7 Common Problems with the Honda CRF50F (Explained)

The Honda CRF50F is a reliable and affordable mini dirt bike for kids to learn.

Although this little ripper is celebrated for its durability, some common mishaps can cause issues if owners aren’t aware.

This article covers issues with the CRF50F, including troubleshooting tips along the way.

Exhaust Leaks

Some Honda CRF50F riders report issues with the exhaust system. Exhaust leaks are typically caused by loose bolts or gaskets, not the exhaust system, or a loose, cracked, or damaged pipe.  

“I recently put a new top end in my 2012 CRF50.  I did so because it lost power and had a few hundred hours on it. I bought an OEM piston, rings, etc., and put it all together.   After I finished putting it all back together, it had the SAME issues. NO POWER.  I did a leak-down test, which shows leaking through the exhaust.” Thumpertalk.com

“Did you do a valve adjustment using .002″ for intake and .003″ for exhaust? If the valves are tight, you will have compression seeping past valves that aren’t closing completely.” Thumpertalk.com

To troubleshoot an exhaust leak on a Honda CRF50F:

  • Have a pro examine your valves, ensuring the valve clearance is adjusted per the manual guidelines.
  • Inspect your exhaust gaskets for cracks and wear that might be letting wear out, replacing your gaskets as needed.
  • Check and tighten all exhaust bolts as needed.
  • Inspect your exhaust pipe for cracks and damage from scraping, replacing a damaged pipe to prevent leaking and backfiring.

Hard to Start

Riders report the Honda CRF50F has trouble starting in certain conditions. Starting problems are often caused by blocked pilot jets, poorly adjusted valves, or weak/worn spark plugs.

To remedy starting issues on a Honda CRF50F:

  • Inspect your Honda’s pilot jets, cleaning and replacing them as needed.
  • Your CRF50F’s valves should be set at (intake: 0.002″, exhaust: 0.003; have a pro examine your valve setting, adjusting them as needed.
  • Inspect your spark plugs, replacing them if worn or burnt out.

Rough Idle

Honda CRF50F owners report that their bikes develop rough idles, which make it difficult for their kids to ride. Rough idle on CRF50Fs are usually caused by clogged or improperly adjusted idle jets, air leaks in the intake system, or incorrectly adjusted valves.

“I just bought a used CRF50 for my daughter. I replaced the carburetor and fuel tank with Petcock OEM, and it is running pretty well. I’m experiencing a few things:

  1. On occasion, I’ll ride around with the bike without issues, but when I come to a stop, the bike will want to die slowly. I tried adjusting the idle, but for some reason, it’s specific to coming to a stop while riding.
  2. Sometimes, in idle, the bike goes higher into the RPM, then goes down and continues that pattern. When putting it into gear, it jerks pretty bad. If put into gear at a random high RPM moment, the bike’s front end just jerks up even when I’m on it.
  3. Jerky when kicked into first. When messing with idle screws, I can get it to be not so bad, but seeing if I can eliminate it totally. At random, though, problem 2 occurs with a high RPM.

My daughter wants to ride the bike real bad but the jerky shifting is getting her a little intimidated.” Thumpertalk.com

  • Clean your CRF50F’s idle jet, ensuring fuel flows freely. If the jet is beyond repair, replace it.
  • Inspect your air intake manifold, carburetor, and intake system gaskets for any weak points that may be releasing air—seal any air leaks you find.
  • Have a mechanic verify your valve clearance settings (intake: 0.002″, exhaust: 0.003

Engine Bogging at Mid RPMs

The Honda CRF50F’s engine may bog at mid-range RPMS due to an improper air-fuel ratio. A clogged air filter, improper ignition timing, a restricted carb, and exhaust can all cause bogging on a CRF50F.

“A couple of days ago, my son was riding his 2015 Honda 50f, and all of a sudden, it bogged out. It will idle fine and take off fine but will only get into about mid rpm’s and won’t go any higher. It will hit the rev limiter in neutral but put it in gear, and it will not. I took the carb off and cleaned all the jets with carb clean. I took the Pitcock out, thinking it was starving for fuel, but nothing. I also put a new spark plug in.” Thumpertalk.com

Check the air filter and exhaust for blockages.

Adjust the carburetor settings, ensuring the jets are clean and the float level is correct.

Inspect the ignition timing.

Replace or flash the Electronic Control Unit (ECU).

Backfiring and Engine Sputtering

Honda CRF50F owners sometimes report backfiring and engine sputtering caused by improper air/fuel ratios or leaking exhaust system joints. Worn spark plugs, ignition coils, or wiring can also cause backfiring on a CFR50F.

