Middle rocker box gasket keeps blowing out

[Blackhawks]

Hi,

I have a 1996 RK EFI. I had the top end rebuilt over the winter, while it was apart I decided to make a few modifications that have been a cursing every since.

I put in an andrews ev 27 cam, adjustable pushrods, power commander, true dual pipes & Arlen Ness fat sucker.

I drilled out the holes on the middle rocker box for the oil return, as oil was coming out of the fat sucker & going all over the bike. This eased some of the oil but I eventually routed it to the ground.


My main problem is that my middle rocker box gasket keeps blowing out on the front & rear cylinder causing the middle rocker box to actually shift & oil starts eventually coming out.

I have tried different manufacturers & nothing seems to stop this from happening. I do notice that riding at higher speeds in excess of 80mph seems to make it happen quicker after putting new gaskets on the top 2 boxes. Thanks for any help in advance.

[Dr.Hess]

I dunno here. Excessive blowby? Timing gear thingie in the cone OK? Umbrella valve thingies OK? Vent hose not blocked? Seems like you have too much pressure in the rocker boxes, so why?

[se2 deuce]

had the problem with oil coming out of breather tried leaving oil level in the middle of the low and high line on the dipstick and that seemed to work. as for the rockers a friend had this problem after a local shop did a head job . they fixed it three times each time it got worse and lasted less time . turned out the first time they did it they warped the covers no doubt from improper tightning of the rocker box bolts because there were no leaks in the covers before they took it apart also make sure they are lined up properly when tightened down because they can shift either way when torquing them down. you may need new covers

[alex_bwls]

same thing happened to me and i added a 2mm thicker gasket and the problem solved.

[Dan89FLSTC]

Sometimes the middle rocker box gets to the point where it will not hold its shape when you tighten the bolts. Time to throw them into the scrap pile...

[FXR2]

I had the same problem. I could shift my middle rocker box piece back and forth with my fingers. I discovered that my top rocker box cover was warped--so much so that when tightened down with the bolts, the opposite corners would touch the middle rocker box piece and leave the other opposite corners and sides loose.

Take your rocker boxes apart and clean the top plates. Place them on a granite or glass countertop and check them for "rocking" from corner to corner. If the do't lay flat on the grantie or glass, either gently sand them or replace them. If you get new ones, check them for trueness. I had to sand a brand new set--warped new out of the box.

If sanding, use a medium grit paper and the same granite or glass countertop. Place the top piece down on the sandpaper and gently do figure 8's until the bottom is true with the surface of the granite or glass. This will also remove the chrome from the gasket surface and make for a better seal.