Compression tests
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Outstanding HDF Member
Joined: May 2008
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From: Mount Holly, NC
heres the thing: the engine is stock. i knew i'd be putting a lot of miles on the bike and didn't want to make any changes in case of a warranty issue. i figure they designed it to run a certain way and messing with the design is asking for trouble. plus, if the moco has a design-fault, they'll catch it. or, if the bike is a statistical fatality because of stringent epa regulations, they'll document these cases and use them to combat stupid regulation.... i hope.
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From: New Port Richey FL
any word from your dealership or wherever ya took it?
i'm very interested because i have an 04 1200c with almost the same miles and have noticed some white smoke outta the front exhaust pipe on decel and down shift...haven't had time to do a compression test yet (i just make sure there is oil in her and keep riddin) but she is most deffinetly burnin oil
i hope its just valve seals but i'm not holdin my breath
i'm very interested because i have an 04 1200c with almost the same miles and have noticed some white smoke outta the front exhaust pipe on decel and down shift...haven't had time to do a compression test yet (i just make sure there is oil in her and keep riddin) but she is most deffinetly burnin oil
i hope its just valve seals but i'm not holdin my breath
Club Member
Joined: Feb 2007
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From: Boynton Beach, FloriDuh
any word from your dealership or wherever ya took it?
i'm very interested because i have an 04 1200c with almost the same miles and have noticed some white smoke outta the front exhaust pipe on decel and down shift...haven't had time to do a compression test yet (i just make sure there is oil in her and keep riddin) but she is most deffinetly burnin oil
i hope its just valve seals but i'm not holdin my breath
i'm very interested because i have an 04 1200c with almost the same miles and have noticed some white smoke outta the front exhaust pipe on decel and down shift...haven't had time to do a compression test yet (i just make sure there is oil in her and keep riddin) but she is most deffinetly burnin oil
i hope its just valve seals but i'm not holdin my breath
Ultimate HDF Member
Joined: Sep 2005
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From: Ozark Country
Yep, when my Harley mechanic friend swapped in the Screamin' Eagle "E" cams on my 2005 1200C he also changed out the valve seals.
He said that in my case they appeared to be fine, but he wanted to replace them before any problem might develop.....
He said that in my case they appeared to be fine, but he wanted to replace them before any problem might develop.....
Outstanding HDF Member
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From: New Port Richey FL
Grand HDF Member
Joined: Sep 2007
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From: Boise Idaho
Your vibration is probably a motor mount or some other miner thing.
If I was a mechanic in a shop I'd be smiling everytime I had someone walk in with a self diagnosis.
Last edited by jag1886; Nov 5, 2009 at 06:15 PM.
Thread Starter
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Outstanding HDF Member
Joined: May 2008
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From: Mount Holly, NC
the moco's testing methodology is just a wee tad different than yours. but hey, i hope the bike is fine cause i need both bikes to be road worthy next weekend.
Outstanding HDF Member
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From: New Port Richey FL
hey what kinda sporty ya got? (year/model) do you have engine work done?
i checked my book today for my 04 1200c and it said the psi on the compression test should rread 120...your first post said double that....whats the deal?
i checked my book today for my 04 1200c and it said the psi on the compression test should rread 120...your first post said double that....whats the deal?
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Outstanding HDF Member
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From: Mount Holly, NC
its an 08 nightster. says the compression should be between 200 and 225 psi dry. no engine mods. i'm too lazy to scan the page and post it. someone else might open their manual and confirm. page 3.11
it says the difference should not be more than 10 psi between cylinders.
it says lower than 150 is a problem. it also says there should be no significant change in compression when oil is added.
i'll accept that the rings are not completely shot. however, the big jump in wet compression seems excessive for an engine with so few miles. sorry if i offend anyones sensitivities but 42k is nothing.
it says the difference should not be more than 10 psi between cylinders.
it says lower than 150 is a problem. it also says there should be no significant change in compression when oil is added.
i'll accept that the rings are not completely shot. however, the big jump in wet compression seems excessive for an engine with so few miles. sorry if i offend anyones sensitivities but 42k is nothing.
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From: Boynton Beach, FloriDuh
883cc - 125-140 psi
1200cc- 200-225 psi