The Suzuki RM 85 is a popular motocross bike among young riders looking to race or ride on a closed dirt track.
Like any other motocross dirt bike, the Suzuki RM85 is prone to some problems and issues that impact its performance and reliability.
This article examines some of the most common problems with the Suzuki RM85, what causes them, and how to fix them.
Whether you’re a new rider looking for used models or an experienced rider looking for a brand-new motocross bike, knowing how to troubleshoot these problems will save you time, money, and frustration.
Table of Contents
1. Spark Plugs Foul Easily
One of the common problems that Suzuki RM85 owners report facing is easily-fouled spark plugs. Fouled spark plugs can cause the bike to stall or run poorly and requires more frequent spark plug replacements.
Fouling is when the spark plugs get dirty or coated with carbon, oil, or fuel and lose their ability to ignite the air-fuel mixture to power your engine.
One Suzuki RM85 rider described this problem as follows: “[My son] ran it the first day there with no issues. The second day he ran it during the morning, and all was fine. By the second ride, he said he noticed a loss of rpm in 1st and 2nd gear but seemed fine in 3rd. He was trail riding and went into a hill climb in 3rd and dropped to 2nd because it was bogging up the hill in 3rd, and as soon as he hit 2nd, the bike died. We checked the spark plug, and it was fouled.”
Your Suzuki RM85 might be burning through spark plugs faster than expected due to several possible factors:
- Rich jetting: If the carburetor is flooding the engine with fuel, overpowering the air intake can cause undue spark plug wear.
- Insufficient warm-up: Not letting the engine reach its optimal operating temperature before hitting the road could cause premature spark plug wear.
- Low RPM riding: If you’re not revving your engine high enough, excess fuel or oil may not burn off efficiently, leading to spark plug fouling.
To counter spark plug fouling on your Suzuki RM85, consider these potential remedies:
- Carburetor Adjustment: Consider tuning your carburetor to achieve a leaner air-fuel ratio, which can help prevent spark plug fouling.
- High-Heat Spark Plugs: These plugs have a higher heat tolerance and are more resistant to fouling, making them a proper replacement.
- Oil Type and Ratio Modification: Changing the type of oil you use or adjusting the oil ratio can influence how much oil enters the combustion chamber, affecting spark plug health.
- Proper Engine Warm-Up: Ensure you allow your engine to properly warm up before you start riding.
2. Power Valve Issues
Another common problem with the Suzuki RM 85 is issues with its power valve.
This crucial component regulates the exhaust port timing in the bike’s two-stroke engine, adjusting power output based on RPMs. Governed by a series of interlinked parts like the linkage, governor gear, and rod, these elements shift in sync with your engine speed.
One rider shared their struggle with such an issue, saying: “I am having a few problems with my rm85 #1- it almost feels like it is running on choke in first and second gear. I believe this is due to the fact that a.) the plastic linkage on my power valve is obliterated. b.) I believe my governor gear is also bead because whenever I pull off the power valve cover, the rod going into the case on the gear won’t move up or down when revved, but it is very easy to move by hand. Almost feels like it isn’t attached to anything.”
Power valve issues on a Suzuki RM85 can stem from various causes:
- A broken linkage could mean your power valve isn’t effectively connected to the governor gear, impacting its ability to open or close as it should.
- A worn governor gear could prevent the power valve from syncing with the engine speed, disrupting the correct adjustment of the exhaust port timing.
- A stuck rod could cause the power valve to jam, restricting its capacity to regulate the exhaust port area.
That said, there are some practical solutions for these issues, such as:
- Consider replacing faulty elements like the linkage, governor gear, or rod with new parts.
- Ensure your power valve assembly is clean and free from carbon deposits or dirt that could lead to sticking.
- Regularly lubricate the power valve components for smooth operation.
By taking these steps, you’ll be on your way to resolving or avoiding power valve problems, enhancing the performance and power delivery of your RM85.
3. Leaking Coolant
Another common issue for Suzuki RM85 owners is problematic coolant leakage. The coolant, an essential fluid for the radiator’s cooling process, circulates within the engine and radiator, preventing overheating.
This coolant, however, can escape through various parts, such as the hoses, the radiator cap, the water pump, or even the cylinder head.
One rider shared their experience with this issue: “I have a mysterious leak of coolant somewhere around my power valve- I’m thinking it could be the o ring on the cylinder head is bad.”
- While the power valve issue mentioned in the quote above and in the previous section is a possible culprit, the root causes of coolant leakage on an RM85 can vary:
- A damaged O-ring or gasket may break the seal between the cylinder head and the power valve or the cylinder, resulting in coolant seepage.
- A loose or cracked hose connecting the radiator to the engine could be the culprit if it isn’t adequately tightened or has sprung a leak.
- An ineffective radiator cap might not seal the radiator properly, unnecessarily releasing coolant.
- A malfunctioning water pump, which circulates the coolant through the system, might be broken, causing coolant leaks.
Luckily, solutions to these coolant leakage problems are straightforward:
- Replace the damaged O-ring or gasket with a new one.
- Tighten the loose hose or replace a cracked one with a new one.
- Swap out the faulty radiator cap with a new one.
- Repair or replace the damaged water pump with a new one.
By adhering to these tips, you can tackle or prevent coolant leaks, ensuring your RM85’s engine stays cool and runs smoothly.
4. Faulty Throttle
One of the problems Suzuki RM85 owners may encounter is a troublesome throttle. Your RM85’s throttle regulates the mix of air and fuel entering the engine and can sometimes present problems like bogging, hesitation, or sticking.
One rider encapsulated this issue, saying: “The throttle feels very sluggish when I turn it in about the first 1/4. When I try to flick it all the way, it seems as if it will bog out for a split second, but it picks itself back up.”
