How to Adjust The idle on a Honda TRX 250 (TRX250)?
How do I alter the engine idle speed on a Honda TRX 250? My 2005 Honda TRX250EX idles too slowly in neutral. It runs so slow in neutral that when I put it into gear it stalls.
I want to tune the carburetor to increase idle speed but I am not even sure where the idle speed screw is located.
How do you adjust the idle on a Honda TRX 250?
Answers ( 3 )
First tune-up the engine. You cannot properly adjust engine idle speed until you’ve performed all of the required maintenance.
Be certain to clean or replace the air filter element. Replace the spark plug if it is worn. Spark plug gap should be 0.8 – 0.9 mm (0.03 to 0.04 in).
The standard spark plug is NGK DPR8EA-9. Use NGK DPR7EA-9 if you live in a climate with a temperature Below 5°C/41° F. Use NGK DPR9EA-9 if you do mostly high speed riding.
Also, change the engine oil and filter. Be certain to check cylinder compression pressure. It’s always a good idea to check valve clearance, too. The 4-wheeler might run poorly because of issues not related to setting the idle.
How to Adjust Engine Idle Speed
1. Ride the all-terrain vehicle for 10 minutes.
2. The engine must reach normal operating temperature to accurately set idle.
3. Remove the right side cover, if applicable.
4. Connect the tachometer to the spark plug wire. Get this https://amzn.to/3gliojM tachometer, it works great.
Use a tachometer to set idle.
5. Turn the throttle stop screw in either direction until the desired rpm is achieved.
6. Idle speed RPM for your vehicle is 1400 ± 100 rpm.
At idle speed, the engine should run smooth and balanced. If the idle speed is too low it will run irregular and bumpy. It also decreases fuel mileage.
A high idle speed will cause harsh engagement in drive and require more brake effort to hold the ATV in place. Excessive idle can damage the engine.
I need to set the idle on my Honda TRX250TE Recon. Do I use these same idle speed adjustment instructions?
These instructions apply to 1985 to 2011 models. However, spark plug type and gap are different for 2004 and earlier models.