High compression engine failure
Tourer
Joined: Sep 2014
Posts: 420
Likes: 5
From: Kingsport, TN
Not outrageous, but aggressive (especially the 9.8:1 corrected CR), and will likely make your motor and its longevity sensitive to optimized tuning, fuel quality, ambient temps, and control of combustion temperature as ambient temps rise in the coming months of summer, as well as starter/battery challenges. Plan to address these issues, IMHO.
Last edited by dynawg1; May 13, 2015 at 07:28 PM.
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Road Warrior
Joined: Mar 2009
Posts: 1,485
Likes: 232
From: Ohio
Not outrageous, but aggressive (especially the 9.8:1 corrected CR), and will likely make your motor and its longevity sensitive to optimized tuning, fuel quality, ambient temps, and control of combustion temperature as ambient temps rise in the coming months of summer, as well as starter/battery challenges. Plan to address these issues, IMHO.
HDF Community Team
Joined: Jun 2006
Posts: 12,782
Likes: 2,610
From: san antonio
As I said in my previous, mock the motor up and measure everything; measure twice. If everything fits up properly, put it together and fire it up. Don't worry about compression, stick with the .030" head gasket, you have plenty of compression for the 6-6 cams. Check CCP when you get it put together; you can do that before you fire up the motor. The quick starter bursts will help the oil to start moving. Don't heat cycle the crap out of the motor; two heat cycles, 30-60 seconds each is enough to hear any funny noises and look for any leaks. If no weird noise, no leaks, jump on for a quick run around the block. No weird noise, no leaks, take a ride and seat the rings. No synthetic oil, something like Shell Rotella 15W40 which you will drain out and change filter at about 100 miles.
Good luck! Let us know how it goes.
Tourer
Joined: Jul 2007
Posts: 497
Likes: 8
From: New Egypt, NJ
"A little pinging" could be the cause of your crankpin failure, though I would think the pistons (or a piston) would be hurt as well. But the nature of pinging is that you don't hear most of It. What you do hear means it's been happening but you haven't heard it until now.
Tourer
Joined: Jul 2007
Posts: 497
Likes: 8
From: New Egypt, NJ
"A little pinging" could be the cause of your crankpin failure, though I would think the pistons (or a piston) would be hurt as well. But the nature of pinging is that you don't hear most of It. What you do hear means it's been happening but you haven't heard it until now. Just speculation on my part, but pinging isn't something to take lightly.
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Road Warrior
Joined: Mar 2009
Posts: 1,485
Likes: 232
From: Ohio
Final follow up. When I went to the dealership for parts, I told the parts guy what I finally found. He asked the mechanic about possible causes and he said only 2 possibilities. One is material defect which I ruled out with a metallurgy report. The other is lack of lubrication. I know last year while chasing this noise, I found my oil pump gouged and replaced it. I still had good oil pressure but maybe I had reduced flow. I don't know.
Anyhow got it back together and it runs fine. I went back in with the stock 0.046" head gasket which has lowered my compression ratio and reduced my power. Bike feels smoother but not as crisp or responsive as it did. It sounds good and I hope it will last more than 40k. Thanks to all who gave their opinion. Much appreciated.
Anyhow got it back together and it runs fine. I went back in with the stock 0.046" head gasket which has lowered my compression ratio and reduced my power. Bike feels smoother but not as crisp or responsive as it did. It sounds good and I hope it will last more than 40k. Thanks to all who gave their opinion. Much appreciated.
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HDF Community Team
Joined: Jun 2006
Posts: 12,782
Likes: 2,610
From: san antonio
Final follow up. When I went to the dealership for parts, I told the parts guy what I finally found. He asked the mechanic about possible causes and he said only 2 possibilities. One is material defect which I ruled out with a metallurgy report. The other is lack of lubrication. I know last year while chasing this noise, I found my oil pump gouged and replaced it. I still had good oil pressure but maybe I had reduced flow. I don't know.
Anyhow got it back together and it runs fine. I went back in with the stock 0.046" head gasket which has lowered my compression ratio and reduced my power. Bike feels smoother but not as crisp or responsive as it did. It sounds good and I hope it will last more than 40k. Thanks to all who gave their opinion. Much appreciated.
Anyhow got it back together and it runs fine. I went back in with the stock 0.046" head gasket which has lowered my compression ratio and reduced my power. Bike feels smoother but not as crisp or responsive as it did. It sounds good and I hope it will last more than 40k. Thanks to all who gave their opinion. Much appreciated.
Last edited by djl; May 27, 2015 at 12:42 PM.
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