The Autonerdz Community Forums - in cyl compression

TrevorSchlientz Autonerdz Administrator Picogroup Offline I'm an Autonerd Posts: 1,403 Grand Rapids Michigan USA Gender:	Re: in cyl compression - thoughts Reply #15 - Jan 23^rd, 2024 at 7:18am I considered taking a side gig at a local powersports dealer before. I wondered if that would be a decent change of pace from the auto side.
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James H Senior Member Picogroup Offline Bike Nerd Posts: 165 Waterloo Ontario Canada Gender:	Re: in cyl compression - Issue found Reply #16 - Jan 23^rd, 2024 at 9:06am So, for those interested it was a badly worn exhaust rocker and cam lobe. See attached picture. Piston and cylinder are in reasonable shape. Head needs intake valves and the seats need to be cut.
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StitchB

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Re: in cyl compression - thoughts
Reply #17 - Jan 23^rd, 2024 at 9:59am

James, so glad to hear. And being a neophyte at compression wave forms, I feel good I was in the ball park. But I do think Trevor brought up a thought that I never would have. That was some serious wear but I think the capture headed you in the right direction. Over time if WE, see enough captures like Harley Mike, we can almost 95% of the time hit it pretty close. This is really nice for the customer before he spends a bundle on guess work.
For me as they say, even a blind squirrel finds a nut once in a while.

Hope shop is doing well and keep posting, all solid stuff.

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StitchB

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Re: in cyl compression - thoughts
Reply #18 - Jan 23^rd, 2024 at 10:07am

TrevorSchlientz wrote on Jan 23^rd, 2024 at 7:18am:

I considered taking a side gig at a local powersports dealer before. I wondered if that would be a decent change of pace from the auto side.

Trevor, I think you would enjoy it, and I guarantee you they are looking at this stuff with nothing but a scanner, and even that probably not very well. JMO.

Or at least offer to look at one of their problem childs, get a feel. James here is at the top of his game but didn't come from the auto side so the learning curve is steeper for him. I notice not a lot of feed back so he is shooting in the dark.

I was helping a guy on 2012 BMW GS few months back, 02 sensor, MAP all of it as pretty much a Bosch system, and everything a guessing game and you need a BMW Scanner. But with a scope you are now coming from a different angle. JMO.

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Intermittent Junior Member Picogroup Offline I'm a Dieselnerd Posts: 52 Spring, TX Texas USA	Re: in cyl compression - thoughts Reply #19 - Jan 23^rd, 2024 at 10:43am Thanks for the update James. This was an interesting one. I shoot a lot in the dark on medium and heavy duty diesels. Larry, has been helping me as well. Really a great mentor who is not afraid to help. Hopefully we can get an after capture.
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TrevorSchlientz Autonerdz Administrator Picogroup Offline I'm an Autonerd Posts: 1,403 Grand Rapids Michigan USA Gender:	Re: in cyl compression - thoughts Reply #20 - Jan 23^rd, 2024 at 10:50am Intermittent wrote on Jan 23^rd, 2024 at 10:43am: Hopefully we can get an after capture. +1
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fisher Super Nerd Picogroup Offline Deceased Posts: 2,734 Concord California USA Gender:	Re: in cyl compression - thoughts Reply #21 - Jan 23^rd, 2024 at 1:37pm It seems anytime we see a compression waveform that doesn't look like the classic form it is going to be time to learn why by taking things apart.
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StitchB

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Re: in cyl compression - thoughts
Reply #22 - Jan 24^th, 2024 at 12:03am

fisher wrote on Jan 23^rd, 2024 at 1:37pm:

It seems anytime we see a compression waveform that doesn't look like the classic form it is going to be time to learn why by taking things apart.

The upside, for in this case James, he tells the customer going in, we know we have valve train issue, do you want to pull the trigger and move forward? The wear on that cam is massive, a better question is what caused it?

And the capture will just be one more piece of history to use later on. James is a serious player, last I talked had a dyno, trying to raise the ATV world up to another level, hope he gives us an after capture.

Larry

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TrevorSchlientz

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Re: in cyl compression - thoughts
Reply #23 - Jan 24^th, 2024 at 3:50am

StitchB wrote on Jan 24^th, 2024 at 12:03am:

The wear on that cam is massive, a better question is what caused it?

My theory is valve clearances too tight. The valve and seats wear down and then there is constant tension on the cam and rocker pad and no clearance for oil. It my experience machines like this are easily neglected for oil changes too so you get a year or more of degradation combined with tight vales and this is the result I would expect.

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HarleyMike

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Re: in cyl compression - thoughts
Reply #24 - Jan 24^th, 2024 at 5:31am

TrevorSchlientz wrote on Jan 24^th, 2024 at 3:50am:

It my experience machines like this are easily neglected for oil changes too so you get a year or more of degradation combined with tight vales and this is the result I would expect.

Just to add to that, most people just flat out run the piss out of them along with the neglect.

Thanks for the follow up!!

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James H Senior Member Picogroup Offline Bike Nerd Posts: 165 Waterloo Ontario Canada Gender:	Re: in cyl compression - thoughts Reply #25 - Jan 24^th, 2024 at 6:51am The sad thing is it is owned by a mechanic!!
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StitchB Super Nerd Picogroup Offline Posts: 1,314 lake stevens Washington USA Gender:	Re: in cyl compression - thoughts Reply #26 - Jan 24^th, 2024 at 10:38am James H wrote on Jan 24^th, 2024 at 6:51am: The sad thing is it is owned by a mechanic!! Now that is funny. If a mechanic why are you working on it. Tight lifters. Back in the day my dad used to say about loud lifter. If you can hear them they aren't burning. A little different today but clearance is your friend.
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StitchB

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Re: in cyl compression - thoughts
Reply #27 - Jan 24^th, 2024 at 10:39am

HarleyMike wrote on Jan 24^th, 2024 at 5:31am:

TrevorSchlientz wrote on Jan 24^th, 2024 at 3:50am:

It my experience machines like this are easily neglected for oil changes too so you get a year or more of degradation combined with tight vales and this is the result I would expect.

Just to add to that, most people just flat out run the piss out of them along with the neglect.

Thanks for the follow up!!

The term rode hard and put away wet would apply. JMO.

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StitchB

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Re: in cyl compression - thoughts
Reply #28 - Jan 24^th, 2024 at 10:41am

TrevorSchlientz wrote on Jan 24^th, 2024 at 3:50am:

StitchB wrote on Jan 24^th, 2024 at 12:03am:

The wear on that cam is massive, a better question is what caused it?

My theory is valve clearances too tight. The valve and seats wear down and then there is constant tension on the cam and rocker pad and no clearance for oil. It my experience machines like this are easily neglected for oil changes too so you get a year or more of degradation combined with tight vales and this is the result I would expect.

Being that tight,would have thought you would have had a no start before we got this far.

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TrevorSchlientz

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Re: in cyl compression - thoughts
Reply #29 - Jan 25^th, 2024 at 6:54am

StitchB wrote on Jan 24^th, 2024 at 10:41am:

TrevorSchlientz wrote on Jan 24^th, 2024 at 3:50am:

StitchB wrote on Jan 24^th, 2024 at 12:03am:

The wear on that cam is massive, a better question is what caused it?

My theory is valve clearances too tight. The valve and seats wear down and then there is constant tension on the cam and rocker pad and no clearance for oil. It my experience machines like this are easily neglected for oil changes too so you get a year or more of degradation combined with tight vales and this is the result I would expect.

Being that tight,would have thought you would have had a no start before we got this far.

Yeah, its not a perfect theory. Smiley

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