This is my first post. I will be a HD owner in a week or two. My first bike will be a 76' XLCH I'm buying from a friend of mine. As of right now the bike doesn't run and hasn't ran in about 10 months or so.

-My question is what all is involved in a top end rebuild on an old ironhead? I know I need to get the jugs bored and new pistons and rings. But what about cams and lifters? Or valves, or anything else I need to know?

-What are good pistons to go with? Is Wiseco a good brand when it comes to HD parts?

-Whats the stock comp ratio is it 9:1 or 10:1?

-Whats a good website to price this stuff online at? I wanna buy it from the local chopper shop but need to start getting an idea of what im getting myself into financially.

Any advice is apreciated.
Thanks, Woody.

 

why do you think it needs a top end?? did it smoke?? i would say alot of investigating needs to be done before the top end comes apart! if it does need bored then the heads are gonna need help, at the very least guides and a valve job,lifters needs to be checked for wear you can put new rollers on them, lifter guides need checked for wear,cams are fine, unless its leaking i wouldnt pull the side covers(your asking for trouble)as far as pistons go i run trw forged 10 to 1s in mine, the machine work on the jugs is alittle different when you run cast versus forged( the cast piston expands more)

 

+1 on this question. Unless there are specific things indicating the top end needs to be re-done there are other things to take care of first. Here is a thread on how to get a bike running that has sat unused for a while ...

Tips For De-hibernating Your IronHead

If it has been smoking as shepdog says the top end may need attention. Once you get it running and warmed up you can do static compression and leak-down tests. These will help determine what top end work may be needed ...

Cylinder Compression And Leakage Tests For Your Ironhead

If it does need top end work you will need to find a machine shop that is familiar with ironhead engines and has done this work before. They will all tell you that they are expert and can do the work but trust this: many will screw up your engine. It will possibly be better to spend some $s shipping your parts to a known good old-time shop than using a local guy.

The machine shop will need to measure the cylinders to see if and how much honing or boring may be required, and then have the pistons in hand before boring the cylinders.

10:1 Wiseco pistons are a good choice - i have them in my '78. However, they do require some extra tuning. Higher compression requires higher octane fuel and around here the best i can get is 91. I got it running very well by installing an electronic ignition, a VOES, and by retarding the ignition timing from the static setting.

It may be better to stay with stock compression pistons, 9:1 i believe.

Anyway, first get it running! No hurry! If it runs ok, perfect is not required, run it for a year, take care of the dozens of small issues that you will find [electrical, brakes, carb, tires, chain, etc, etc, etc], and leave the top end until next year.

 

The front cylinder is burning oil so the top end needs to be done. Will it be easier to pull the motor and have it on the bench or just do it on the bike?

Thanks for the input,
Woody.

 

No need to pull the motor to do the top end.

You will need these two factory manuals ...
Service manual 99484-78
Parts catalog 99451-78B

The rear rocker cover and cylinder head must be removed as an assembly. The front components can be removed individually.

 

most likley you just need the heads/valve seals rebuilt.. no need to pull the engine or even cylinders..take the heads to napa for the rebuild..last time i did one it cost $40 a head,plus valve seals..while its apart look down the cyl for wear,if they are smooth they are probaly fine,you could have them measured and honed and put in new rings if you want,would be basicly a new top end if its within specs. ..if cylinders are worn or groved have napa or an auto machine shop bore them .030/.060 over..any standard pistons will work fine.no need for high priced stuff on a ironhead

 

Bad news I got it torn apart the other day and the piston is trashed. It even has a chip out of it on the bottom of the skirt. And the rod has been chewing at the crankcase. Not really sure at this point what I'm gonna do.

 

Well at the very least it sounds like you're going get a good education on Ironhead engine rebuild.

 

If you have a chip out of the piston that almost certainly means junk fell into the lower end.
This will require you to remove the engine from the frame and completely take the engine apart.
Then you may find there is further damage that you cannot detect right now.
You have a huge project ahead of you.
If you have not worked on an ironhead engine before, make that a double huge problem facing you.
I do not mean to sound pessimistic, but that is the plain truth.
So give this some serious thought before you get deeper into the water.
pg