No fire on #3

[Guest]

After rebuilding the carbs following the tutorial on Basscliff's site, With new O-rings and gaskets, I have no fire on #3. I know I have spark, and compression, but a cold header pipe. Plug is dry, so I'm sure I'm not getting fuel.
I plan to tear it back down.
Is there a "standard" newbie mistake that I should look for in the carb? Anything in particular I should be looking for?

Thanks!!

[Brendan W]

I'd try swapping over the ht leads on that coil , probably #2. Plugs can spark in the open but not inside if the spark is weak. Next I'd open the float bowl drain with the fuel on prime and let it run into a clean jar for a bit, see if anything interesting shows up. A few gentle taps with a rubber mallet could help depending on how lucky you feel.
The bathtub rule ensures that most blockages happen just before and just after stripping.

[MatBirch]

Thanks! I have swapped leads and even coils, and checked the bowl. All is good. Probably should have included that info in the first place. Also, the valves are freshly adjusted.

[tkent02]

Not firing at idle, what if you take it out and open up the throttle?

Did you shoot spray carb cleaner through all of the tiny ports and passages in each carburetor to make sure they are all open? Each carb should spray in exactly the same pattern as all of the others from each opening if everything is clear.

[MatBirch]

Not firing at idle, what if you take it out and open up the throttle?

Did you shoot spray carb cleaner through all of the tiny ports and passages in each carburetor to make sure they are all open? Each carb should spray in exactly the same pattern as all of the others from each opening if everything is clear.

I'd of course like to think that I did a perfect job! Everything was spotless and seemed to be perfect when I put it back together, but I know myself... That all means nothing now. I haven't had a chance to run it yet, still on the table wrapping up the build. It did this same thing before I tore the bike down (I did all the recommended maintenance stuff to be sure I had a worthy candidate to build from. This was the only hiccup. I was hoping the valve adjustment would help.)

Thanks!

[Fjbj40]

Is the vacuum hose for the petcock capped? Is it hooked up? If not then you have a massive vacuum leak.

If you accelerate the engine does #3 get warm or hot then? If so I would guess a vacuum leak.

[MatBirch]

Got it! Tore down #3 and upon close inspection, the tip of the pilot jet was completly plugged with varnish. It was crystal clear, so it looked fine, even light shown through. I got it drilled out and cleaned up, and boom!

Thanks!

[tom203]

Life is good! Thanks for update- it's sure to help others

[Steve]

Got it! Tore down #3 and upon close inspection, the tip of the pilot jet was completly plugged with varnish. It was crystal clear, so it looked fine, even light shown through. I got it drilled out and cleaned up, and boom!

Thanks!

What size "drill" did you use?

I think you may now have other problems, because that jet is now much larger than it should be.

I prefer to use a single strand of copper wire to poke any crud out of jets. The copper is stronger than the crud, but won't hurt the brass.

.

[MatBirch]

What size "drill" did you use?

I think you may now have other problems, because that jet is now much larger than it should be.

I prefer to use a single strand of copper wire to poke any crud out of jets. The copper is stronger than the crud, but won't hurt the brass.

.

Sorry for the confusion, nope not a drill bit, just a strand of very tiny wire. Don't know where the spool of wire came from, but it's too thin and soft for ANYTHING else in life, but works great for carb jets

[spchips]

Right. Putting the jet in a drink and holding one or two strands of wore like drilling on a Lyne works well

[MatBirch]

Right. Putting the jet in a drink and holding one or two strands of wore like drilling on a Lyne works well

lost me! Lol