Sporty backfiring and poor idle

I have a 1997 1200 Sporty. It recently started excessive backfiring when driven and poor idle. It is idling around 500-600prm and then dying. I have cleaned and re-gapped the plugs and cleaned my air filter. The problem started after I removed my seat and tank to run an electrical wire for my GPS, but I didn't mess with anything else. Not sure if I accidentally knocked something out of adjustment or if this is just a coincidence. Any help is appreciated!

Sounds like an intake leak, Did you by change bump the carb or intake when you removed the tank, you can spray ether or wd 40 around the intake or run a hose from your propane torch around the seals by the head, if the idle changes,(motor speeds up) you found your leak, I bet since it happened right after you removed your tank, you more than likely disturbed the seal and it is sucking air. Hope this helps Todd

good call and advice from duke76

I agree with " may be leaking air intake " other areas to ck for air leak is the carb to intake manifold-----coil wires to plugs shorting or crossfire.....pinching wire when putting tank on as the feed into the hollow of tank, is also very possible....... LET US KNOW what you find or don't find please.... thanks

signed....REDHEAD

choffff and sputter another reason

:fight: NOW I was thinking :angry: MAY BE you loosened a bit of MUCK that went into carb and gas is in short supply by the float needle valve??????

This happened to me once when I had my tank OFF ----- an EARWIG crawled into the gas tube when I wasn't looking and DIED (got high off fumes).. Sure made a MESS of the inlet @ the float needle valve (very small opening)....... It sure was too lean to run much at all.....

JUST ANOTHER THOUGHT! signed....REDHEAD

You could also check the petcock, when you took off the tank it could have spread crap around choking off the petcock restricting fuel flow to the carb making it act the same as an earwig in the inlet
Good Luck, let us know what you find

Found the problem

Thanks to all for your help!
As it turns out, it was a vacume leak. When I re-installed the tank, I completely forgot to re-connect the vacume hose that connects to the back of the petcock. Since it was hidden back there, I never would have seen it if it were not for the good advice form you guys.

THANKS!!!!!!!!!!!!!!!!!!!!!!!!

Ooooooosssppppyyyy

That is the thing MOST PEOPLE OVERLOOK My friend spent HOURS disassembly-and together-dis and together- and ended up trailering bike to the STEALERS..... they spent 2 hours of shop time and charged him for the FULL amount by saying other things were FOUND to be wrong..............

GOOD FIND!!!!

signed....REDHEAD :angry:

Glad you found it, :devil:

Regarding petcock problem 2

Chucktx,
Thanks. I didn't know the petcock worked off the vacume. I'm glad you mentioned that because here is what happened. When I first re-installed the tank after running my GPS wiring, I couldn't start the bike. (This is way before I found the vacume hose disconnected) I disconnected the fuel line from the petcock to see if gas was flowing and it was not. I thought that somehow the petcock internals were stuck in the off position even though I had the lever turned on. I removed the tank and disassembled the back of the petcock were there is a gasket. I checked the gasket position, which seemed OK, and re assembled the petcock and re-installed the tank. Then I had gas flowing but of course the vacume hose was still off at this time, causing the poor running condition. Have I damaged the petcock? Now that the vacume hose is on the petcock, if I disconnect the fuel line and turn the petcock on, I should not have gas flowing, is that correct? What else can I do to tell if I have the problem you are discribing? Is there a petcock re-build kit I can get from HD?

Thanks!!
Mike

The idea of the vacuum operated petcock is fuel won't flow unless the engine is running. personally I don't like them, I prefer gravity type, that way when you turn it on gas flows turn it off, it stops. Easier to drain your tank with the gravity type, less to go wrong with them. Gravity has been around for a long time and it works...just drop something to test for it
There may be a rebuild kit for the vacuum type and you may have damaged the diaphram but what I'd do is get a nice shiny regular gravity type petcock, install it, plug off the vacuum line at the carb and get in the habit of turning off the fuel when you get off the bike. JMHO :devil:

Questions on the pingle petcock solution

OK it sounds like a gravity fed petcock is a good solution. A couple of simple questions:

1 When I go to the dealer, do I just ask for a "pingle" petcock? Is this something I should get from HD or is there a better source?

2 The vacume hose. I should follow it back to the manifold and cap it off. What should I use to cap it with? I just want to make sure I'm doing this right.

Thanks again guys!

Just a rubber cap over the fitting on the manifold, paint shop ,rad shop or hardware store should have em, or if you're going to buy from a dealer or an Indy, tell em you want to plug off the vacuum line and they should be able to fix you up.
Yeah just tell em you want a Pingel petcock, Indy or dealer they 'll know what you want, or should anyway..... Here's a link to one on FleaBay goin cheap, but you pays yer money and takes your chances.

HIGH FLOW "PINGEL" STYLE PETCOCK FOR HARLEY OR CUSTOM - (eBay.ca item 220291181062 end time 13-Oct-08 20:29:08 EDT)

OHHHHHHH!!!! I just HATE IT whan I do something like that!!!

You are SO in good hands here....mine just spits every now and then just to be obstinate in her own way..but such is a woman's perogative.