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I have a 2004 Vulcan 750. Oftentimes after the bike has sat for a few days, it just refuses to start. It cranks fine but doesn't even sound like it is firing at all. Everytime this happens, it will produce one gigantic backfire while cranking. I couldn't figure it out so I took it to a local shop. They tuned it (which I had already done, no help. Then they put carb kits in with no help.
Has anyone else had this sort of problem ? Suggestions appreciated ! Thanks, Mike
 

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Battery in good shape? sparkplug caps and wires good? Sparkplugs gapped properly? All battery terminals tight? Good negative ground?

Does your bike have FI or carbs? If FI, I'd check the fuel pump relay as the pressure might be intermittent. If carbs, check fuel flow and sediment build up in the float bowls.
 

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Sounds like you're flooding it when you try to start it. Don't choke it all the way, only pull the choke lever down about 2/3 of the way. Don't twist the throttle more than once better if you don't do it at all. Then just hit the starter for a few seconds....if it dosen't start right away let it sit several seconds then try again and mabye crack the throttle just a tiny bit.
 

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I don't know why it isn't starting, but the backfire is from being flooded after all the cranking. I had a 2003 VN750 that was hard to start, especially after sitting for a month or two but it did always start. I put Iridium plugs in it and that helped along with a yausa (sp?) battery. It still took a couple hits on the starter most times to get it to start though. Seems those bikes are just plain hard to start.

My VTX 1300 on the other hand is awesome. Set the choke, blip the throttle while hitting the starter and it fires immediately.
 

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The 750's are known to come from the factory set to run lean to meet emissions standards. You can take a look at the carbs to see if anyone has drilled out the caps over the air/fuel screws which will allow you to adjust the settings. If the caps are still in then you'll want to drill them and remove them with a drywall screw. You only need to drill (very gently) into the caps about 1/16th of an inch...just enough to break through the thin cap and then use a drywall screw to put into the tiny hole you just made to remove the cap.
Once removed check the screw settings first by turning them in until they seat (GENTLY) and then back them out to 2 or 2 1/2 turns and then try starting the engine and see how it runs.




Also, the 750 needs a fully charged battery to operate correctly. Many 750 owners swap out the battery for a Yuasa or Westco battery. Don't skimp and buy a cheap no name brand or you'll be buying another (good) one later.

Take some time and check out THIS WEBSITE for excellent information on the 750. Lots of great info and people there to help out.

Another good reference for troubleshooting the 750 is HERE.

If the bike has sat for some time you might have a fuel/carb problem. Buy a can of Sea Foam and add one ounce per gallon of gas and after getting the motor running ride the bike to help clean out the fuel system. You can buy it at Napa Auto Parts or Wal Mart or other automotive stores. A stronger Sea Foam mixture won't hurt the engine so if you suspect bad gas then bump up the ratio to 2 ounces per gallon of gas.

Once you get the bike running great you'll love every mile of it. Good luck!
 
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