Sportster Rocker Boxes on an EVO

joeg2246 · #1 10-17-2007, 05:26 AM

I have been having a problem with the rocker boxes leaking on my 89 FXSTC. I have been told the cure would be to replace the existing rocker boxes with a newer set of Sportster rocker boxes. Will this cure my problem and have any of you heard of this mod before?

Javieret · #2 10-17-2007, 08:30 AM

I don't think this be so easy. I believe that Sportster rocker boxes won't fit in an Evo 1340 motor, because the motor design is not the same.

Maybe I be wrong, but I've never heard nothing like that. Maybe you should try to get better gaskets for your rocker boxes, not the Harley-Davidson ones. Take a look at Cometic Gaskets or any other aftermarket manufacturer. I think this would be the cheapest solution.

Regards from Spain,

Javi

Dr.Hess · #3 10-17-2007, 09:35 AM

I heard of doing this years ago to get an Evo to fit in a Shovelhead frame. My friend, who was a super hack mechanic, but unfortunately a hacked everything even if the right part and/or tool was available, said that you could put the 883 rocker boxes on a 1340 Evo, then slid the whole motor into a Shovelhead frame. I never saw one and he's dead now so I can't ask him.

joeg2246 · #4 10-19-2007, 08:54 AM

Took the bike back to the indy shop who replaced the rocker box gaskets the first time. He said he has it sealed for good. No leaks on the way home and none on my way in to work. I hope he is right. By the way he said he tried something different, but, would not offer up what he did.

Calwoodbutcher · #5 10-19-2007, 10:35 AM

He would not tell you. You have got to be kidding. Did you ask?

Dr.Hess · #6 10-19-2007, 10:58 AM

JB Weld?

Calwoodbutcher · #7 10-19-2007, 12:43 PM

You owe me a keyboard Hess.

joeg2246 · #8 10-19-2007, 01:44 PM

I guess I did not try to pry the info out of him. All I know is I asked what he did and he said he tried something different and he felt pretty positive it would work. I hope he did not use the JB Weld method

hard_head · #9 10-20-2007, 11:32 AM

Don't worry... sounds like he used duct tape - if not JB Weld.

joeg2246 · #10 10-20-2007, 03:18 PM

How about whatever it is he tried it did not work. Oil is now pouring out of the rocker boxes. Any ideas? Anyone? I need some advice here as to what to do. I am thinking of replacing both rocker boxes with EVO boxes not Sportster boxes.