Hi everyone, I’ve got a 2001 Honda Shadow VT750DC that’s been giving me a headache. It bogs down, sputters, and backfires at about half throttle. I’ve cleaned the carb multiple times and replaced the spark plugs, but it’s still acting up. Anyone else dealing with this?
Quick Response
Hey there, I feel your pain. I had the same issue with my Honda Shadow. After a lot of trial and error, replacing the pulse generator finally solved the problem for me.
Solutions that worked for users
| Solution | Users Who Found Success | Personal Experience | Estimated Cost (USD) | Time Needed (Minutes) |
|---|---|---|---|---|
| Replace Pulse Generator | 2 | Replaced the pulse generator and the timing issues were resolved. | $50-$100 | 30-60 |
| Check Idle Mixture Screws | 1 | Adjusted the idle mixture screws to about 2.0 turns from lightly seated. | $0 | 5-10 |
| Check Carb Diaphragms | 0 | Checked the condition of the carb diaphragms. | $0 | 5-10 |
| Check Spark Plug Caps and High Tension Leads | 0 | Checked the spark plug caps and high tension leads, especially after running the bike. | $0 | 5-10 |
| Check Carbs and Float Level | 0 | Ensured that the carbs are synced and that the float level is correct. | $0 | 5-10 |
Symptoms
- Bike bogs down and sputters at half throttle
- Backfires during acceleration
- Loses power at higher speeds
Possible Causes
- Faulty pulse generator
- Incorrect idle mixture
- Damaged carb diaphragms
- Weak spark strength
- Incorrect float level in carbs
Solutions that Worked
1. Replace Pulse Generator
What I Did:
Replaced the faulty pulse generator.
Outcome:
The bike stopped backfiring and losing power.
Personal Experience:
After replacing the pulse generator, the timing issues were resolved, and the bike ran smoothly.
Estimated Cost:
$50-$100
Time Needed:
30-60 minutes
Steps:
- Disconnect the bike’s battery for safety.
- Locate the pulse generator on your bike, usually near the crankshaft.
- Disconnect the electrical connector from the pulse generator.
- Remove the mounting bolts holding the old pulse generator.
- Install the new pulse generator and tighten the mounting bolts.
- Reconnect the electrical connector.
- Reconnect the bike’s battery and start the engine to test.
Expert Tip:
If you’ve tried multiple solutions and still face issues, consider checking the electrical components like the pulse generator. These components can significantly affect the bike’s performance and could be the root cause of the problem.
Handy Tip:
Before replacing the pulse generator, it’s a good idea to check its resistance with a multimeter. If the resistance is out of spec, it’s definitely time for a replacement.
2. Check Idle Mixture Screws
Steps:
- Locate the idle mixture screws on the carburetor.
- Use a flat-head screwdriver to turn the screws clockwise until lightly seated.
- Turn the screws counterclockwise about 2.0 turns from the lightly seated position.
Handy Tip:
If you’re not sure where the idle mixture screws are located, consult your bike’s service manual for guidance.
3. Check Carb Diaphragms
Steps:
- Remove the carburetor from the bike.
- Open the top cover of the carburetor to access the diaphragms.
- Inspect the diaphragms for any holes, tears, or deformities.
Handy Tip:
Use a flashlight to closely inspect the diaphragms. Even a small tear can cause issues.
4. Check Spark Plug Caps and High Tension Leads
Steps:
- Locate the spark plug caps and high tension leads.
- Inspect for any signs of wear, tear, or corrosion.
- Replace if necessary.
Handy Tip:
It’s a good idea to check these components especially after you’ve been running the bike for a while, as issues may not be apparent when the bike is cold.
5. Check Carbs and Float Level
Steps:
- Remove the carburetor bowls.
- Measure the float level using a ruler.
- Adjust the float level if it’s not within the specifications mentioned in the service manual.
Handy Tip:
Incorrect float levels can cause the bike to run rich or lean, leading to various issues including backfiring.
Bike Models Where This Worked
- 2001 Honda Shadow VT750DC