Motorcycle Forum banner

2006 Honda Shadow VT750DC dies on idle with choke, and low end throttle

2563 Views 7 Replies 5 Participants Last post by  SemiFast
Hey all!

First bike, first post.

Got a 2006 Honda Shadow VT750DC (dual carb), 5700 miles. I cant get the bike to run.

Symptoms: It will start on full choke but then die out after 30 seconds or so, if I set it to 陆 choke after 30 seconds it will run an additional 10-15 seconds then die. It will not start or idle without the choke.

Throttle causes a lag and sputter during the first quarter throttle. Once its opened all the way up it will run at max RPM but when I throttle back to close to quarter throttle it will die.

Based on what Iv researched to far most folks point to an issue with the pilot jets, that its not getting enough fuel during idle as well as lower throttle levels.

Here鈥檚 what Iv done so far:

  • Both carbs have been disassembled, soaked and scrubbed with carb cleaner. Iv soaked and run fine wire thru all 4 jets. You can clearly see thru all 4 jets; pilot and main, on both carbs.
  • Floats work as expected, no discolorations or deformations.
  • Ran compressed air thru the main airways of the main carb body, nothing is blocking the pilot or main jet airways that I can tell.
  • Carb boots are in good shape, still soft and malleable, forms a good seal when clams are screwed down.
  • Iv checked for air leaks throughout the main engine area, Iv sprayed starter fluid on all the boots and gaskets. No RPM increase anywhere.
  • Fuel/Air mixture screw has been cleaned, reset, and re-zeroed, currently at 3 turns out.
  • Air intake and exhaust are both factory and in good shape, newer air filter.
  • Battery is newer and seems to be working fine based on a meter test.
  • Fuel pump seems to be working fine initially, pump fills the fuel system and carb with fuel right away after reinstalling the carb on the motorcycle and the bike turns over and starts with choke at 100%.
  • No blocked or constricted airflow anywhere that I can tell
  • All tubing around the motor and carbs are in good shape, no cracking or splitting middle of the tube or at the ends.
  • Spark test has been done, all 4 produce a good spark.
  • Plugs are in good shape; they were replaced fairly recently.
  • Black soot on the outer ring and white soot on the inner ceramic rod/pin, seems to have a decent fuel mix but Im no expert (pics included for reference).
My best guess is that after all this I have to start examining the electrical system. Part of me says its probably something dumb that I am overlooking as a naab but you don鈥檛 know what you don鈥檛 know.

Any suggestions would be appreciated.

Thanks yall!
See less See more
1 - 8 of 8 Posts
Hey all!

First bike, first post.

Got a 2006 Honda Shadow VT750DC (dual carb), 5700 miles. I cant get the bike to run.

Symptoms: It will start on full choke but then die out after 30 seconds or so, if I set it to 陆 choke after 30 seconds it will run an additional 10-15 seconds then die. It will not start or idle without the choke.

Throttle causes a lag and sputter during the first quarter throttle. Once its opened all the way up it will run at max RPM but when I throttle back to close to quarter throttle it will die.

Based on what Iv researched to far most folks point to an issue with the pilot jets, that its not getting enough fuel during idle as well as lower throttle levels.

Here鈥檚 what Iv done so far:

  • Both carbs have been disassembled, soaked and scrubbed with carb cleaner. Iv soaked and run fine wire thru all 4 jets. You can clearly see thru all 4 jets; pilot and main, on both carbs.
  • Floats work as expected, no discolorations or deformations.
  • Ran compressed air thru the main airways of the main carb body, nothing is blocking the pilot or main jet airways that I can tell.
  • Carb boots are in good shape, still soft and malleable, forms a good seal when clams are screwed down.
  • Iv checked for air leaks throughout the main engine area, Iv sprayed starter fluid on all the boots and gaskets. No RPM increase anywhere.
  • Fuel/Air mixture screw has been cleaned, reset, and re-zeroed, currently at 3 turns out.
  • Air intake and exhaust are both factory and in good shape, newer air filter.
  • Battery is newer and seems to be working fine based on a meter test.
  • Fuel pump seems to be working fine initially, pump fills the fuel system and carb with fuel right away after reinstalling the carb on the motorcycle and the bike turns over and starts with choke at 100%.
  • No blocked or constricted airflow anywhere that I can tell
  • All tubing around the motor and carbs are in good shape, no cracking or splitting middle of the tube or at the ends.
  • Spark test has been done, all 4 produce a good spark.
  • Plugs are in good shape; they were replaced fairly recently.
  • Black soot on the outer ring and white soot on the inner ceramic rod/pin, seems to have a decent fuel mix but Im no expert (pics included for reference).
My best guess is that after all this I have to start examining the electrical system. Part of me says its probably something dumb that I am overlooking as a naab but you don鈥檛 know what you don鈥檛 know.

Any suggestions would be appreciated.

Thanks yall!
Looks like you've attached this problem logically. I would adjust the fuel/air mixture screw in to 2 to 2.5 turns. Your more than likely on the right track with electrical.
"Both carbs have been disassembled, soaked and scrubbed with carb cleaner. Iv soaked and run fine wire thru all 4 jets. You can clearly see thru all 4 jets; pilot and main, on both carbs." ... did you disassemble it enough to clean the holes in the sides of the emulsion tubes?

I would replace the fuel pump and if it makes no improvement then at the very least you have a spare. They really are not very good fuel pumps and the original is not going to out live the rest of the bike.

Carburetors can't work good if the intake pressures are not good, the intake pressure will not be good if the valve clearances are too tight. Compression test and adjust your valve clearances, if they have never been done it is time.
Carburetors can't work good if the intake pressures are not good, the intake pressure will not be good if the valve clearances are too tight. Compression test and adjust your valve clearances, if they have never been done it is time.
Does this apply throughout the rev range. He mentions its fine at max rev.
Does this apply throughout the rev range. He mentions its fine at max rev.
The first symptom of tight valve clearances is hard starting, particularly after it stalls out and it is already warm. At least that has always been how it happens for me. It's harder to asses engine performance at wot unless you have access to a dyno and I've never had that luxury. I'm usually fixing the stuff out in the woods making it work with anything I can find.
The first symptom of tight valve clearances is hard starting, particularly after it stalls out and it is already warm. At least that has always been how it happens for me. It's harder to asses engine performance at wot unless you have access to a dyno and I've never had that luxury. I'm usually fixing the stuff out in the woods making it work with anything I can find.
gotcha.
If it runs at full choke, even for a minute but dies out when you de choke it why would you think it is electrical? Basd on this symptom I would like at fuel delivery. Start at the tank and make sure fuel is leaving the tank properly. If it is coming out of the petcock fine pull the line loose from the carb(s) and make sure it is getting there. If it is getting there make sure there is good spray into the carb(s) throat. If all that checks out, after running it check the plugs and see what they look like.
The ports (passages) inside the carburetor body itself are probably still blocked.
Throttle causes a lag and sputter during the first quarter throttle. Once its opened all the way up it will run at max RPM but when I throttle back to close to quarter throttle it will die.
Yep, clogged slow speed ports inside the carburetors body. Pretty Much Every Time...

S F
1 - 8 of 8 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top