HarleyTechTalk

I've got a 2020 CVO Road Glide getting up there in mileage. Everything feels fine but this winter I am going to have some preventative maintenance done along with a compression test.

Aside from the CR480 cam, the motor is completely stock. Can anyone inform me what compression values would be considered healthy during this test?

Thank you!

A dynamic compression test wont tell you much unless you have a trend.  Math and actually have been pretty different on CR cams.  I would suggest a proper leak down at bottom, mid and top.  This will give you a better idea of valve and ring seal.

Quote from: hrdtail78 on November 13, 2023, 09:30:07 AMA dynamic compression test wont tell you much unless you have a trend.  Math and actually have been pretty different on CR cams.  I would suggest a proper leak down at bottom, mid and top.  This will give you a better idea of valve and ring seal.

Thank you. He's performing a leak down test as well.

Both cylinders still cranking over 250. Rear leak down result was 6%, front result was 2%. I only needed a new front compression release. Not bad for over 144,000 miles!

I do the math over and over again using popular engine displacement calculators, but when it comes to the CR480 the numbers on the sheet are always lower than the live compression testing - certified compression gauge. Just Saying.

Quote from: Sunny Jim on December 12, 2023, 06:05:41 PMI do the math over and over again using popular engine displacement calculators, but when it comes to the CR480 the numbers on the sheet are always lower than the live compression testing - certified compression gauge. Just Saying.

I guess I'm not following. Should I be concerned with the results they reported?

Please keep in mind I am not mechanical in any sense of the word or very knowledgeable about this stuff in general. Your patience is appreciated!

Quote from: Sunny Jim on December 12, 2023, 06:05:41 PMI do the math over and over again using popular engine displacement calculators, but when it comes to the CR480 the numbers on the sheet are always lower than the live compression testing - certified compression gauge. Just Saying.

A gauge cert is only good until it isn't. I would check it against a couple of gauges.

https://harleytechtalk.com/htt/index.php/topic,120921.msg1449128.html#msg1449128

Quote from: Ohio HD on December 14, 2023, 08:52:48 PMA gauge cert is only good until it isn't. I would check it against a couple of gauges.

 

If an instrument has a current calibration, it should be trusted.
Once you start comparing, which one do you trust?

Quote from: Dan89flstc on December 15, 2023, 06:18:09 AMIf an instrument has a current calibration, it should be trusted.


Once you start comparing, which one do you trust?

If they stay in calibration forever, why would you ever retest? He said certified, not when it was certified. That's why I asked.


The three that agree.

Quote from: scott7d on December 14, 2023, 05:34:53 PMI guess I'm not following. Should I be concerned with the results they reported?

The numbers look fine to me, I wouldn`t reject an aircraft engine with those numbers.

Keep in mind, compression test and leak down tests are done without the engine running, they are not an actual simulation of the engine condition.

Compression and leakdown tests are most valuable when you have a record of compression /leakdown tests from when the engine was new, and done occasionally thereafter, such as an annual inspection on an airplane engine.

I don`t see any reason to do this on any automotive application.

The most important indicators of engine condition are performance and oil consumption.

Quote from: Ohio HD on December 15, 2023, 06:21:06 AM

Quote from: Dan89flstc on December 15, 2023, 06:18:09 AMIf an instrument has a current calibration, it should be trusted.


Once you start comparing, which one do you trust?

If they stay in calibration forever, why would you ever retest? 


The three that agree.

 I said if the instrument has a current calibration...

Quote from: Dan89flstc on December 15, 2023, 06:52:22 AMThe most important indicators of engine condition are performance and oil consumption.

In those regards, it still feels great. Within a 5,000-6,000 mile interval I may need to put a quart or two in it depending on the style of riding, but it's been like that since day one. I believe HD says one quart every 1,500 miles is "normal"....wow....imagine that. The bike is not consuming it anywhere close to that.

Quote from: scott7d on December 16, 2023, 10:47:24 AM

Quote from: Dan89flstc on December 15, 2023, 06:52:22 AMThe most important indicators of engine condition are performance and oil consumption.

