evo 80" motor help please
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Cruiser
Joined: May 2005
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evo 80" motor help please
After a ride the other day, I noticed something fairly disturbing on my bike. On the rear cylinder, between the where the cylinder mates with the case, I had a small amount of oil bubbling from the seam. Any ideas on how big of a deal this is and how to fix? Thanks.
HDF Community Team
Joined: Dec 2005
Posts: 5,379
Likes: 2,574
From: NC USA
Cylinder base gasket - common on these. Requires disassembling the top end. (exhaust, intake, rocker boxes, heads, cylinders)
Depending on the mileage of the engine, an experienced mechanic can do all that without changing the rings, but best to figure on piston rings. If the bores and pistons are good, just hone them with a 240 ball-flex hone.
If you did it yourself, about 65.00 (+ or -) for gaskets, 35.00 for rings.
The design of these engines makes for a great deal of expansion and contraction. When the gaskets get old, they will get brittle and leak due to the "movement" of the metal parts. Being conscious of this, one of the things that can cause that gasket to fail is running the engine at heavy load and/or high rpm before it has a chance to warm-up. And on rare ocassion, a cylinder/head stud can come loose in the crankcase, but that's not generally an issue.
Again, it's a common location for a leak on an Evo engine, but certainly NOT something that will constantly give trouble....
Depending on the mileage of the engine, an experienced mechanic can do all that without changing the rings, but best to figure on piston rings. If the bores and pistons are good, just hone them with a 240 ball-flex hone.
If you did it yourself, about 65.00 (+ or -) for gaskets, 35.00 for rings.
The design of these engines makes for a great deal of expansion and contraction. When the gaskets get old, they will get brittle and leak due to the "movement" of the metal parts. Being conscious of this, one of the things that can cause that gasket to fail is running the engine at heavy load and/or high rpm before it has a chance to warm-up. And on rare ocassion, a cylinder/head stud can come loose in the crankcase, but that's not generally an issue.
Again, it's a common location for a leak on an Evo engine, but certainly NOT something that will constantly give trouble....
Supporter
Joined: Jul 2008
Posts: 414
Likes: 340
From: Brick NJ
Yeah my 90 1200 sportster is leaking on the lower front. If your good and your motor dosn't require a rebuild, I did it on buddies bike in a day. Mine's gonna take longer because the paint on my cylinders and heads are peeling off and looks like ****.
Road Warrior
Joined: Jul 2005
Posts: 1,655
Likes: 17
From: The Frozen Tundra
Here's my fix from a while ago without removing any bolts:
This is a great thread for people who are able to tear the top end apart and then reassemble it. For those who are not able or feel they are not experienced enough I have an easy DIY fix for base gasket leaks... Go to the automotive store and pick up some Permatex flowable silicone windshield & glass sealer. The # on my tube is 65AR. Clean and dry surfaces to be sealed, apply glass sealer onto leak source, remove excess, let cure for 24 hours.
I used this product/method on my '91 FXRP and had no leaks after. Supposedly the glass sealer seeps it's way into the effected area sealing from the outside all the way to the inside and because it's silicone it can withstand the temperature of the motor.
There's your "Do It Yourself" for the day.
I used this product/method on my '91 FXRP and had no leaks after. Supposedly the glass sealer seeps it's way into the effected area sealing from the outside all the way to the inside and because it's silicone it can withstand the temperature of the motor.
There's your "Do It Yourself" for the day.
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Cruiser
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Bike has 60,000 miles on it. I bought it with 36,000 and have not touched it motor-wise, but it supposedly had just had the top end done. If I can get it to last through the season with the glass sealer, maybe I'll make a winter project out of the motor. I did a Baker 6 speed conversion last winter, sold my snowmobile so I'll need something to do and the wife just bought a new '09 Street Bob so no need to mess with that either. I may need help from you guys on what to do to my 80" Evo to help maintain a little pride while she's walking away from me at every stop.
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HDF Community Team
Joined: Dec 2005
Posts: 5,379
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From: NC USA
don't worry
Bike has 60,000 miles on it. I bought it with 36,000 and have not touched it motor-wise, but it supposedly had just had the top end done. If I can get it to last through the season with the glass sealer, maybe I'll make a winter project out of the motor. I did a Baker 6 speed conversion last winter, sold my snowmobile so I'll need something to do and the wife just bought a new '09 Street Bob so no need to mess with that either. I may need help from you guys on what to do to my 80" Evo to help maintain a little pride while she's walking away from me at every stop.
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