i have a 1987 sportster 883 with the 1200 conversion on it and when trying to start it up it will pop out of the pipes a couple times (note can only make it backfire when i use starting fluid to try to fire it up but with regular gas no backfire) I have taken the carb apart and cleaned it i have checked the fuel delivery and it is spraying a 2 nice streams out of the carb jet. i have removed and replaced the plugs (wires are ok) i checked for spark and its firing. i then moved down to the timing plate and have tried to advance the timing all the way slowly until it was fully advanced and i have also retarded the timing all the way down slowly. i then tried to adjust the timing while starting it i started at the fully retarded position and slowly moved it until it was fully advanced still got nothing in any position. I am getting power every where im supposed to. I am out of ideas can anyone help? i dont know how to set the timing with out it running.. any ideas?

 

I'm confused, why are you using starting fluid to fire it up if it runs on gas? Is the backfiring the only problem? Do you have a timing light? Buy a manual if you do not own one, they are around $60 at the stealer.

 

yeah i have a book.. it only says how to time it if it is already running.. the bike has not run in 6 months i just finished putting the bike together it ran before the bike was taken apart the motor was not taken apart so technically it should fire right back up.. well i had a friend tell me that sometimes starting fluid will help to wake it up.. it will not start it will only backfire and pop.. honestly it sounds like the timing is way off but i he tried to move the plate while cranking it over and it does not fire in any position you put it in to far advansed and it will back fire out the carb to low retarded it will back fire out of the carb right in the middle it will back fire out the pipes...

 

It does sound like it is out of time. be careful about using either, you can get it hooked on that stuff. This sounds like a spark problem. How did you check the spark? pull the plug out, plug it in and rest it on the motor, kick it over and see what kind of spark you got. maybe the plug wires are crossed? remember you need 3 essentials to make a motor run.
1. gas
2.spark
3.air
if you got those 3, you got fire. next step is a compression test.

 

aside from learning the hard way i had a crack in my boot(i shocked the **** out of my self) i took the plug out and touched it to the jug and it sparked..

 

still cant get it fired up anyone else have any ideas??

 

Stop using the starter fluid. Check to see if both of the Sparkplugs are firing by removing them from the head and grounding them one-at-a-time to the head and checking them each for a spark jumping the gap between the two sparkplug electrodes when you try to start the bike up. If both of the sparkplugs are getting spark then move on to the timing. If your bike is timed correctly and the coil is producing an adequate spark that is getting through to the sparkplugs and you are getting the correct mixture of gas and air and there is enough compression then the bike will start. If you have moved the position of the timing plate from all the way advanced to all the way retarded and all the bike does is pop and backfire at every position that you have tried to start the bike at, in my opinion, and if it were my bike, I would start at making sure that the bike is timed correctly. Make sure that the front piston is in the Top Dead Center position and check for the timing mark through the timing hole by removing the timing hole inspection cover. If you can see that the timing mark is in the correct position through the timing hole and you know that you have the front piston is in the Top Dead Center position, then you can move forward with the next step in the timing sequence. If you are running points then you need to make sure that you have set the gap correctly when the points are in the open position and if you are running an electronic ignition, there should be an L.E.D. that will light up when the ignition plate is at the “points open” position. An electric ignition is normally supplied stock on your bike. So, now, it you know that both sparkplugs are getting spark and if you are certain that you have the front piston is the TDC position and you have correctly set the ignition plate in the correct position, try to start the bike up again and see what happens. Hopefully you will have a better result than before. Please post back with your results. Good luck with your Sportster and ride safe!

 

I know that you say that you put the bike back together again, but you didn't say what parts that you removed. If you removed any wires to the coil or to the ignition, please make sue that you put them back again correctly as well as making sure that the sparkplug wires are on the correct sparkplug. It is usually a little thing that causes a problem and not a big thing. Little things can be much cheaper and easier to fix than big things.

 

I find it hard to believe that if the thing ran perfectly fine when you parked it, that now the timing would be off.
I would find it really easy to believe that the fuel left in there(tank/petcock/carbs) hasn't been properly cleaned out. I've found that modern gas goes bad a lot and I mean A LOT faster than it used to(here in Calif at least), and some times we even need to use a sonic cleaner to properly clean some of the carb parts.
If I were you, I'd put the bike back (I mean the timing) the exact way you found it, and then drain and check out the tank, carbs, and petcock. After sitting for 6 months you need to inspect everything carefully, and have a professional do it if you're not sure how to.

 

ok ill try the timing again.. i believe it is electronic not points but i cant seem to find an led.. I got my volt meter out and checked all the power points and they are all registering what the book calls for.. i have put new gas in it and also cleaned out the carb. maybe the carb is not adjusted properly fuel is squirting out of the jet so i know its going through the bowl in to the carb and squirting past the butterfly flap.. i was not the one that took the bike apart. they guy i got it from took it apart and he is the one that said it ran. thats why i am where i am. if i take something apart i know how to put it back together.. you say that there is a timing mark window and so does the book but im unclear as to where this is.. I have taken the cover off where the timing plate is and i see a half moon thing with lines under it like a tape measure and a triangle cut out the i am un sure what that is but i see no window.. is this located in that same compartment or is it on the other side of the bike? i know it has to be something simple.. i took the tanks and seat off yesterday and went throuogh the wires and ther eis nothing shorted out. I re connected all of my grounds... ill look at the timing again today and i will stop using starting fluid. question if the coil is getting the correct power input can it lose power on the way to the plug? would plug wires be a wise replacement right now? i know the plugs are getting spark but maybe its just not hot enough of a spark?? thanks for the help so far! ill keep wrenching....