“I got my son his first bike, a 2007 CRF50F, and he’s been all about it after getting off to a kind of rough start… he started having issues where it would backfire a bunch and then die. When it would die, it would act like it wasn’t getting any fuel when we tried to restart it despite him still having about 3/4 tank of gas…” Thumpertalk.com

“My son’s bike was having sputtering and backfiring issues. I cleaned the carb and replaced the jets, but they didn’t fix it. I removed the intake and found that the gasket carb insulator and o-ring were shot. Replaced those and fixed the issue.” Thumpertalk.com

  • Inspect your ignition system, changing your spark plugs if necessary.
  • Tune your CRF50F’s carburetor, adjusting the air/fuel screw according to the manual.
  • Check all exhaust joints are connected tightly and sealed.
  • Examine your exhaust system’s gaskets to make sure they’re not leaking.

Carburetor Problems

Like all dirt bikes, the Honda CRF50F needs to have its carb cleaned and adjusted periodically. Poorly adjusted carbs are prone to failure due to worn needle valves and floats, bad gaskets, seals, or clogged jets.  Inspect and adjust the carb’s air: fuel screw to maintain a proper air: fuel mix.

“I got him a 2007 CRF50F, and when I went to look at it, it started right up. The first kick was right, and I was able to ride it around the block. It went through all three gears just fine. When looking at it, I didn’t check the crankcase to see if it was already warmed up. We took it out camping a week or two after I got it, and it started right up on the first or second kick; I rode it again, and it seemed fine… Yesterday, I got to take my son riding; his bike started first kick, with no choke. I revved it up high and then let it sit so it could warm up. I tried putting on the choke, but that just made it bog down like it was going to die, so I left the choke off. I put the bike in 2nd gear and sent my son toward the field I wanted him to ride in.” Thumpertalk.com

  • Inspect, clean, and adjust your CRF50F’s carburetor per the service intervals outlined in the owner’s manual.
  • Adjust the air: fuel screw to maintain engine performance.
  • Inspect your carb’s needle valve, float, and gaskets, replacing worn or damaged parts.
  • Clean your carb jets and passages.
  • Purchase a carburetor rebuild kit to keep it tuned and in ideal condition.

Air Filter Hard to Clean

Some Honda CRF50F riders report that the bike’s stock air filter is a pain to clean due to its foam-and-oil design, intended to trap dirt more effectively. While cleaning the CRF50F’s air filter is more involved than on other dirt bike models, there’s no doubt it lets less dirt through than a typical dirt bike air box.

Other riders upgrade their Honda CRF50F’s air filter to a design that doesn’t require oil, only to experience running and starting issues due to frequent clogs.

“I bought my grandson a CRF50 that he loves.  It was a used bike, but it was in great condition. I changed the oil and new plug and cleaned the air filter, which was a pain in the behind.  I want to get an aftermarket filter that’s easier to work on.  He just rides the bike around the house in the grass so I was wondering if anyone makes one that I can just blow with air and not mess with the oil? Seems all the ones I’ve found use the oil.” Thumpertalk.com

“Running the stock air filter is your best bet. Aftermarket pod filters without the airbox allow water to be drawn in if the bike is ridden through puddles. The stock foam filter is easy to clean; a little kerosene or fuel to rinse it out, then squeeze some 30+wt through it and toss it back on.” Thumpertalk.com

  • Consider an aftermarket air filter like a UNI—known for being user-friendly while splitting the difference between ease of maintenance and engine protection.
  • Keep up with air filter cleaning and maintenance, inspecting it before and after hard rides in dusty conditions.
  • Whichever filter you use, follow the complete eminence guidelines for that particular type of filter.
  • Using oil in foam filters is crucial for trapping fine particles.
  • While foam-and-oil style filters are more involved in service, they do an impressive job of managing dirt intrusion compared to other airbox filter styles.

What Are the Pros and Cons of the Honda CRF50F?

  • Keyed ignition allows parents to supervise riding
  • Easy maintenance
  • Reliable 50cc four-stroke motor
  • Automatic clutch for beginner riders
  • Lightweight
  • Compact
  • Easy to ride
  • Predictable braking


  • Small bike—made for children to learn on
  • Lacks power for kids to grow into
  • Not for learning to race on—more of a casual trail bike.

What Are Some Alternative Models?

Make/Model MSRP (New) in USD MPG (Approx.)
Honda CRF50F $1,649 74
Yamaha TT-R50E* $1,749 69
Kawasaki KLX110 $2,349 68
Suzuki DR-Z50 $1,799 72
KTM 50 SX Mini $3,999 70

What’s the Resale Value of a Honda CRF50F?

YearMileageUsed Listing Price


Used Honda CRF50F motorcycles for sale – MotoHunt

Honda CRF50 Review (Speed, Height, Price) – Good? (braapacademy.com)

2022 Honda CRF50F Review and Specs | Kids Dirt Bike Hub

CRF50 with UNI Air Filter – YouTube


  • Ian Sawyer

    Growing up with a father who was a mechanic I had an appreciation for cars and motorcycles from an early age. I shared my first bike with my brother that had little more than a 40cc engine but it opened up a world of excitement for me, I was hooked. As I grew older I progressed onto bigger bikes and...

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