OK, rear rocker box gasket basically blew out and was spraying oil nicely all over my bike. Naturally it was first evident on the right side next to the air cleaner, making me think initially that it was breather or check valve related.

Anyway, pulled the rocker box, cleaned and replaced all the gaskets (cleaned rocker box, installed new gaskets). Reinstalled everything pretty much as per the service manual except that I had to torque some of the bolts by "feel" since there's no room for a torque wrench due to the frame. When taking apart the rocker the bolts were nowhere near the torque specs - they were REALLY loose.

All is dry again. However, I now have a somewhat intermittent tapping at low RPMs. Not real loud, but I notice it. I'm replacing the heads over the winter and will probably only get another 200-300 miles on the bike before then. Oh, it's a '92 Heritage EVO w/37k.

I'm thinking maybe that either:

1) Tightened rocker arms/box too much.
2) Also just changed oil. Lifter maybe not acting nice?
3) Gasket thicker, resulting in less clearance.

Any ideas or feedback?

 

It sounds like you have a hydraulic lifter that may be collapsing when the bike is idling and oil pressure is lower. Does it go away at higher rpms? My second thought is that somehow the rocker itself is lightly contacting the rocker box maybe in the area of the webbing? Post back when you find the problem...................BG

 

are you sure the pushrods went back in the same tubes? They are different lengths.

 

Yeah, it does sound like a lifter that's not cooperating. The funny thing is that it comes and goes, and frankly that it seems to happen AFTER the bike runs a bit rather than immediately - which is when a collapsing lifter would normally act up the most.

The pushrods were absolutely installed correctly. At least in the right tubes

 

The lifters on the EVO were not made out of the same metal they are using now, and it is common to replace the lifters at 25k miles. The aftermarket replacement lifters are made much better now then the originals were.

 

Yeah, I'm planning a much more extensive set of work in a month or so - heads, cam, pistons, rings, lifters, rocker arms, pushrods, carb, intake, ignition.... Oh, man is that going to hurt the wallet. Anyway, I just replaced the rocker gaskets to get in some enjoyable riding without being self-lubricated for another month or so.

Planning on using Crane tappets. Any thoughts?

 

Nothing wrong with Crane's! If the cam you go with has you pushing it in the higher rpm's a lot, then might go with Jims hydrosolid lifters.

 

Well, there's some controversy there. I'm going with the Edelbrock stuff. I like the head and piston design, plus those heads allow their .600 lift cam without worrying about collapsing valve springs. Of course the HD shops don't like Edelbrock and some other folks have their opinions. I've used Edelbrock stuff on SB Chevy's, and they've always done their homework. Besides, Wink Eller seems to like the stuff just fine. The torque/power curves on that setup will probably have me staying below 4800rpm. Peak TQ on the 80" Evo should be at around 4600 depending on the pipes.

Anyhow, I was thinking about the Jims stuff - including the big axle lifters. Just still leaning toward Crane.