Bonneville America Forums Forums Technical Forums Performance Mods Pet cock

I have had a lot of backfires on startup.
They are coming from the carbs.
Could it be because of the stock petcock leaking?

Even if the stock petcock leaked, the floats and float needles should shut off the fuel flow. But if the temps are up, it is possible the gas in the bowls is making it into the throttle area or the air box. Try starting it without any choke and keep your hand off the throttle and see if that helps.

Will do.
Thanks for replying.

Mind that airbox don,t blow, i had the same and my airbox blew into about ten bits. not funny

I ran my reserve down too low last Friday night. Put in 4.3 gallons when I stopped for fuel, which was kind of stupid as I was riding across this small burb called HOUSTON. Probably passed a hundred gas stations, but knew which SHELL station I was heading to across town - being hardheaded. Had 173 miles on that tank. Anyway - no problems on that ride, but Sunday evening, about 35 miles on the tank, and my engine died on me maybe 6 times over the course of a 35 mile ride back across town. Restarted each time, but was kind of hairy there a few times as I was in the left (fast) lane on the freeways, in moderate traffic, and then BOOM - no power. After I got where I was going, made another 2-3 mile jog to a friends house - no problem. Then we went on a good 70 mile ride - no problem. I had 153 miles on this tank now, and had had no problems for 80 miles? I filled up again and rode home. Figure I had gotten so low in the tank on Friday night I must have picked up some crud from the bottom into the pickup tube, and it just never cut up until I started out Sunday. I'll never run that deep into reserve again. Still think a Pingle might be a good idea, too.

It backfired every time it died and restarted. I do need to look about the airbox to see that all is okay. Draining that tank and adding the new petcock may have to wait for cooler weather again, unless she gives me more trouble sooner.

I never roll the throttle when starting anymore. I had to break this habit since this bike. Other bikes I had required it.

Also.....

Get on the bike, turn the key on and do your ride checks. This will allow the carb heaters time to work (yeah, you don't need them in warm climates (bullcrap!!))

Pull your choke out full and then push it in a bit. Don't touch your throttle. Crank it up and she should start.

If not, I'd say there are other issues.....

Phil,
There is a temperature switch wired into the carb heater circuit. The heaters don't come on unless it's below 50 degrees F. (10 C)....
If it's warm outside, I'd try to start it with no choke and no throttle, then judiciously use the choke til the engine is running smooth/warmed up.

I replaced my Petcock after 400 miles. It leaked about a quart an hour. The plastic cone inside formed a groove that allowed gas to pass through. It flooded the carbs(the floats sunk..out of adjustment(you ALL might want to check your float adjustments)...and gas flowed into my K&N air filters and into the cylinders. I replaced mine with a Pingle I got from Brent. It is a way better product a delivers fuel efficiently. REPLACE YOUR PETCOCK!! It is the weak point of your Triumph. All those wierd problems like backfiring, running rich, and surging should go away. Also..replace your gas tank venting hose and carb venting hose with real rubber tubing line...and cap off ALL vacuum lines.