or lightly lubricat them in order to get the proper torque before the final turn.
They had some problems with the twin cam cylinders liners moving, but I never heard of evo's doing it. we've had two evo's in with blown head gaskets this year, both had the stock gaskets without the metal ring around the inside and were torqued right. I am begining to believe that maybe the 10% ethanol has something to do with it. We are putting in copper or MLS gaskets in all our engines now in hopes of alievating any future problems. I will keep everyone posted on the situation if it continues. I suppose we could hav gotten some inferior gas in the area, lets hope that that is the problem.
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John Therrien
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I think if you read the service manual it recommends no lube on the head bolts and the proper torque is the "torque to yield" method. Road an evo for 10 years never heard of one liner coming loose. James gaskets are decent. Built a stroker with stock cylinders bored out and James gaskets. No problems. Used the HD service manual for headbolts torque.
They had some problems with the twin cam cylinders liners moving, but I never heard of evo's doing it. we've had two evo's in with blown head gaskets this year, both had the stock gaskets without the metal ring around the inside and were torqued right. I am begining to believe that maybe the 10% ethanol has something to do with it. We are putting in copper or MLS gaskets in all our engines now in hopes of alievating any future problems. I will keep everyone posted on the situation if it continues. I suppose we could hav gotten some inferior gas in the area, lets hope that that is the problem.
You are probably right about the lube, mine were so hard to turn that I was afraid that my torque would be off. Basicly what I did was to lube very lightly and wipe it off, so that the bolts turned freely without much drag.
What exactly is Ethenal that is sometimes added to gas?
Does Ethenal burn better or worse than gas?
blown headgasket
