Care and Feeding Instructions for Ironhead Sportsters

Unique Essential Tips for Ironhead Sportsters

The Ironhead Sportster has enjoyed a bit of a come back in popularity as it is a pretty unique bike, although fickle at times if you don't know how to maintain one. Believe me, if you are riding one a lot, they need attention. That's how I ended up becoming a Harley mechanic. I went through Sportster engines like people go through socks. Not to mention I liked everything else, like the suspension and brakes to work. I liked to go fast. So I know them inside and out pretty well. That was from just what I owned, a 1968 XLCH and two 1965 XLCH's. Then there was all the shit I had to work on.

1973 xlch sportster engine rebuilt

What should you expect out of your Ironhead Sportster?

Living in Texas I can tell you Texas is a big state for a Sportster if you plan on doing any serious riding. Balls out on a healthy well built Sportster is about 120mph. They don't last long at that speed, especially if it's 100 degrees outside. Traffic on the highways around here rolls at about 80mph. A Sportster can cruise comfortably at about 65 to 70mph, if properly geared right.

Sometimes you have a good Sportster and it does well and sometimes you end up with a constantly broken down money pit. Theoretically you should have a good one if everything in the engine is within specification and you take good care of it.

FUN FACT: Most cheap Ironhead Sportsters for sale are money pits that have been used and abused and are in need of much attention. So that $1000 dollar deal you got on that bike ends up needing a $3500.00 rebuild if you actually plan on riding it.

FUN FACT #2 It's entirely possible to pay good money for a good looking money pit. It's best to know something about what you are buying, and even then things might not be as they seem.

What oil to run in your Sportster.

For the engine oil:

You should be running straight 50w when temperatures are 70 degrees or below and straight 70w when it's 70 degrees and above. If you live and ride in the cold weather like 40 degrees and less, 20w50 will work just fine.

Winter Riding Tip:  run about 1/2 to a quart low, so that the oil warms up faster. If you use your bike to go across town, or real short trips, a quart low is good. If your going to work every day and it's between 30 and 60 miles one way a 1/2 quart is good. Warm oil does it's job much better than cold oil. Also the oil should get hot enough to evaporate any condensation (water) that accumulates from temperature swings.

Many early Sportsters didn't come with an oil filter. If your bike doesn't have an oil filter you have best be changing that oil every 1500 miles religiously. I don't recommend running anything without an oil filter.

An oil cooler is another must have item if you expect the motor to last. It won't do you any good if your sitting in traffic and not moving, but it does help a lot when you are moving. When oil breaks down because it has reached it's break down temperature (usually around 250 degrees for regular, and 280 degrees for synthetic ) Bad Things Happen. If you think your oil has been over heated, You need to change it out immediately. It will no longer do what it is supposed to be doing. See article on oil.

For the Transmission / Primary:


It does not use much oil and it should be changed regularly. Keep the Primary Chain properly adjusted. With engine COLD it should have 5/8" to 7/8" slack and HOT 3/8" to 5/8". Be sure to inspect primary shoe for wear and to see that it is held in place tight on 1952 to 1976 models.

For 1971 and later, with a wet clutch, a quart of 20w50 motor oil works well. No special Harley yuppie juice required. If you have a clutch that likes to drag make up a quart of 1/2 20w50 and half ATF. ( Automatic Transmission Fluid). ATF works well to keep the clutches clean and helps them release better.

For 1970 and earlier, with a DRY clutch use 3/4 of a quart of either straight 50w or straight 70w depending on temperature. The heavier oil is used to help keep the dry clutch dry as they are prone to getting wet through the seals because all the clutch shells rock, especially the single row bearing shells.

If you run your early clutch wet, using Barnett wet or dry plates (Highly Recommended) you would use a quart of 20w50, just like 1971 and up.


NEWS FLASH --> If you own an Ironhead Sportster YOU WILL BE WORKING ON IT.

Maintenance is of the utmost importance.


Things you should really pay attention to when servicing your Ironhead Sportster.

