[Will750]

Can't rule out the cdi yet. Not sure what tests there are for it, check the manual.

You have decent spark, but is it at the correct time.

Something about the start button, it means something, but on this system I'm not sure what. That symptom has been mentioned here before, but I'm not sure if anyone ever posted their fix. Never hurts to try the forum search.

Sometimes on old points ign systems, running only in the start position, meant a defective ballast resistor. But the ballast resistor on those old systems was there to keep the points from getting more than 9v, to reduce burning of the contacts. Could be something similar happening in the CDI, because there is that white/red wire between the start button and the CDI. The ignition timing could be going numb when you release the start button.

i will definatly check out the start button. Im sure i seen a few posts on that somewhere here. I tried it again today. Fully charged the battery, cleand the plugs, and drained the carbs. Got some backfire again. Then after several tries she finaly fired up. However it would not fire with the choke on. I had to keep twisting the trottle to keep her alive. As soon as i stopped reving it cut out. I played around with the mixture screw which led to it firing in the first place then when i played with mixture screw again it would not fire. Im thinking now more on a fuel issue than mechanical. It started and thats a huge step in the right direction.

 

[Spockster]

i will definatly check out the start button. Im sure i seen a few posts on that somewhere here. I tried it again today. Fully charged the battery, cleand the plugs, and drained the carbs. Got some backfire again. Then after several tries she finaly fired up. However it would not fire with the choke on. I had to keep twisting the trottle to keep her alive. As soon as i stopped reving it cut out. I played around with the mixture screw which led to it firing in the first place then when i played with mixture screw again it would not fire. Im thinking now more on a fuel issue than mechanical. It started and thats a huge step in the right direction.

Did you notice any smoke at all, or a gassy smell once it fired up?

 

[Will750]

i will definatly check out the start button. Im sure i seen a few posts on that somewhere here. I tried it again today. Fully charged the battery, cleand the plugs, and drained the carbs. Got some backfire again. Then after several tries she finaly fired up. However it would not fire with the choke on. I had to keep twisting the trottle to keep her alive. As soon as i stopped reving it cut out. I played around with the mixture screw which led to it firing in the first place then when i played with mixture screw again it would not fire. Im thinking now more on a fuel issue than mechanical. It started and thats a huge step in the right direction.

Did you notice any smoke at all, or a gassy smell once it fired up?

yes and yes. It smoked like crazy at first. But then it calmed down. Does this mean trouble?

 

[Spockster]

yes and yes. It smoked like crazy at first. But then it calmed down. Does this mean trouble?

I suspect it could be flooding, too rich on gas, but I'm not there to see and hear.

When one is flooding, it might start only with a lot of throttle, will run ragged at first then smooth out if it's able to clear the excess gas. Meanwhile, you should see some black smoke. The exception of this engine is that it can flood bad enough to make white gas vapor, which is rare on gasoline engines.

Flooding would make it impossible to run with the choke on. If it continues flooding, it will die when you let off the throttle, because there's less air for the extra fuel.

 

[Will750]

yes and yes. It smoked like crazy at first. But then it calmed down. Does this mean trouble?

I suspect it could be flooding, too rich on gas, but I'm not there to see and hear.

When one is flooding, it might start only with a lot of throttle, will run ragged at first then smooth out if it's able to clear the excess gas. Meanwhile, you should see some black smoke. The exception of this engine is that it can flood bad enough to make white gas vapor, which is rare on gasoline engines.

Flooding would make it impossible to run with the choke on. If it continues flooding, it will die when you let off the throttle, because there's less air for the extra fuel.

ok makes sense. I have ordered a carb rebuilt kit. So it should clear up the flooding issue. These carbs are old and even tho there clean i still might have missed some gunk. Should i stay with standared jets seen as i have done the ear shave. Also still has stock exhausts

 

[Spockster]

ok makes sense. I have ordered a carb rebuilt kit. So it should clear up the flooding issue. These carbs are old and even tho there clean i still might have missed some gunk. Should i stay with standared jets seen as i have done the ear shave. Also still has stock exhausts

Stick with the stock jets until you get it running and can read the plugs.

Mine runs fine on the stock jets, shaved with stock exhaust.

 

[Will750]

ok makes sense. I have ordered a carb rebuilt kit. So it should clear up the flooding issue. These carbs are old and even tho there clean i still might have missed some gunk. Should i stay with standared jets seen as i have done the ear shave. Also still has stock exhausts

Stick with the stock jets until you get it running and can read the plugs.

Mine runs fine on the stock jets, shaved with stock exhaust.

ok thank you. Spockster your help and advice has been outstanding. I want to thank you for all your help this far. You have replyed to every query i have had and that means a lot. So thank yo so much.

 

[Spockster]

ok thank you. Spockster your help and advice has been outstanding. I want to thank you for all your help this far. You have replyed to every query i have had and that means a lot. So thank yo so much.

You're welcome, and your reply is appreciated. Keep at it, you'll get it going.

 

[Spockster]

I've found that soaking in white vinegar does wonders for jets.

I left a couple of wrenches soaking two weeks, forgot about them. The rust was gone, but so was the chrome.

 

[Will750]

I've found that soaking in white vinegar does wonders for jets.

I left a couple of wrenches soaking two weeks, forgot about them. The rust was gone, but so was the chrome. /forum/images/smilies/icon_biggrin.gif

lol sounds about right. Done the same thing myself 😂. Right the only thing i can think of that i didnt clean was the jet on the bottom right in the picture. I was unable to get it out. Which jet is this and is it suppose to come out?

 

[Spockster]

lol sounds about right. Done the same thing myself 😂. Right the only thing i can think of that i didnt clean was the jet on the bottom right in the picture. I was unable to get it out. Which jet is this and is it suppose to come out?

Pretty sure that's an air bleed and it's pressed in. Don't try to remove it, but shoot some spray carb cleaner, and compressed air if you have it, to make sure it's open. The carb cleaner should come out somewhere else.

Be sure to clean the tiny emulsion holes on the side of the main jet.

 

[Will750]

lol sounds about right. Done the same thing myself 😂. Right the only thing i can think of that i didnt clean was the jet on the bottom right in the picture. I was unable to get it out. Which jet is this and is it suppose to come out?

Pretty sure that's an air bleed and it's pressed in. Don't try to remove it, but shoot some spray carb cleaner, and compressed air if you have it, to make sure it's open. The carb cleaner should come out somewhere else.

Be sure to clean the tiny emulsion holes on the side of the main jet.

ok no prob. Looks like it might be blocked and id say the past owner tried to take it out as there is scratch marks on it. Im waiting on a rebuild kit to arrive so i might just pull it apart again and soak the whole thing in carb cleaner for a few hours. Hopefully that will loosen any hidden deposits that i can not get to. Thanks for the reply

 

[Chris Allunario]

Have you managed to get it started yet? Did you move the stator when you had the motor open? I ran into a similar issue when I reinstalled the stator with the wrong orientation which meant the ignition timing was completely off

 

[One1]

These bikes will test you. Lol. If i knew then what i know now after building VN750’s for 10 years I probably wouldn’t have bought it. Lol. The good news is that you’ll eventually learn what each things makes it act like and you’ll Be able to fix it by ear. at this point i usually don’t have to touch it to know what’s wrong, but even now I still get surprised by the bike with quirky things it does.