Cylinder base gasket leaking oil.

[4DogsanaHog]

It's a 1999 Heritage Softail Classic with 53,000 miles. The bike does not burn oil but the rear cylinder is leaking oil through the cylinder base gasket. My question is should I just pull the cylinder and leave the piston on the connecting rod or should I remove the wrist pin clip, tap the wrist pin out some and leave the piston in the cylinder then replace the base gasket, as to keep the piston rings in place?

[wfolarry]

I just pull the cylinder off.

[4DogsanaHog]

So I can just pull the cylinder off, replace the gasket and put it back together. No need to hone the cylinders?

[Ohio HD]

The cylinder can be placed back on to the piston. Just check ring spacing as you would on a new installation.

[4DogsanaHog]

Thanks for the Replies. You have just saved me a lot of work. Thanks again to both of you.

[4DogsanaHog]

I think I will just remove the cylinders. I don't think relaxing the rings will do anything negative. I  was just worried about the seating of the rings. One more question. What is the torque for tightening the base bolts (nuts) and head bolts?

[Deye76]

Usually the cylinder base and/or the engine case surfaces are not flat when a rear base gasket on a Evo leaks. Might want to consider this-https://www.haydensm6.com/tof_single.htm

[4DogsanaHog]

Is there an easy way to check flatness of the engine case?

[Ohio HD]

You might try using a precision straight edge and very thin feeler gauges. Ideally a dial indicator mounted and passed across the case service would tell.

[4DogsanaHog]

Ok, so what would be the tolerance? .001, or less? .0001?

[Hossamania]

Unless I were planning on tearing it completely down if necessary to have the case machined and rebuild the motor, I would just put a new gasket on it and ride. The previous one lasted 22 years.

[thumper 823]

Usually, the Evo will get a pucker around the studs.
Pull the studs and choose your weapon to flatten it all out.
Install better grade stud.
Don't get any shavings dwn inside of course.
   Or take the case halves to the proper machine shop.
choices.

[RTMike]

The stock gaskets were crap,replace then with cometic gaskets and go.

[tdrglide]

In the past I have replaced leaking stock with James base gaskets. Last one I did  was with Cometic. Good time to go with a thinner head gaskets usually too

[thumper 823]

If ya have Vergin heads, it's a great time to rip at least 0.50 off them.

[Ohio HD]

It's a 1999 Heritage Softail Classic with 53,000 miles. The bike does not burn oil but the rear cylinder is leaking oil through the cylinder base gasket. My question is should I just pull the cylinder and leave the piston on the connecting rod or should I remove the wrist pin clip, tap the wrist pin out some and leave the piston in the cylinder then replace the base gasket, as to keep the piston rings in place?

You should read this post about base gasket leak and cure.

https://harleytechtalk.com/htt/index.php/topic,115559.0/all.html

[jsachs1]

Check for a possible stud pulling out. If everything checks OK, get some "Pig Tails" and install, with a fresh metal COMETIC base gasket.
John

[SixShooter14]

for what it's worth...I did the pigtails, metal gaskets, and had the cylinder bases 'surfaced' in early 2020 and after only 6k miles have no leaks at all..... It doesn't hurt to try all the remedies.

(also new studs and head 'nuts' bored the cylinders and bumped compression a bit, but that's neither here nor there)

[Hillside Motorcycle]

Evo, (and T/C for that matter) did not come from HD with any machining done to the cylinder base.
"As cast" surface only.
We mount the cylinder in a fixture, with the ID running on true C/L, and then skim machine the cylinder base.
The base is then totally perpendicular to the bore C/L.

[Hossamania]

Call California Phil, a vendor on their site.

[aswracing]

If ya have Vergin heads, it's a great time to rip at least 0.50 off them.

Half an inch off the heads?

Good luck with that.

[thumper 823]

I think most people can read beyond a typo?
To clarify  0.050
There, feel better?

[4DogsanaHog]

Just curious. How much more power would you get by shaving .050 off the heads? Or what difference would shaving .050 off the heads? I have a set of like new  very low mileage heads for my Evo. They are shaved down to .060. Maybe I should install these?

[thumper 823]

Check your clearances as per SOP.
And install them!
You will have upped your CR a point or two.
Slippery slope and it is the way to travel.

[fleetmechanic]

When I attended the factory police mechanics classes  in 1992 they were already on the 14th version of the base gasket since 1984.