  • Valve adjustment.

    The book tells you to check the adjustment at 500, 1000 and then every 2000 miles. Normally after the initial 2 break-in checks, I check them at every oil change, which is usually 3000 miles providing you are running a oil filter. Check the adjustment when the engine is cold and the tappet you are working on is at the lowest point. The pushrod should spin freely, with no up and down movement. After adjusting it roll the engine through and recheck your work, then move on to the next one.

  • NOTE --> Do Not get too fussy with adjustment.

    The cylinders and heads are cast iron and the pushrods are aluminium. The pushrod will expand more than the cylinder when hot and it is possible to adjust them too tightly. When this happens the engine will be hard to start hot and you stand the chance of burning a valve from an adjustment that is too tight and holding the valve(s) open. Too loose is better than too tight when in doubt.

  • Ignition System.

    Do not over look the ignition system especially if yours uses advance weights. All point systems use advance weights and some electronic systems, like Dyna S  also use weights. The weights should be inspected and lubed periodically depending on how much riding you do. See maintenance guide.

  • Carburetor and Intake.

    The carb and air filter assembly should be well supported so that the intake manifold can seal properly and not leak. Intake leaks can cause things like poor running and even put a hole in a piston from lean running condition. 1978 and later Ironheads with the "rubber band" type intake manifold and heads, should have the intake seals replaced once a year. These are notorious for cracking and leaking.

  • Kick Starter.

    Sportster kick starters are known for bustin' knee caps. That is a fact, Jack. 1971 and up have a better set of kick ratchets then the earlier 900cc models. They have a gear with a bushing and the bushing should be inspected if the kicker has a tendency to slip through, as that bushing wears. It's normally common to just replace the whole sliding gear with bushing. If it has been slipping for a while it's probably time to change out the ratchet on the back of the clutch hub too.

    Also important is the kicker shaft, it should be straight and in good shape and the nut for big gear on it, inside the primary, should be tight. Carefully inspect the kicker / sprocket cover to see that the support bushing is in good shape and greased. Look for cracks around the bushing and by the bolts that hold the cover on the engine case. Also be sure that the bolts are in good shape and the holes they are threaded into aren't stripped out or damaged.

  • Drive Chain and Sprockets.

    Ironheads are known for having the nut on the front transmission sprocket come loose. Chains are often neglected. Rear drum sprockets are known for shearing off the rivets, leaving you stuck.

  • Rear Brake.

    This is another area of problems and neglect. If riding all the time, the rear wheel should be pulled once or twice a year and the brake dust cleaned out of the rear brake drum and parts. The pads should be checked for wear and replaced when necessary.

    A common problem is when the shoes rub against the back of the drum. This is noticeable by an obvious wear mark. If this is the case a shim can be added between the 2 wheel bearings to push the brake backing plate out and move the shoes away from the drum so they do not rub. Clean the brake shoe cam and apply a light coat of grease to it and also grease the shaft for the brake shoe cam.

    While the rear wheel is off check the wheel bearings to see they are in good shape. It would also be a good time to clean the chain grease off the sprocket and inspect the rivets that fasten the sprocket to drum, and wear of the sprocket teeth.

  • Swingarm.

    Many times I find the swingarm to be loose and bearings well over due for replacement. It's a big job that's not really a whole lot of fun, but a swingarm should be pulled every few years and the bearings inspected and greased or replaced. I have had to spend hours beating out the bolt that holds the swingarm on from it being rusted in place from neglect. That just makes a not so fun job no fun at all, because if the bolt has to be severely beaten out, the engine will have to be removed from the frame as the primary drive part of the engine case is in the way.

  • Shocks.

    Many times for what ever reason, your ironhead will need a pair of shocks. The shocks are 14 &1/4" eye to eye and some have 5/8" mount holes and later ones have 1/2" mount holes. It is hard to find a good pair "laying around" as most Harley shocks are between 12" and 13" long and will not work on your Ironhead.