Evo top end questions
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Intermediate
Joined: Jun 2009
Posts: 26
Likes: 2
From: Missouri
Evo top end questions
So the adventure continues.
Started top end today. Took rear head off and saw something I have never seen.
Now understand I have only worked on car motors before.
The carbon on the piston had a white ridge in it. exhaust valve is white with what look to me like heavy carbon build up on the heads.
So here are some pics. piston top. Head. Inside exhaust port.
The rear head gasket had been leaking that's what started all this.
So just clean it up real good put it back together? Or am I screwed and have to redo the heads? It was a 1988 FLHTP with the best guess of 75k on it. Stock except S&S Super E and Dual Exhaust. If read my it's been an eventful year post you will understand moneys tight.
Any advise would be greatly appreciated.
Started top end today. Took rear head off and saw something I have never seen.
Now understand I have only worked on car motors before.
The carbon on the piston had a white ridge in it. exhaust valve is white with what look to me like heavy carbon build up on the heads.
So here are some pics. piston top. Head. Inside exhaust port.
The rear head gasket had been leaking that's what started all this.
So just clean it up real good put it back together? Or am I screwed and have to redo the heads? It was a 1988 FLHTP with the best guess of 75k on it. Stock except S&S Super E and Dual Exhaust. If read my it's been an eventful year post you will understand moneys tight.
Any advise would be greatly appreciated.
Stellar HDF Member
Joined: Apr 2009
Posts: 3,039
Likes: 11
From: Northern Ontario
I don't know for sure, no oil on heads and pistons. For the milage if the top end has never been apart I'd say there normal. Really depends how it was ridden. Did you pull the jugs to check for scoring and measure for roundness? Any idea what last compression reading was befoe head gasket went? If money is tight and theres no scoring I'd say clean up the heads and check them for any leaking. generally I'll let them sit overnite filled with gas and see if they leak, poor mans test.
Probably wnat to give the carb a good cleaning as well seeing as its off.
Probably wnat to give the carb a good cleaning as well seeing as its off.
Thread Starter
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Intermediate
Joined: Jun 2009
Posts: 26
Likes: 2
From: Missouri
Ride a lot 2 up highway. Love road trips. Don't ride like I stole it. Well not all the time.
No idea what the compression was. But it ran great. I hadn't noticed any power loss or smoking.
I can check for scoring and do a poor man test. Thanks.
But without a Micrometer how to I measure for roundness?
No idea what the compression was. But it ran great. I hadn't noticed any power loss or smoking.
I can check for scoring and do a poor man test. Thanks.
But without a Micrometer how to I measure for roundness?
Stellar HDF Member
Joined: Jun 2006
Posts: 3,481
Likes: 11
From: NJ
If it were me there wouldn't be any hesitation. I'd be tearing it down. With 75K on it it no doubt is time for at least rebuilding those heads. Have them cleaned up good and check the shape of the seats, valves and guides. Then I would have those jugs brought to a shop to check the deck height, bore and such. From there you can decide at least if you can get away with a hone or bore job.
Other things to consider if the shape of the rods and crank run out too.....
Just finished mine myself. Although mine were looking more like a rich condition because I ran a Super G w/Thunderjet which was way overkill. Nowe I run a E and I gained HP and torque. Couldn't be happier.
2 cents
Other things to consider if the shape of the rods and crank run out too.....
Just finished mine myself. Although mine were looking more like a rich condition because I ran a Super G w/Thunderjet which was way overkill. Nowe I run a E and I gained HP and torque. Couldn't be happier.
2 cents
Seasoned HDF Member
Joined: Aug 2007
Posts: 8,195
Likes: 3,085
From: NW AR
Why did you tear it down? That is, was something wrong? I would concentrate on whatever the tear down reason was if money is that tight. If everything was working fine before and it was just a carbon buildup problem or an oil leak, clean it up, put it back together and do a proper top end when the funds and time are there.
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Club Member
Joined: Feb 2008
Posts: 18,575
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From: Norfolk, VA
While you have the rear head off now is the time to remove the valve springs and do a thorough cleaning of the valves. Lapping the valve seats is also a good move. Your valve guides are probably good if your engine was not consuming any oil. Replace the valve guide seals for good insurance.
It would also be a good move to remove the front head and check it out too. You could get by with doing the least amount of work but you take the risk of having to do the job a second time. Take the extra time now as opposed to later. Yes, cost is a factor but it's your decsion to make overall...Having taken short cuts myself in the past, it's crap shoot and rolling snake-eyes happens when you are on the side of the road in no man's land!!
It would also be a good move to remove the front head and check it out too. You could get by with doing the least amount of work but you take the risk of having to do the job a second time. Take the extra time now as opposed to later. Yes, cost is a factor but it's your decsion to make overall...Having taken short cuts myself in the past, it's crap shoot and rolling snake-eyes happens when you are on the side of the road in no man's land!!
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Stellar HDF Member
Joined: Apr 2009
Posts: 3,039
Likes: 11
From: Northern Ontario
Why did you tear it down? That is, was something wrong? I would concentrate on whatever the tear down reason was if money is that tight. If everything was working fine before and it was just a carbon buildup problem or an oil leak, clean it up, put it back together and do a proper top end when the funds and time are there.
Stellar HDF Member
Joined: Jun 2006
Posts: 3,481
Likes: 11
From: NJ
My heads were fine but decided to go with a rebuild and deck them at the same time.