getting a puff of air back through my #3 carb....

....ocationally.Why does this happen?

BoZ650 wrote:

getting a puff of air back through my #3 carb...Why does this happen?

Possibly an issue with #3 intake valve seating. If not already done, could perform compression test and check valve clearance. If gap's okay but compression low, then maybe a leakdown test to confirm #3 intake valve is seating okay.

Good Luck!

The slight chuff could be called a backfire. The mixture isn't fully being ignited. Could be a variety of reasons... valve hanging, poor spark, ignition timing, air leak... any number of things. You didn't mention whether the bike has been tuned up in the last 30 years. That would be a good place to start and look for air leaks in the intake or exhaust system... carb holders, re-use of used exhaust gaskets, etc will often do this.

would these symtoms happen if the carbs were starving for fuel?Was riding today and it bogged down and died.Would turn over but not start.So I looked in the clear fuel filter and noticed no fuel.I moved the fuel line back and forth and fuel started to flow into the filter again.Bike started right up and ran good.I have what looks to be rust sitting in the filter so I Suspect thats the culprit.Could this be the root of all my carb problems,hard cold starts,and the slight backfire in the carb???

Definitely. Sounds like you should pick up a new tank or clean your tank. Pull off the petcock and look to see what is on the screen. If you see rust debris, you need to deal with the rust (or get another tank). If the rust is minimal, you can fill the tank with a solution of phosphoric acid and water and let it sit overnight then flush the tank and refill with gas immediately after drying with compressed air. If the rust is pretty heavy or the pieces of rust you find are on the large side, buy a POR 15 kit which includes a prep cleaner (acid) and a liner. Be prepared to repaint the tank.

I filled up at a small station a couple of weeks ago,, the bike started acting like it was starving, had to run on reserve to get home, long story shot,,, the filter on the petcock was covered with a fine sandy looking material, rebuilt petcock and cleand the tank new filters was required

Thanks George and BSK,Im looking for a good tank now but in the mean time I filled the tank up for the 1st time and she runs excellent on a full tank of gas, so for now Ill keep it full and hope for the best.I also have a spare in line filter with me just in case.Oh Yeh all previous symtoms seem to have gone away,Even the cold starting issue.Thanks for your help!!
Tony

BoZ650 wrote:

... runs excellent on a full tank of gas, so for now Ill keep it full and hope for the best....

If problem recurs with less than full tank, it might be fuel starvation caused by a clogged vent in the fuel tank cap.

Could try releasing the cap and running with the cap unsnapped to determine whether there's any improvement in fuel flow from the tank or if that makes any difference.

Good Luck!

I never thought of that Patton but it makes sense.Ill give it a shot if the situation presents itself again,But I hope it doesent!Thanks.
Tony