Harley compression reading

tew45 · 08-21-2007, 05:24 PM

Hey folks,
My Harley has readings of 90# forward and almost 95# in reverse. I think this is a good reading. I installed a new piston and rings but did not bore for the next size. everything measured to factory specs. I don't know if the cylinder was round enough. I used a century hone to rough it up and it looked round. Now to the point..... Can some of you check yours and see what compression reading you get. Especially one with a brand new top end. Mine runs a little weak up hills but I think my muffler needs cleaning out.

tew45 · 08-25-2007, 01:31 AM

Youall aren't helping much. I have heard from the BU set that the HD standard compression readings are a lot higher than 90#. Since it doesn't say so in the manual the only way we will find out for sure is to get you Harley owners to report your findings. Yes! I am retired and have time to do it and you have 42 kids and don't have the time. I know the drill for I had a ew kids myself. But a compression check doesn't take long if you have the gauge. Help us all and list compression and piston size! Some say 90# is good and some say that 90# is a disaster. What is it?

NO NO NO E-Z-GO! · 08-25-2007, 06:36 AM

I believe I got a reading of 75 on one Harley that was actually blowing its fuel/air mixture out the side of the head gasket. It still ran. That's amazing. I got a reading of 120 on a newly rebuilt Robin 3PG. IMHO, 90 is a bit low.

tew45 · 08-25-2007, 08:58 PM

You are talking about two different engines. There cannot be a good comparison. A 4 cycle against a 2 cycle again, no comparison. We need to check apples to apples!

NO NO NO E-Z-GO! · 08-25-2007, 09:09 PM

Last time I checked the Robin 3PG was a two cycle.

tew45 · 08-25-2007, 11:39 PM

Sorry bout that, I stand corrected!!!!!!!!!!!!

tew45 · 08-26-2007, 12:08 AM

Hey folks,

Different engines have different specks and different compression readings. I don't know about all these other engines so you are asked to educate me some.

The readings that Golf Cart Care list as normal are 80 forward and 85 reverse. I would like to find out if this is true or not. They say that 10 to 15 lbs above that indicate carbon build up or a stopped up muffler. My piston and rings are new and i'm sure I don't have carbon build up and I still get 90 -- 93 readings. So If they are right on their compression readings, I may have a stopped up muffler, which is highly possible. Other engines readings are not revelent but are still welcome for I will see all engines eventually. I am only 70 years old but I will live to be 100 or more and still be working my rear off. So don't get pissy with me if I don't know your business just explain it to me and we will be A OK.

NO NO NO E-Z-GO! · 08-26-2007, 08:33 AM

Ok then, I will leave the other manufacturers out of it. Just thought that would be a reference.

All I can offer is that I did get a reading of 75psi on a 1981 Harley. The head gasket was so bad that it was blowing some of the fuel/oil/air mix out the side of it. It still ran on that until they put a BU rebuild in it. I have not seen it move since.

tew45 · 08-26-2007, 02:01 PM

Thank you for the input. I do value your information very much. Other engines are of importance to me also. I do not own a club car but hope to own one at first opportunity. I was just trying to set a base line for a definite top end rebuild on the HD. There has been so many different opinions from a lot of people that I wanted that settled. Your cart with 70# and a leaky head gasket was definitely interesting and a worthy input. When I first tried to run my Harley, I just did only what was necessary to get it to run. It ran for a few days (poorly but it ran) then I was a fem yards from where I kept it and it quit starting. I found that it would run in reverse so I got to the parking place and it never started again. I checked compression and it was 60# forward and not much more in reverse. On tear down I found piston and rings worn out. Cylinder in spec for std. replacement. But the odd thing was the crank case was 1/3 full of water and had been for a long time. Sorry I was sharp, no need to be. I was wrong. Now I have to go see What I can do for a friends G9 (The exhaust valve and push rod do not move,

NO NO NO E-Z-GO! · 08-26-2007, 07:06 PM

I think you should drain that water out ASAP.

Is the push rod broken on the 285? Cam lobe worn?

08-21-2007, 05:24 PM	#1
tew45 Gone Wild Join Date: Aug 2007 Location: North Texas Posts: 2,312	Harley compression reading Hey folks, My Harley has readings of 90# forward and almost 95# in reverse. I think this is a good reading. I installed a new piston and rings but did not bore for the next size. everything measured to factory specs. I don't know if the cylinder was round enough. I used a century hone to rough it up and it looked round. Now to the point..... Can some of you check yours and see what compression reading you get. Especially one with a brand new top end. Mine runs a little weak up hills but I think my muffler needs cleaning out.

