2004 v star 650 back cylinder does not fire

Cylinder not firing. Remove plug and verify spark. Also verify fuel to cylinder.

It very likely coming from the banjo bolt that retains the lube line that feeds the top of the engine. Remove the spark plug cover and check the tightness of the large bolt you will see. I have seen this problem a few times.

More likely a spark plug, spark plug wire or coil.

Generally the leads are a tight stretch and having slack if around the wrong way. Take the sparkplugs out and connect each to your best choice of leads. Place these so they are resting metal to metal on the cylinder heads. Place your finger tip tightly over front cylinder sparkplug hole and rotate engine with ignition on. When compression is felt (your finger will "pop" off hole) and the sparkplug that sparks will be the front cylinder coil and lead. Repeat procedure with rear cylinder to confirm.....mark F and R on lead caps when your done!
Cheers.

Hi there,
You will need to do some diagnosing of the problem. Some things to check

• compression check across all cylinders. Low compression(less than 100 lbs in a cylinder will prevent it from firing. They should all be with 20 pounds of each other.
• carby to that cylinder may have a clogged air passage or jet.
• try a new plug in that cylinder.
• check for air leaks about the problem cylinder air intake. Use aerosol carb cleaner to spray about the manifold gaskets and carb mount. The revs will change if there is an air leak.

MOst probably you will need to strip and clean down the carbs if you have good compression and spark. Fuel is the only thing left :) Sometimes running some fuel system cleaner additive will also resolve the issue for you without tearing down the carbies. Goodluck regards robotek

if this is a four cylinder engine it will be the one further from the fan belt,check the spark plug but it also can be the ignition coil for that cylinder.

first check the sprkplug to see if it is making sparks,if not replace the sparkplug and try again,if still no joy check that the sparkplug cap is tight on the lead,if still nothing the rear coil may have gone faulty,hope this helps