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CVO Technical => EVO => Topic started by: ltank on January 21, 2015, 06:22:52 PM
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When replacing EVO rocker and head gaskets should the base gaskets also be replaced? If replacing head gaskets do I have to
Replace piston rings? Local shop recommended honing the cylinders getting new rings and a valve job. My son went to jail again and I don't want to spend more than needed if I decide to sell it. I am the lien holder and he has not paid a penny that he agreed to. I hoped it up and added a 6 speed. What should I do?
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When replacing EVO rocker and head gaskets should the base gaskets also be replaced? If replacing head gaskets do I have to
Replace piston rings? Local shop recommended honing the cylinders getting new rings and a valve job. My son went to jail again and I don't want to spend more than needed if I decide to sell it. I am the lien holder and he has not paid a penny that he agreed to. I hoped it up and added a 6 speed. What should I do?
Is it the head gaskets leaking or the rocker box gaskets? Not uncommon for Evo rocker box gaskets to leak. If it's only the rocker box gaskets leaking, then leave the heads/cylinders/base gaskets alone unless you're having other issues...
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I guess I will clean it then Ride it to see to make sure. I do think there was a rear cylinder base gasket leak. So it would make sense to do both . Is it necessary to replace piston rings if they are not broken?
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I guess I will clean it then Ride it to see to make sure. I do think there was a rear cylinder base gasket leak. So it would make sense to do both . Is it necessary to replace piston rings if they are not broken?
If you find you have a base gasket leak in addition to a top end leak, then you answered your own question... As far as replacing rings, how many miles are on them? In general, unless they already have high mileage on them, replacing them or not depends on what you see when you take it apart. If the cylinders and rings show more than light wear marks, it's not a bad idea to at least ball hone the cylinders and install new rings. A relatively cheap investment as long as you have the motor apart anyway to replace base gaskets... :2vrolijk_21:
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Ok thanks
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If you pull the heads, you should do the base gaskets. Hayden oil fix is the way to go.
As for the rings, it depends. More than 30K miles, deglaze the just and replace the rings. Less, then read the piston heads to see if they are still sealing good. If the jugs show scoring, then you'll need to rebore and replace the pistons.
If you choose not to replace the rings, don't pull the pistons from the jugs. Just slip the jug up to expose the wrist pin and pull the pin. Then pull the jug with the piston still in it.
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I can not imagine getting into a motor that far without a Hone and new rings. Maybe just race-car past talking but the more round the cylinder the better and you are talking EVO which is at least what 15 years old which has had aLOT of heat cycles in its life.
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I can not imagine getting into a motor that far without a Hone and new rings. Maybe just race-car past talking but the more round the cylinder the better and you are talking EVO which is at least what 15 years old which has had aLOT of heat cycles in its life.
Lots of Evo rings out last the sealing of the base gasket.
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The way to attend to the more than common Evo cyl base gasket leaks, is to machine the cylinder base perpendicular to the bore, and use a Cometic EST gasket. Done.
Piece-o-cake.
Scott
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Did my 1987 evo rocker boxes and base gaskets last year. I checked the cylinder bores and found them clean and still in spec after 80,000 miles. I replaced the rings anyway cuz you just gotta due it if its tore down that far. No problem with the valves either. Remember to follow the torque sequence and formula exactly and your bike will run well.
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The cylinder bases of an Evo are NOT machined, only the spigot, if one looks at them at all.
Very clear to see where the spigot OD was tuned, and then stopped, not touching the base.
The Moco was counting on the paper gasket to suck up any oddities that may be present with those bases, but we all know that wasn't the case.
Again, the proper methodology is to have those machined if there is an issue.
Scott
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need more info
Is it just the rocker box gaskets, if so change them with james gaskets, and torque them to factory specs. A lot of people overtighten these.
If you have a blown head gasket, you would be hearing hearing compression leaking.
If its the base gaskets, replace them with the multi layer steel gasket, check the piston ring wear, now may be a good time to hone the cylinders, and replace the rings.
When my base gasket was leaking, i did everything above, sent the heads out for a stage 2 port, had them milled to raise compression, installed an EV 27 cam, new lifters, and adjustable pushrods, DTT single fire ignition. My brothers still riding that bike 30 k miles later, with no issues. Everybody loves the sound of that cam.