You are here:

Motorcycle Repair/trouble shoot motorcycle

Advertisement


Question
I have a 2001 yamaha vstar 1100 that the front cylinder is not working and it is back firing

Answer
Hi Rod,

Most of the time a cylinder that backfires is running lean/not getting enough fuel.

The causes can be many, starting with bad spark plugs, plugged carb jets,
and other gremlins.

I would first check the spark plug and see if the front cylinder has a wet or a dry plug.
If it is wet you might have spark problems. If the plug is dry then you
can try some fuel system cleaner like seafoam in it or clean the carb.

Check that your battery is holding over 12.3 volts and charging over 14 volts dc.

Make sure carb mount is not leaking vacuum or air into the intake leaning the fuel charge.

Check plug cap or try swapping them.

If your compression is low on that cylinder then the valves might need adjustment.

Carbs must be soaked in carb cleaner, yamaha brand preferred as it is safer.
All small passageways and jets must be checked carefully.

A poor battery can result in a weak spark as well as the plug, cap, cables.

Start by reading the plug and see what it tells you.
A wet plug could also be a choke stuck on.

If the problem is not too serious you might get away with
some seafoam in the gas helping.
The carb could also be filled with yamaha carb cleaner or seafoam
and allowed to sit for a time and then drained to flush it out.

WS
-------  

Motorcycle Repair

All Answers


Answers by Expert:


Ask Experts

Volunteer


Wayne S.

Expertise

Licensed Motorcycle Mechanic, Knowledge of motorcycles from 1960 up, Japanese, British and most other brand motorcycle repairs.

Experience

Worked for Yamaha, Honda, Suzuki, Kawasaki British: Triumph, Norton, BSA Other: Most Scooters and Mo-Peds

Publications
Canadian Motorcycling magazine article

Education/Credentials
Licensed Motorcycle Mechanic

©2016 About.com. All rights reserved.