74 R75/6 with white smoke and no idle

[xpab]

Hi guys,

Been a while since I posted. Trouble free for almost 2 years! But I recently gave my airhead to my dad for him to ride this past season and he posted it up for the winter. When I went to get it going a couple of weeks ago on a warm afternoon, wouldn't start. Thought it might be the usual suspects so I gave it a little love: charged up the battery, drained the tank and refilled with fresh gas, changed the oil, ripped apart the carbs and gave em a fresh clean, changed the plugs and gave it a go. Bike will fire a couple of times with the choke fully on, then I'll get some white smoke and nada. I'm guessing the Dyna elec ignition is fried but thought I'd see what you guys thought might be the suspect before I go drop 200 bucks on a new one, or fit it back to points if I can find them laying around somewhere. Dyna is a couple of years old but hasn't ever given me trouble since it was setup years ago.

Any advice is greatly appreciated. Thanks a ton in advance.

[Duane Ausherman]

Did you do the standard tests? Do you have spark? Does it have fuel? What is the fuel flow to the carbs?

Just because you have some in the tank, that means nothing. Do you have it in the float bowls? That too means little. Remove a plug and squirt in a few cc, not more. Now you have fuel. It should run for a couple of seconds and quit.

Don't ever spend money until you know for sure what the problem is. Rule #1, keep your money in your pocket. If not, give it to me:-)

[xpab]

Hey Duane,

Thanks for the tips. My mistake for not mentioning that I checked for those. It has spark, fuel is running well to the carbs, float bowls are full when I flip the petcock. I'll give it a squirt when I get back to the house and come back with details.

Like I mentioned before, the bike will fire up, but nothing beyond a few pumps of the pistons.

Good advice on the money--that's why I figured I'd check here first!

Thanks again

[daz]

Hey xpab. You went to get the bike on a warm afternoon? Your personals say you're from nyc. Is that New York City? And when was that warm afternoon?

So the flow from the bottom of the carb with the float bowl off, into a container, ran pretty strong for a while? Good luck, stick with Duane's advice until you figure it out.

[xpab]

Hey Daz,

It was about a month ago, but last night it got to bothering me and I couldn't sleep. I keep that bike upstate and it was about 55. I rode another bike up there to store for the winter and figured I'd see if I could get the beemer running. Flow was good, no obstructions.

[Duane Ausherman]

If you know by eye from many tests, then you can just watch the flow and know that it is enough, or not enough. From the petcock it should flow 100 cc in 15 seconds. It should do that on main, or reserve.

What happens if you keep it choked for awhile?

[sterob]

Is the jet in each fuel bowl clear? They can easily block up with crud when a bike sits for a while. You will need a air line to check. If one is blocked, bake will be hard to start.

[xpab]

Yep @sterob, carbs were totally disassembled and and every piece cleaned. Jets are clean as a whistle.

@duane, I didn't measure exact fuel flow but gas would gush and bowls were full every time I took the bowls off.

Thanks guys

[xpab]

Finally made it back to the garage and checked gas flow--running roughly the 100ccs recommended by Duane. Took the carbs apart again in case something had sat up in them over the past few months and they're clean as a whistle. So fuels running properly, carbs are nice and clean, bike has spark, battery is charged up full. When the bike is choked up, not getting any different results on getting it to start up.

Any ideas what else it could be?

[Duane Ausherman]

Yep @sterob, carbs were totally disassembled and and every piece cleaned. Jets are clean as a whistle.

@duane, I didn't measure exact fuel flow but gas would gush and bowls were full every time I took the bowls off.

Thanks guys

That is a good indicator, but not proof of fuel in the combustion chamber. Remove the plugs and drip in a several drips in each cylinder. Try it again and it should run for a second or two and then run out of fuel.

I wish I were there, as this is super simple stuff. We would never go through all of those procedures. Test it and find the error, then fix it. To do all of that to carbs is asking for additional trouble. You can well end up with adding problems to the original one............. or two.