08-25-2007, 01:31 AM	#2
tew45 Gone Wild Join Date: Aug 2007 Location: North Texas Posts: 2,312	Re: Harley compression reading Youall aren't helping much. I have heard from the BU set that the HD standard compression readings are a lot higher than 90#. Since it doesn't say so in the manual the only way we will find out for sure is to get you Harley owners to report your findings. Yes! I am retired and have time to do it and you have 42 kids and don't have the time. I know the drill for I had a ew kids myself. But a compression check doesn't take long if you have the gauge. Help us all and list compression and piston size! Some say 90# is good and some say that 90# is a disaster. What is it?

08-25-2007, 06:36 AM	#3
NO NO NO E-Z-GO! Gone Wild Join Date: Dec 2006 Location: ComplainAboutNoNo'sProfile-Ville Posts: 4,995	Re: Harley compression reading I believe I got a reading of 75 on one Harley that was actually blowing its fuel/air mixture out the side of the head gasket. It still ran. That's amazing. I got a reading of 120 on a newly rebuilt Robin 3PG. IMHO, 90 is a bit low.

08-25-2007, 08:58 PM	#4
tew45 Gone Wild Join Date: Aug 2007 Location: North Texas Posts: 2,312	Re: Harley compression reading You are talking about two different engines. There cannot be a good comparison. A 4 cycle against a 2 cycle again, no comparison. We need to check apples to apples!

08-25-2007, 09:09 PM	#5
NO NO NO E-Z-GO! Gone Wild Join Date: Dec 2006 Location: ComplainAboutNoNo'sProfile-Ville Posts: 4,995	Re: Harley compression reading Last time I checked the Robin 3PG was a two cycle.

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08-25-2007, 11:39 PM	#6
tew45 Gone Wild Join Date: Aug 2007 Location: North Texas Posts: 2,312	Re: Harley compression reading Sorry bout that, I stand corrected!!!!!!!!!!!!

08-26-2007, 12:08 AM	#7
tew45 Gone Wild Join Date: Aug 2007 Location: North Texas Posts: 2,312	Re: Harley compression reading Hey folks, Different engines have different specks and different compression readings. I don't know about all these other engines so you are asked to educate me some. The readings that Golf Cart Care list as normal are 80 forward and 85 reverse. I would like to find out if this is true or not. They say that 10 to 15 lbs above that indicate carbon build up or a stopped up muffler. My piston and rings are new and i'm sure I don't have carbon build up and I still get 90 -- 93 readings. So If they are right on their compression readings, I may have a stopped up muffler, which is highly possible. Other engines readings are not revelent but are still welcome for I will see all engines eventually. I am only 70 years old but I will live to be 100 or more and still be working my rear off. So don't get pissy with me if I don't know your business just explain it to me and we will be A OK.

08-26-2007, 08:33 AM	#8
NO NO NO E-Z-GO! Gone Wild Join Date: Dec 2006 Location: ComplainAboutNoNo'sProfile-Ville Posts: 4,995	Re: Harley compression reading Ok then, I will leave the other manufacturers out of it. Just thought that would be a reference. All I can offer is that I did get a reading of 75psi on a 1981 Harley. The head gasket was so bad that it was blowing some of the fuel/oil/air mix out the side of it. It still ran on that until they put a BU rebuild in it. I have not seen it move since.

08-26-2007, 02:01 PM	#9
tew45 Gone Wild Join Date: Aug 2007 Location: North Texas Posts: 2,312	Re: Harley compression reading Thank you for the input. I do value your information very much. Other engines are of importance to me also. I do not own a club car but hope to own one at first opportunity. I was just trying to set a base line for a definite top end rebuild on the HD. There has been so many different opinions from a lot of people that I wanted that settled. Your cart with 70# and a leaky head gasket was definitely interesting and a worthy input. When I first tried to run my Harley, I just did only what was necessary to get it to run. It ran for a few days (poorly but it ran) then I was a fem yards from where I kept it and it quit starting. I found that it would run in reverse so I got to the parking place and it never started again. I checked compression and it was 60# forward and not much more in reverse. On tear down I found piston and rings worn out. Cylinder in spec for std. replacement. But the odd thing was the crank case was 1/3 full of water and had been for a long time. Sorry I was sharp, no need to be. I was wrong. Now I have to go see What I can do for a friends G9 (The exhaust valve and push rod do not move,

08-26-2007, 07:06 PM	#10
NO NO NO E-Z-GO! Gone Wild Join Date: Dec 2006 Location: ComplainAboutNoNo'sProfile-Ville Posts: 4,995	Re: Harley compression reading I think you should drain that water out ASAP. Is the push rod broken on the 285? Cam lobe worn?

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