1978 kz650 D1 keeps bogging down.

Hey all. Just joined the group and am loving the bikes. I have a 78 kz650 D1 that bogged down yesterday as I was going upward in elevation. Got the bike back down closer to sea level, and it is still bogging down. I looked at the fuel bubbler and it has an air bubble in it. Is that normal to have air in the bubbler? And can anyone help me with the bogging down problem. thanks for any help guys. Ride safe.

Sounds like some trash in the carbs. Did you hit reserve recently? Has it always done this or just started recently?

I have not hit the reserve recently, cause I keep it filled up. And it just started this yesterday.

Could be a number of things. I would check your fuel cap to make sure the vent is not clogged. Try running the bike with the cap open and see if it helps if so you have a clog in the vent if not we will go to step 2.

Welcome to KZr sneekydevil.

By "fuel bubbler", I'm assuming you mean fuel filter?

If so, and depending on it's size, it wouldn't be uncommon for it to have a small air bubble in it. If it is to large (or very fine mesh) filter, it can possibly cause your stated problem, since your bike might be consuming fuel faster than it can actually filter it. It even might be as simple as it being clogged.

FWIW, most problems can often be traced back to what maintenance or changes have recently been performed (oil / filter change, cleaned air filter, etc.) on a bike.

Thanks to everyone who had advice. Got the bike fixed. Seems that some paint chipped off in the gas tank. Just a spec, but enough to keep the bike bogging down. Drained the carbs and she runs like a champ. Thanks again.