Bought my fist bike and just happen to be a 1973 ironhead sportster xlh. The guy I bought it from was planing on making it a fast hard tail bobber but life got in the way. The bike is tore down completely, motor is intact but the heads and jugs are off. Never worked on a Harley before, so looking at this photo. What are my to do's? things to check/look at/replace? I know the obvious, check cylinder, rings, etc... I bring her home next weekend and as things warm up a bit, I'll be starting the build. Thanks for the help, I'm sure Ill have more questions as I go.

 

Looks like a fun project man - I have one going here as well, a 77 bobber build. Your bike looks well cared for from the pics - go over it with a flashlight to make sure nothing is cracked and start asking questions on here if you need help …..this place is awesome:-). Oh yeah post lots of pics - we all want to see what you do with her. What are your plans?

 

Thanks BB, Seeing how it sits now. I would love to upgrade the compression. Would also love to upgrade the cams as well, how hard is that?

Once I get her home I will post more photos. The person that tore her down did a great job of wrapping and labeling every part. I will post photos from start to finish...

 

First purchase is the two factory manuals ...
Service Manual 99484-78
Parts Catalog 99451-78B

They are your most important tools. You can buy these at a local indie motorcycle shop [best choice, support the local guy, you may need him sometime], HD dealer, or put the part numbers into the Google and eBay searches. J&P Cycles may have them also.

While the top end is off there are some simple tests you can do to see if the bottom end [crank bearings etc] is good. If it passes the tests there is no need to dismantle the engine any further [EDIT, unless there are clutch or transmission issues. However those are relatively easy to deal with even if the engine is completely assembled].

The tests are in the factory service manual. I can post some more about them if you want to get started before your manuals arrive.

EDIT#2: AHhhh, i see the service manual in your pic. See page 3-1 for the spec on the sprocket shaft bearing end play, page 3-17 [right side 2/3rds way down page] for the spec on rod bearings, and 3-35 for the procedure to check flywheel end play. Page numbers may differ if your manual is a different edition than mine.

A good machine shop can measure the cylinders for out-of-round etc, and check if they need to be bored, honed or if they are ok as is. If they need to be bored the guy will know what size pistons to order. It is important to check out machine shops carefully. Most modern shops seriously do not know how to set up these vintage iron engines. Nice if you have a shop nearby that knows such engines.

Service the wheel bearings, steering head bearings and swingarm bearings. The latter will be the most difficult.

Replace brake fluid and fork oil. The primary takes 24 oz [1.5 pints] of the same oil that you use for the engine. Most guys use straight 50W, 60W if in a very hot climate, 20W50 for Winter.

Check front brake pads and rear shoes.

1973 is a very good year for IronHeads. You have what appears to be a good one. All the best with this.

 

Thanks for the great info IronMick. I think the owner also has the parts manual. I have the service manual here with me and have been doing some studying. I do know a good machine shop but he doesn't do any boring just for the reason you said. But he did tell me of a guy that does.

Thanks for the help.

 

Head gasket question. Been looking at gasket kits for the cylinders/heads and came across to use a 0.45 vs the standard 0.15 head gasket.

Most gasket kits come with a .015" thick copper head gasket, toss that one in the trash, do not use it. Order up a set of the .045" thick copper head gaskets and use those. The reason being that the spigot, that little lip that sticks up on the jug will hit the head before the head fully compresses the .015" thick gasket, the engine will probably have OK compression, but, because the copper gasket is not completely crushed, oil from the cylinder head drain back holes will be sucked into the cylinder when the pistons are moving down on the intake stroke. Don't believe me? Set the head on the jug and measure the gap between the head and the jug with a feeler gage, it will probably be about .017" or .018". You can mill or file down the spigot or you can use the thicker gasket.

Is there any merit to this? I don't want to probably have good
compression. I want to defiantly have good compression.


Thanks again

 

There is no merit to that quoted comment. There are two uses for the extra thick head gaskets ...

1. They were stock on a few years around 1982. HD used them to lower the compression. Something to do with emissions or other Gov't interference. The are not needed unless an owner really wanted to be year-correct.
2. If the cylinders or heads are in very bad condition, and have been machined so that the spigot is too tall, then the thick head gasket would be useful. It is unlikely that the parts are in such bad condition.

 

Delays, delays, couldn't pick up today do to other commitment I forgot about. So, next Saturday it is. But I have been thinking/looking at what direction I want to go with this project. Still working on the look but I have found the sound I want. . Besides boring out the cylinders, bigger cams. Is there anything I need to do? Stroke or something. Looking at JP http://www.jpcycles.com/product/433-635. Says head set up required? is it necessary to purchase the whole assembly or can I just buy the lobes or (duh, timming dummy) Note to self

If there are any NE Ohio people here. I'm looking at this place for my machine work. http://www.twinhillsiron.com anyone ever use them?

 

Boring cylinders on these bikes is only done if the cylinders are worn. You never do this unless it is absolutely necessary. It can only be done 7 times then you need new cylinders. Overboring does not provide any more power.

I believe the original cams are PB cams. If so then they are very good and there is no need to upgrade. PB+ cams are a common upgrade, but the performance improvement comes on at 4000 RPM. Most riding is done at or below that RPM. They are fun tho, like when doing 3rd gear roll ons side by side with a buddy; or passing big trucks on a windy day. This is a simple upgrade that can be done at any time in a couple of hours - the PB+ cams are a straight bolt-on upgrade - no head work required. I would ride the bike with the current setup for the first year. .

The R5 cams do require some head work otherwise the valves will touch the pistons

Decide on top end work [cylinders, pistons] after you have the parts examined by your machine shop guy.

Stroking the engine is entirely out of the question unless you have a huge pile of cash and a lot of expertise.

It is a 40+ year old bike. There are lots of things other than the engine that will need to be refurbished - bearings, brakes, carb, tires, electrical parts [generator, regulator, battery, circuit breakers, wiring, etc]. And more. Best to spend the first year getting all this stuff right. It will cost some $s along with the tools etc that you will need. Think about performance improvements after the basics are covered.

 

I visited the Twin Hills website ...
http://www.twinhillsiron.com/site.cfm/About-Us.cfm

They are not equipped to service or work on your IronHead. HD factory trained technicians are expert at servicing new bikes but have no idea about IronHeads - generators, mechanical regulators, cast iron engines, etc. These forums are filled with stories of good shops like this messing up IronHeads. This particular shop might be an exception, but it is unlikely.

You need to do all of the service work yourself. But find a machine shop that regularly works on vintage engines. If there is a local vintage motorcycle or auto club nearby that is a good place to start researching this topic. If there is none nearby you better choice is to pay the cost of shipping those parts to a well respected shop elsewhere. I can point you to a good place to ask.