Left cylinder cutting out

Brett Kerby · Post by **Brett Kerby** » Sun Nov 08, 2009 10:05 pm

Driving my gt 250 the other day and all of a sudden the left cylinder starts cutting out, limp home on 1 cyl. Funny thing is it will idle just fine both cyl fire. It revs most of the time just fine, but put a load on it and twist the throttle and the left side cuts out?????? Hit it with seafoam pretty hard thinking it might have some dirt in the carb???/Nothing......Any help is greatly appreciated.........

Craig380 · Post by **Craig380** » Mon Nov 09, 2009 2:53 am

Before anything else, remember this piece of wisdom:

"75% of carb problems are caused by the ignition, and 75% of ignition problems are caused by the carbs"

But seriously, it's worth checking the battery is fully charged, the contact breaker points are clean & adjusted right, and maybe fit a new set of spark plugs and plug caps (or at least, swap them left to right). This will help eliminate most of the ignition possibilities.

Even if the charging system is weak or has died, a fully-charged battery will give you at least an couple of hours riding (without headlamp, etc).

Also check the battery terminal connections and the main earth, these should be tight & clean.

Good luck.

Coyote · Post by **Coyote** » Mon Nov 09, 2009 5:46 am

How old is your battery? I don't own a twin, but after browsing this forum for a few years now, it seems that 90% of left cylinder problems are caused by a weak or dying battery.

strainer · Post by **strainer** » Mon Nov 09, 2009 7:43 am

delete

Brett Kerby · Post by **Brett Kerby** » Mon Nov 09, 2009 9:28 pm

Thanks fellas, going out to charge the battery as we speak.

Coyote · Post by **Coyote** » Tue Nov 10, 2009 3:51 pm

Brett. Did the charge cure it?

Brett Kerby · Post by **Brett Kerby** » Wed Nov 11, 2009 9:32 pm

Not sure looks like it will be this week end before I can play with it some more... The charger said it was fully charged after like 30 seconds so I am not real hopeful.....Course the batt may have a dead cell or something, anyhow leaving it on main charge till Sat, and gonna install new plugs....Got my fingers crossed...

TLRam1 · Post by **TLRam1** » Thu Nov 12, 2009 2:01 am

What's the voltmeter say, what about if you turn the headlight on.

Cliff · Post by **Cliff** » Sat Nov 14, 2009 11:37 am

Why would a weak battery only affect the left cylinder? I'm asking because my GT550L fouled the left plug twice this year just before I put her away for the winter.

Brett Kerby · Post by **Brett Kerby** » Sat Nov 14, 2009 12:13 pm

Charged batt, put in new plugs and no change.....FUDGE! //turning on the light doesnt seem to make any diff at idle..... Gonna start tracing wires next I suppose...

rbond · Post by **rbond** » Tue Nov 17, 2009 11:15 am

With the battery fully charged, take it out for a quick run from cold. If it cuts out after it warms up good, it might be a condenser going bad. Swap it with a new one and try again same process. If it still does it the same way, it could be the coil. Swap coils and see if the problem now goes to the other cylinder, if still no joy, then it could be an air leak some where that opens up when it gets to full operating temp. Tracking this stuff down is sometimes painfully slow.....

Left cylinder cutting out

Left cylinder cutting out

Batt

cut out