In those regards, it still feels great. Within a 5,000-6,000 mile interval I may need to put a quart or two in it depending on the style of riding, but it's been like that since day one. I believe HD says one quart every 1,500 miles is "normal"....wow....imagine that. The bike is not consuming it anywhere close to that.

Are the heads still vented to the air cleaner?  Bob

 "over 144,000 miles!"

"Are the heads still vented to the air cleaner?  Bob"

At this amount of miles probably doesn't matter.

Quote from: FXDBI on December 16, 2023, 12:08:15 PMAre the heads still vented to the air cleaner?  Bob

Yes. I've always put enough oil in to go about halfway up the stick when hot. Whenever I remove my filter to wash it, I've never had excess oil in the elbow/throttle body.

I see so many people do modifications such as head breathers and so on. But the folks out there logging big miles (80,000-100,000 miles a year) do minimal modifications to their bikes and have no issues at all. Most of the heavy hitters I follow didn't even upgrade their mufflers.

It's funny because you hear so many people rant about "getting the HD junk out of there". In the long distance world, keeping things as close to stock as possible has been more successful. The weekend warriors chase the horsepower and have problems.

Quote from: Ohio HD on December 15, 2023, 06:21:06 AM

Quote from: Dan89flstc on December 15, 2023, 06:18:09 AMIf an instrument has a current calibration, it should be trusted.


Once you start comparing, which one do you trust?

If they stay in calibration forever, why would you ever retest? He said certified, not when it was certified. That's why I asked.


The three that agree.

For the record.
I send my gauge and other tools off for calibration every year.
A receive a certificate of accuracy via the pressure testing laboratory of my choice.

Quote from: scott7d on December 17, 2023, 02:31:06 PM

Quote from: FXDBI on December 16, 2023, 12:08:15 PMAre the heads still vented to the air cleaner?  Bob

Yes. I've always put enough oil in to go about halfway up the stick when hot. Whenever I remove my filter to wash it, I've never had excess oil in the elbow/throttle body.

I see so many people do modifications such as head breathers and so on. But the folks out there logging big miles (80,000-100,000 miles a year) do minimal modifications to their bikes and have no issues at all. Most of the heavy hitters I follow didn't even upgrade their mufflers.

It's funny because you hear so many people rant about "getting the HD junk out of there". In the long distance world, keeping things as close to stock as possible has been more successful. The weekend warriors chase the horsepower and have problems.

I find it odd you would disparage a large portion of this forum by posting the above after posting the below, plenty of worked bikes doing big miles, just not in your circle it would seem.

"Please keep in mind I am not mechanical in any sense of the word or very knowledgeable about this stuff in general. Your patience is appreciated!"

Quote from: Hilly13 on January 27, 2024, 02:28:17 PM

Quote from: scott7d on December 17, 2023, 02:31:06 PM

Quote from: FXDBI on December 16, 2023, 12:08:15 PMAre the heads still vented to the air cleaner?  Bob

Yes. I've always put enough oil in to go about halfway up the stick when hot. Whenever I remove my filter to wash it, I've never had excess oil in the elbow/throttle body.

I see so many people do modifications such as head breathers and so on. But the folks out there logging big miles (80,000-100,000 miles a year) do minimal modifications to their bikes and have no issues at all. Most of the heavy hitters I follow didn't even upgrade their mufflers.

It's funny because you hear so many people rant about "getting the HD junk out of there". In the long distance world, keeping things as close to stock as possible has been more successful. The weekend warriors chase the horsepower and have problems.

I find it odd you would disparage a large portion of this forum by posting the above after posting the below, plenty of worked bikes doing big miles, just not in your circle it would seem.

"Please keep in mind I am not mechanical in any sense of the word or very knowledgeable about this stuff in general. Your patience is appreciated!"

I appreciate you taking the time to share that perspective 

Scott, 144,000 miles on a 2020 CVO is significant amount of miles.  Seems like it got a good leak down.  Seems like it should be good to ride several thousand more miles

Quote from: FLSTFIDave on January 28, 2024, 04:49:55 AMScott, 144,000 miles on a 2020 CVO is significant amount of miles.  Seems like it got a good leak down.  Seems like it should be good to ride several thousand more miles

149,000 now and still humming along like a champ!

We'll be in Maryville TN the beginning of April. We should try to meet up!