Hi forum, long time follower of the forum, but this is my first post here. I'd thought you guys can help me out if possible.

I have a 99 Sportster 1200 Custom. In the last month, itis has really been having problems starting. The problem has progressively gotten worse to the point it wont start now. When it starts, it runs beautifully. A little rich but neverless it runs well. The factory carb just pooped out recently so I decided to replace it with a Mikuni carb. I also replaced the spark plugs, spark plug wires, ignition coil, and choke. I got it to run briefly and it ran perfectly, doesn't have the gas smell as when it had the factory carb.

Charged the battery overnight and in the morning tried started it. I gave it a rev on the gas and then hit the ignition. It would turn and turn but no ignition would happen. The minute I take my finger off the ignition, a really loud backfire would happen. Repeat this process for about 10 minutes and still no ignition. I would drain my battery, scare my dog with all the backfires (which are really loud and sound like gunshots), wake up any sleeping neighbors and **** off any that are awake.

I'm at the end of my rope and about ready to get rid of the sportster. I am the third owner and the second owner never said anything about starting problems. And the first couple of months (bought it in Dec) I had it, it had no problems starting, it was backed into and dropped about a month ago, it is then I started having the starting problems. I don't think the dropping of the bike had anything to do with it...what do you guys think?

Thanks guys..

 

Test your VOES switch.

 

check for spark, check for gas at plugs, go from there.

 

Recheck all the work you have done. may be something simple

 

+1

 

Have had two mechanics look at it and both are stumped. Have checked for spark....is getting spark....new carb...so it's getting fuel...when it runs, the engine runs beautifully...so no problems with fuel....

Had thought maybe the spark was not strong enough and not igniting the fuel...hence the new plugs, plug wires and iginition coil...What next????

And I thought the VOES switch was on 94 or older Harleys, mine's a 99, don't think it has a VOES switch.

 

YodaddyKieth just fixed a bike with similar symptoms... You may wanna PM him.

 

How does a VOES switch effect starting? And would replacing it or the Ignition Module help.

Thanks guys.

P.S. does anyone have directions on adjusting the Mikuni carb?

 

At zero vac, like when starting or at wide open throttle, it retards spark timing 4 degrees.....if it is faulty, you will have problems starting bike......depending on failure mode, it can cause perfectly runnin bike to backfire then die and not restart till bike is totally cooled off.....been there and done that and guys on this forum led me to the fix.

The switch is a simple on/off device triggered by manifold vac......one short hose from carb and one electrical plug are connected to it....you must usually remove tank to get ot it.....42 bucks later it's a done deal.....sorry, but I can't find old switch to post pic.

 

Ok, here is pic of the old VOES....VOES is short for vac operated electrical switch.

You are wrong in that is wasNOT included on older bikes, but it is a popular mod forthose oldercarbed bikes once upgraded to electronic ign......Carbed bikes with electronic ign need VOES for increased performance and drivability.