S&S 124 Problems – Harley’s Engine That’s Made to Last

Harley-Davidson is such an iconic brand and there are only a handful of cruiser-type bike manufacturers who pose a legitimate threat to its position in its niche within the market. Its bikes are known for their signature retro street styling backed by incredible engine performance.

Well aware of Harley's almost unrivaled appeal, Illinois-based S&S Cycle, has anchored its business model with the Wisconsin-based cruiser manufacturer. So, for those who are not contented with what the stock engine Harley offers, S&S surely has them covered.

One of the key offerings of the brand is the S&S 124, which has had its own share of defenders and detractors over the years. That's because it's such a mixed bag when it comes to reviews and reports as some say that it is made to last a long time while others said they had their share of regrets about getting it.

Most Common Problems Found in the S&S 124 and Their Solutions

In this article, we will take a look at the most common problems that you can expect when you swap your Harley engine with an S&S 124. All the information here has been derived from customer reviews, forums, and reports dedicated to the engine or Harley bikes.

1. Piston Slapping

There have been numerous complaints about piston slapping problems in S&S 124-equipped Harley bikes. The most common symptom of this issue is a knocking or rattling noise coming from the engine, which gets worse as the engine speed increases. The symptoms are often accompanied by loss of power and decreased fuel economy.

According to mechanics who are very much familiar with the issue, this is often because of the improper installation of the crate engine or problem with the assembly itself. Although S&S engines are undeniably sturdy, it is possible that this is also due to premature wear on some of its components either by design or irresponsible use of the bike itself on the part of the owner.

There are a few ways to diagnose the piston slap issue. One is to listen to the engine with a stethoscope, which will amplify the sound of the knocking. Another way is to remove the spark plugs and inspect them for damage caused by the reverberations caused by the erratic pistons.

Finally, a compression test can be done to check for pressure changes in the cylinders that can indicate piston slap.

There are a few possible solutions for fixing piston slap. If you are sure that the engine has been installed properly during the upgrade process. One solution is to install thicker piston rings, which will help reduce the amount of movement of the pistons.

Another is to install a set of shock absorbers on the pistons, which will help absorb some of the vibrations caused by the slapping. Finally, the engine can be rebuilt with larger cylinders and pistons that have more clearance, which will help prevent the problem from happening again.

All these definitely require the expertise of an experienced mechanic. So, if you are experiencing this issue, don't hesitate to bring your motorcycle to your trusted auto repair shop right away.

2. Blow-by

The most common symptom of a blow-by problem in an S&S 124 engine for a Harley bike is excessive oil consumption. This can be triggered by a number of factors, including worn piston rings, damaged cylinder walls, or a clogged crankcase ventilation system.

To diagnose the problem, check the oil level first. If it is low, then you may have a blow-by issue. Next, inspect the air filter to see if it is excessively dirty. This can be an indication that a blow-by is occurring. Finally, check the crankcase ventilation system to ensure it is not blocked.

There are several possible solutions to a blow-by problem. First, you can try replacing the piston rings. This may solve the problem if they are worn or damaged. Second, you can try repairing the cylinder walls.

This may be necessary if they are damaged. Finally, you can try cleaning or replacing the crankcase ventilation system. This may be a necessity if it is blocked.

If you are having trouble diagnosing or solving a blow-by problem, then you should consult a qualified mechanic immediately.

3. Check Engine Light On

This may happen just after you have swapped your Harley engine with an S&S 124 or it may occur after a long run with your engine. There are a few reasons why the check engine light may come on after installing an S&S 124 engine in a Harley bike.

One possibility is that there may be something wrong with the installation itself. Another likelihood is that the new engine may be not compatible with the rest of the bike's components. Lastly, it is also probable that the check engine light is simply a result of a faulty sensor or other components of the engine.

If you suspect that the check engine light is due to an installation issue, the first thing you should do is check all of the connections and make sure that everything is tight and secure. If you find that something is loose or not connected properly, tighten it up or reconnect it and see if that fixes the problem.

If the check engine light is still on after checking the installation, it's time to consult a professional mechanic or Harley dealer to diagnose the issue.

Although S&S has almost perfected its craft for Harley bikes, we still cannot dismiss compatibility issues as the cause of the check engine light. One possibility is that the engine you got may be faulty from the get-go.

The best course of action for this is to consult with an expert. A professional mechanic or S&S dealer will be able to tell you for sure whether or not the new engine is working well with your bike and can help you make any necessary adjustments or replacement if you got a product with a factory defect.

Finally, if you suspect that the check engine light is simply a result of a faulty component of the new engine, it's important to get the engine checked out as soon as possible. A professional mechanic or S&S dealer will be able to diagnose the problem and make any necessary repairs or replacements.

In most cases, a simple flashing or resetting with the engine management system will get the light to turn off and keep it from coming back on again. Meanwhile, if the sensors, wiring, or other electrical components of your motorcycle are already showing signs of damage, they may have to be replaced.

However, in some cases where more serious engine damage may have occurred, you may need to replace the entire engine or have it rebuilt.

No matter what the cause of the persistent check engine light is, it's important to get it inspected by a pro as soon as possible to avoid further damage to your bike.

Other Things to Consider When Swapping Your Harley Engine

In addition to the known problems of the S&S 124 engines, there are some important things that you should also keep in mind if you are replacing your Harley engine with an aftermarket product. These are:

1. It's Illegal to Use or Buy the S&S 124 Engine in California

For some reason, dealers of S&S 124 engines always come with a warning for buyers that the power unit is illegal to be used in California. Likewise, we cannot see any shops selling the engine in the said state as it is apparently illegal to sell it there, too.

These are simply because the strict regulations of the state do not consider bikes carrying the engine as street-legal and emission-compliant. There's really no other way around this, so just don't bring your bike there.

Even if you're outside California, you should also check with the emission laws and other ordinances in your area if it's safe to ride your S&S 124-fitted Harley there. If required, you may need to upgrade your catalytic converter to complement your new engine.

The best course of action for this is to check with someone who has legal expertise in your state, particularly someone who specializes in traffic and emission laws.

2. Loss of Warranty with Harley

Another inevitable trade-off of shifting to an S&S 124 engine is that you are certain to lose your warranty or other privileges with your Harley dealership. So, if you just bought a brand-new Harley bike, this is something that you should think about carefully.

However, if you are well aware of the risks, no one is really stopping you from using a more powerful engine for your bike.

Should You Swap Your Harley Engine with the S&S 124?

As long as you are not breaking state laws, you are well aware of the potential risks of doing so, and you have an expert mechanic by your side, then, by all means, upgrade your engine to the S&S 124 if that will make you enjoy your bike more.

Although there are known issues with the S&S 124 engine, that does not mean that you can't avoid them altogether. With proper care and periodic maintenance, you can dodge these potential issues. If you're lucky enough, you can emulate the success of some owners who have claimed to have taken their engine up to 100,000 miles before requiring major repairs or parts replacements.

Lastly, you should bring your cruiser to a mechanic right away if you notice anything unusual with its performance. This will surely prevent the problem from getting out of hand and transforming into a more expensive issue for your bike along the way.