Bike won't start after rebuild.

[Silverkrown]

So a little back story. This bike ran when I took it apart. I have redone everything over the winter and just got done rewiring the bike. I had rebuild the carbs over the winter too.
After rewiring the bike I am getting spark at each plug and the head and taillight work as they should. The bike cranks but it seems it's not getting any gas because I'm not hearing the usually pop of trying to start just cranking of the starter. I have taken the carbs off about 5 times first re-checking the jets and making sure they are all clean. Adjusted float height to 26mm and then re did them to 32mm with no difference. Brass floats. Stock air box and exhaust. Fully charged battery. Just wondering if there is something obvious that I overlooked putting it back together. When I add gas to the clean carb and try to start it
I get a loud backfire out of the exhaust and then that is it. Thanks for any ideas. Here is a picture of the basic wiring diagram I used to wire the bike.

 

[bcware]

Do TCI bikes have a condenser? Did you paint the frame?

 

[Silverkrown]

Yes the frame has been painted. I'm guessing that it has a condensor but without looking I don't know for sure. I didn't change anything inside the motor although I guess I did rewire the bike. Maybe I missed something.

 

[bcware]

Some components, but not many (the condenser is one) need to ground to the frame. After a repaint grounding can be inhibited. I had to scratch the paint off mine to get good contact. The battery and harness have grounds too. Check 'em out before you go crazy.

 

[Silverkrown]

I'll have to double check the grounds but I have a bunch grounding right off the
battery that show on the wiring diagram. Would I still be getting spark if something wasn't grounded?

 

[16VGTIDave]

TCI doesn't have a condenser. Make sure that you have the ignition coils correctly connected. If the bike will crank using the electric starter and you have spark at the same time, chances are very good that you don't have a ground problem.

 

[walleye]

I had a similar problem, connected the coils according to my manual. Manual was wrong, connected the coils up the other way and the bike started.

 

[Silverkrown]

I had a similar problem, connected the coils according to my manual. Manual was wrong, connected the coils up the other way and the bike started.

Do you mean just connecting the plug wires to the other spark plugs or switching the actual wiring to the coils?

 

[16VGTIDave]

Switch the plug wires (to test) if your bike is a DOHC and it is difficult to get to the coils. If a SOHC, just switch the coil wires.

 

[Silverkrown]

I switch the coil wires and it didn't change anything. Still just cranks and don't get any pop. Pulled a spark plug to make sure it is still sparking and it is. It's like the gas isn't getting from the carb to the motor but I'm not sure why.

 

[bcware]

Check the compression. Check for fuel in the bowls What's your float height and what kind of floats do you have? Plastic or brass?

 

[Silverkrown]

There is gas in the float bowls. I have brass floats set at 32 but I had them at 26 and that didn't make any difference. When I crank the motor and put my hand over the carb I can feel it sucking in as it should. Took the carbs off and there is gas in the carb and some in the rubber carb boot. So I know gas is getting to at least there. I just put new plugs in too. It's like something is blocking from the carb to the spark plug. The spark plugs are dry and don't show sign of gas.

 

[bcware]

The float height should be 26 mm for brass floats. It'll make a big difference. If you're getting fuel at 32 mm it won't be much.

What air filters and exhaust do you have?

 

[Silverkrown]

As long as I have the carbs off I will adjust them back to the 26mm. I'm running stock airbox and stock exhaust.

 

[bcware]

Did you actually remove the jets and emulsion tube for cleaning? The pilot jet is probably going to matter most for starting and idle. There are very tiny holes in there that can get clogged in the passage way and the jet itself. The idle jet should also be covered by a plug. I have heard of people missing this plug.

The idle mixture screws should be around 2 to 3 turns out for stock intake and exhausts.

 

[Silverkrown]

Yes they were all removed and cleaned with carb cleaner and I made sure all of the
holes were clear. I also removed the slide and needle and made sure that was clean also.
I adjusted the floats back to 26 but that didn't make a difference unfortunately. This bike is driving me crazy. I've never had this much trouble getting one started. I got it started easier when I first got it and it hand't ran in years.

 

[bcware]

Go back to what YOU changed then. It's something you did. If it's electrical it is next to impossible for me to diagnose the problem.

Don't give up. The way to attack electrical problems is systematically. It takes a lot of patience because it might involve checking every single wire one at a time. If you gutted the electrical system to simplify the harness consider that it may have been put together incorrectly or you may have read a wiring diagram incorrectly.

You'd be surprised how fast you can find the problem if you just start checking wires. It's way more productive than randomly checking different systems on the bike. I've done that myself and wasted a few full days. Once I sat down with a multimeter and carefully checked every wire I found the problem within an hour.

It took me several attempts to wire up my aftermarket speedo with indicator lights built in; it looked simple but turned out to be more complex than I expected.

 

[xschris]

If you have done wiring work like you said you may have the wires to the coils backwards. The coils will spark but be 180* off ( right will fire when the left should).

 

[Silverkrown]

Yeah I'm guessing it's the electrical too since it did get fully rewired. I get spark with the plug out but is there a way to check if it is still getting spark under compression? I have already tried switching the coil wires but that didn't seem to make a difference. I'll have to go through the electrical again and try to figure it out.

 

[xschris]

Have you tried to spray some starting fluid in there?