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I’m preparing to replace the leaking head gasket on the rear cylinder(second time) and decided to do both cylinders and eliminate the base gasket and rocker box seeps. At the risk of starting another thread like the oil threads I am trying to find the best brand of gasket sets or combination of different brands. Next I’m on to methods to rethread the stud holes. All info is welcomed. Maybe I should say my bike is a 1989 FLTC.
Have you determined the reason for the second time?
You are at a slippery slope junction, a great time for some upgrades.
I suspect a case stud may be pulling. I also plan to surface the heads and to check and repair if needed the cylinder. The configuration at this time meets my use and needs well so no upgrades at this time.I will mention at this time that I am an ASE master tech and retired auto instructor so basic mechanical issues will be checked. That said I am happy to hear all recommendations including the experience of others in this repair. I am very aware that I can still learn so all suggestions appreciated.
Studs or any fasteners 30 years old have lost their elasticity.
They will just have a static pull.
The aluminum cylinders are more than likely not Sq with the world at the bottoms.
Any machine shop that can bore and hone your cylinders can also true up the cylinder base as well. I think my guy charged 15 bucks to true mine up. Don't even bother with trying to clean the old gasket off the bottom of the cylinder, as it will be removed when they true it up.
I agree with others: Why did the head gasket fail a second time??? I hope it's not a stud pulling. That's a rough rode to head down.
I used a cometic MLS gasket set on my top end job done this past spring. All is well so far. Good luck with your project. YD
I’m preparing to replace the leaking head gasket on the rear cylinder(second time) and decided to do both cylinders and eliminate the base gasket and rocker box seeps. At the risk of starting another thread like the oil threads I am trying to find the best brand of gasket sets or combination of different brands. Next I’m on to methods to rethread the stud holes. All info is welcomed. Maybe I should say my bike is a 1989 FLTC.
For the head and base gaskets use either James or Cometic steel gaskets and for the rocker box seeps first make sure your rocker boxes haven't warped. Warped rocker boxes (usually the middle one) is the most common cause for rocker box seeps.
As for the case stud holes timeserts are the best fix if you have a problem but helicoils work just fine.
FYI make sure when bolting the base rocker box down that the piston of the cylinder you are working on is at TDC.
By checking both cylinder and head surfaces, you are going to have it fixed correctly. Once that is taken cared of, I would use the following combination:
1. Rocker box gaskets-HD OEM
2. Head gasket-Cometic MLS
3. Cylinder base-Cometic or James with Hayden oil fix.
If you end up fixing or not fixing your case stud hole threads, I would recommend new studs and installed with shoulder down. I believe OEM studs for 89 were smooth studs, and you have to measure how far you install down. I just find the studs with shoulders much easier to install. I would also replace the cylinder bolts.
What's the mileage on your bike? Good time to check other items, such as lifters. Have fun.
Last edited by daven9113; Nov 8, 2018 at 09:59 AM.
I plan on replacing all the studs and am going to do all the stud holes at the same time.I have the helicoil sets but may invest in the time cert tool as it appears to be a better choice. Rocker boxes are dry as they have had the factory gaskets replaced and found to be true at this time. I’ve had this bike about 7 years and am still finding problems that previous owner(s) caused during previous repairs. I have slightly over 60 k on it now. I rode every day until I retired and still try to ride at least 3 days a week. I was leaning toward the cosmetic gaskets so that recommendation was appreciated.
I had trouble removing one of my studs. The double nut worked to remove all of them except one. The stud is long so it would twist and flex with torque applied but not break free. Heat and penetrating oil did not help. Out of desperation, I used what looks to be a homemade die holder (don't remember where I got it) and some sanding screen to clamp on to the stud down low close to the block. That stud came out easy with the improvised tool.
Take a good look at the threads in the block after the old studs are removed, if they look good, those threads should be cleaned really well and use loctite red on the new studs. This thread was helpful to me:
Top End Gasket Selection
