750 twin won't start when cold

OK I'm down to my last (latest) problem with the bike.
I've done the wired George rewire and cleaned, synched got the carbs squared away. New vacuum hoses etc.
It just does not want to start when it is cold. After trying today I pulled the plugs and they were bone dry with fuel smell on them at all. I took 2 plastic bags and shoved into the intake throats on the carbs. I spun the motor over 4 or 5 times and pulled them out. Then I touched the starter and it fired up like a brand new one.
I understand the carbs are not equipped with a choke rather an enrichner so how do I adjust the carbs to get enough fuel to get it to fire when its been sitting for a while?
When it has been warmed up it fires right up.
So what do I need to do?

Wildh2oskier wrote:

OK I'm down to my last (latest) problem with the bike.
I've done the wired George rewire and cleaned, synched got the carbs squared away. New vacuum hoses etc.
It just does not want to start when it is cold. After trying today I pulled the plugs and they were bone dry with fuel smell on them at all. I took 2 plastic bags and shoved into the intake throats on the carbs. I spun the motor over 4 or 5 times and pulled them out. Then I touched the starter and it fired up like a brand new one.
I understand the carbs are not equipped with a choke rather an enrichner so how do I adjust the carbs to get enough fuel to get it to fire when its been sitting for a while?
When it has been warmed up it fires right up.
So what do I need to do?

If not already done, try the initial cold start-up with choke fully on, and without touching the throttle at all.

The enrichner circuits are designed to operate with no throttle whatsoever.

Let us know if that fails to resolve the cold starting issue, so we may then consider the enrichener circuit itself.

Meanwhile, are these the stock oem carbs?

Good Luck!

Wildh2oskier wrote:

OK I'm down to my last (latest) problem with the bike.
I've done the wired George rewire and cleaned, synched got the carbs squared away. New vacuum hoses etc.
It just does not want to start when it is cold. After trying today I pulled the plugs and they were bone dry with fuel smell on them at all. I took 2 plastic bags and shoved into the intake throats on the carbs. I spun the motor over 4 or 5 times and pulled them out. Then I touched the starter and it fired up like a brand new one.
I understand the carbs are not equipped with a choke rather an enrichner so how do I adjust the carbs to get enough fuel to get it to fire when its been sitting for a while?
When it has been warmed up it fires right up.
So what do I need to do?

Fix the "choke" (richening circuit) so it works as designed. I have a 750 twin and it starts dead cold on one spin. If that choke isn't working, you are going to burn your starter out cranking it.

I can't tell what carbs or pipes you have from the picture, but I did go from the ridiculously lean 40 pilot jet to a 50 on mine. That does make it run better cold and allow you to turn the choke off sooner, but it won't start a cold engine without the choke's help.

Its the stock carbs, air filter and the pipes are off of a 2000 HD Dyna. Here is a link to a better version of that pic.
kzrider.com/index.php?option=com_ponygal...&func=detail&id=2726

Using the enrichener the way you say has no effect what so ever. So I'm willing to bet that is where we need to start.

I agree with starting at the enrichment circuit in the carbs.






Really, I just had to post something on topic so I could tell you how good the wheels looked

Bead blasted and clear coated?


I'll go sit in the corner now

Wildh2oskier wrote:

Its the stock carbs, air filter and the pipes are off of a 2000 HD Dyna.

Most harley pipes are about one click away from a straight pipe. It could be making your engine run lean, but it should still start without all the cranking if the choke works.

Does anyone have a diagram and/or a tutorial on this enrichener circuit?

Wildh2oskier wrote:

Does anyone have a diagram and/or a tutorial on this enrichener circuit?

It's in the FSM, I don't have any way to post it. It's a starter jet, starter pipe, starter plunger, starter air passage, plunger chamber, and mixture passage.

The plunger is lifted by the lever on the LHS of each carb. Raising it pulls the needle out of the jet seat and allows fuel to go past it.

From the FSM: "Clogged starter pipe air bleed holes will cause insufficient atomization, thus impairing the starter system."