Cold start is a pain!

[cmyoch]

Can any of you carb gurus help me out with this? My 78 runs outstanding once warmed up but a cold start is a real bitch. I've noticed on other bikes that when you set the choke, the rpm's increase and hold until you take the choke off. Mine will fire a bit then die. I have to start it with the choke on and off to finally get it to go. By the way, it's kick only so I'm breaking a sweat by the time I'm running. Again, after she's warm, she runs great. I have manual petcocks with a vacuum line connected to both boots and the carbs were rebuilt last fall.

Any advice?

 

[littlebill31]

When was the last time they were totally cleaned? I mean stripping every part off, every jet out, and cleaned.

 

[retiredgentleman]

Cold starting needs a very rich mixture.................about 3:1. You either restrict the air flow or you increase the fuel flow. These carbs rely on increased fuel.

The increased fuel comes from a small passageway (jet) in the bottom of the float bowl. Make sure its clear.

You also need a charged battery, timing set correctly, and good compression.

 

[cmyoch]

They were thouroughly cleaned last fall, say October. I periodically run some sea foam through the tank to keep it clean. I had a compression check a couple months back and the readings were 150 psi on both sides. My charging system is functioning properly and as far as I know, the timing is set. I'll drop the bowls and see if there is any blockage. I assume I can take a wire and open it up without doing any damage?

 

[gggGary]

Our "chokes" don't have a fast idle cam for the throttle, so yes they are touchy till you get past the warm up period. On the 34's float fuel level affects cold starting also. the lower the level the harder cold starts are. I suspect this is true on 38s also but have not verified it.

 

[cmyoch]

That's good to know. I thought something was seriusly wrong with the choke. I get 2 seconds on choke then it dies. I don't know where my floats are set since I paid a guy to rebuild them for me. I assume adjusting them isn't a huge ordeal? That is if this is the issue here.

 

[weekendrider]

cmyoch,
Note in RG's pic. that is a NON-removable jet. Someone "poking" it out with a wire may be the problem. I clean those with cleaner and compressed air ONLY.
And I do have assortment of "pokers" to choose from but like said once it is too big it's too late.

 

[bloodthirstysystem]

time for a carb cleaning.. i do it after every winter, and sometimes in the middle of the summer..

this is how i start mine, try it. with the power off, give 2 or 3 kicks with the choke on. then turn on power and kick. should start first one

 

[cmyoch]

I rode it to work today. I'll give that a try. I guess I haven't had the bike long enough to develop a habit on how to start it. Thanks!

 

[TeeCat]

time for a carb cleaning.. i do it after every winter, and sometimes in the middle of the summer..

this is how i start mine, try it. with the power off, give 2 or 3 kicks with the choke on. then turn on power and kick. should start first one

+1 on this. "Prime" the cylinders with a "cold" kick or two (choke/enrichener engaged), and then it should light off when you go "hot".

Also, when you start to come off the choke (to avoid fouling plugs), you may have to use some throttle until the carbs will respond properly/idle unassisted. They are indeed fussy that way.

TC

 

[cmyoch]

It's good to know that other bikes are fussy when they wake up. I thought I was having a serious issue at first I got to the end of the street and she was idling fine.

 

[TeeCat]

ooooooooh, yeah. Fussy. And cold blooded as all get out. Even with my single Mikuni VM, properly (now, I think) jetted, there's this little ritual that she seems to want. Not quite to the point of having to light votive candles and say a novena... but you get the idea.

TC

 

[cmyoch]

Why do you think I refer to my bike as "she" or "her"? I feel like I need to caress her tank and give her a kiss on the headlight and whisper sweet nothings just to get her to agree with me. The way she is now, I jump on her, force her awake, and hang on for the first block until she cooperates.

 

[BigBoreSwede]

Hi.

I´ve notice that with the igniton a LITTLE bit of the bike is kind of hard to fire up but it runs much better once warmed up.

If you kickstart it you´ll also notice it´s harder to kick with the igniton set slightly off.

Maybe it´s worth setting the ignition of not already done.

/BigBoreSwede

 

[uknowme2goog]

what is sea foam?

 

[cmyoch]

It's a multi use additive that I've only used in fuel. I've had way more success with Sea Foam versus any other additive. I put it in all my tanks when storing equipment for the winter. It's about $7 at Walmart or any major auto parts chain.