The root of the faulty throttle issue on a Suzuki RM85 can stem from various factors:
- A dirty or misaligned throttle cable can cause friction or binding, inhibiting smooth operation.
- A clogged or maladjusted carburetor can lead to suboptimal fuel delivery or air-fuel mix.
- Air leaks in the intake system can disrupt the air-fuel ratio, affecting performance.
To resolve these throttle issues, you can:
- Clean, lubricate, and correctly route the throttle cable.
- Clean, tune, and adjust the carburetor components, such as the jets, needle, and air screw.
- Inspect and seal or replace any leaks or cracks in the intake manifold or reed valve.
Follow these tips to restore or enhance your RM85’s throttle responsiveness and overall performance.
5. Carburetor Problems
Another prevalent issue for Suzuki RM85 owners is carburetor problems. The carburetor, which mixes air and fuel for the engine, can face a range of issues, such as clogging, gumming, or maladjustment.
A rider recounted their struggle with this issue, stating:
“I have a 2005 rm85l. It has been sitting for about two years. I cleaned out all the old gas from the tank and carb. I put new gas in it with oil mixed at 32:1. It will start but only run with the choke on. As soon as I take the choke off, it dies.”
Potential causes for these carburetor problems can be:
- Bad gas can lead to poor combustion or corrosion.
- Dirt or debris in the tank or carburetor can obstruct fuel delivery by blocking the jets, needles, or passages.
- Incorrect storage can cause fuel evaporation or gumming in the carburetor.
To combat these carburetor issues:
- Drain and replace old gas; add a fuel stabilizer for improved combustion.
- Clean the tank and carburetor to remove any dirt or debris.
- Prepare your bike for long-term storage by draining the gas or running it dry.
These tips will help to resolve or prevent carburetor problems, ensuring your RM85’s engine runs with optimal smoothness.
6. Suspension Failure
A common snag that Suzuki RM85 owners might experience is suspension failure. The suspension system, a crucial feature that absorbs shocks and bumps from the terrain, can face issues such as leaks, bottoming out, or harshness, impacting your comfort and control.
One rider shared their frustration with this issue:
“I have a 2007 rm85l, and I weigh 140 pounds. The suspension is way too soft for me, and it bottoms out on every jump. It also feels very bouncy and harsh on the small bumps.”
Suspension issues on a Suzuki RM85 can be attributed to various factors:
- Damaged seals might lead to oil leaks, air entry in the forks, or shock absorbers.
- Worn-out springs can cause the suspension to be excessively soft or bottom out.
- Old, dirty, or low oil in the suspension system can make it harsh or inconsistent.
To address these suspension issues:
- Service your forks and shocks, replacing seals, oil, and bushings as necessary.
- Upgrade your springs to better match your weight and riding style.
- Fine-tune your compression and rebound damping to suit your terrain and riding preferences.
Following these tips should help rectify or avoid suspension issues, enhancing your RM85’s handling and comfort.
7. No Electric Start
One recurring issue Suzuki RM85 owners often grapple with is the absence of an electric start. Unlike some other bikes, the RM85 does not feature this convenience, requiring the rider to kick-start their engine manually instead.
This lack of an electric start can pose challenges, especially in less-than-ideal conditions or for younger, less experienced riders.
It’s not uncommon for motocross bikes to be kickstart only, as it requires less maintenance, equipment, and electronics and shaves off weight.
That said, the absence of an electric start on the RM85 might be an oversight considering its target demographic.
Younger riders, who are still learning the basics, may find the physical effort of kick-starting their Suzuki engine daunting, especially when the engine is cold or flooded.
While retrofitting an electric start onto the RM85 isn’t a practical option, choosing a different bike with an electric start feature might be worthwhile if this issue significantly impacts your riding experience.
- Learning and practicing effective kick-starting techniques can help make the process less daunting and more efficient.
- Regular maintenance can ensure that the engine starts more efficiently, reducing the number of kick-start attempts needed.
By adopting these strategies, riders can either adapt to the RM85’s lack of an electric start or consider alternatives that might better suit their needs, making their riding experience more enjoyable.
What Are the Pros and Cons of the Suzuki RM85?
- Powerful Two-Stroke Engine
- Adjustable Power Valve System
- Lightweight Design
- Showa suspension
- Efficient Braking System
- Spark Plugs Foul Easily
- Power Valve Issues
- Leaking Coolant
- Faulty Throttle
- Carburetor Problems
- Suspension Failure
- No Electric Start
What Do the Reviews Say?
“The 2020 Suzuki RM85 is a kid’s motocrosser. Although it does have approachable power from the 85cc single-cylinder two-stroke engine, its six-speed transmission makes it more appropriate for kids who have already mastered the art of shifting.” – Cycle World.
“The 2023 RM85 continues to carry on the powerful tradition of racing excellence in the Suzuki motocross family. The reliable two-stroke engine produces smooth power at any rpm, emphasizing low- to mid-range performance. Just like its larger RM-Z cousins, the RM85 delivers class-leading handling for experienced racers and rookie riders alike.” – Total Motorcycle.
“The Suzuki RM85 comes with a powerful peppy two-stroke engine that offers good low and midrange performance. It offers smooth power delivery across the entire rev band. The RM85 is a good bike for beginners looking to enter the world of dirt track competition.” – Mototech India.
“The Suzuki RM85L goes best when you ride it hard. If you let the revs drop too much, it can bog, but if you keep it revving, it goes quite all right. The suspension kicked around a bit, but after slowing the rebound damping and getting the sag height set right, it handled much better.” – Australasian Dirt Bike Magazine.
What’s the Resale Value of a Suzuki RM85?
|Used Listing Price
What Are Some Alternative Models?
|KTM 85 SX 19/16
|Husqvarna TC 85 19/16
|TM MX 85