Topic: Hard to start K1

[beemerbum]

My 1971 Ki has become hard to start. It takes a lot of cranking to fire up. Of course choke is on. A squirt of ether in the airbox gets it going pronto. When running it is superb. Runs beautifully with instant response to throttle inputs. Admittedly, it is not run as often as it should probably be. The above happens even with fresh fuel. Plugs appear perfect with a light tan color. Thoughts, suggestions please. Carbs rebuilt by Hondaman several years ago.

[Johnie]

Beautiful K1 there! Since it's easy I would drop the float bowls and pull the emulsifier tube and slow jet from each carb. Check the holes to see that they are clear. Remember if you take the float off your needle will drop. I usually put a white towel under to catch it. Also check the float bowls for crud. Could also check the screen filter on the bottom of the petcock for crud. The bike not running much certainly would have something to do with the issue.

[BenelliSEI]

Gorgeous bike! +1 to jets. I drop them every couple of years. Usually one of the idle (slow speed] jets is plugged. They are so tiny. If you can’t see through it, soak in carb cleaner and blow out with air. Resist pushing a wire or anything else through, it will scratch and destroy the shape. Same on the mains, the jet is large enough to stay clear, but often one or two of the small holes in the emulsion tube plug up. This all leads to poor starting. Once you’ve done it a few times, it only takes 20-30 minutes. Removing the bottom half of the airbox makes access easier. The towel suggestion is brilliant.

I pull all the float bowls off first. Take the floats off the outside carbs and then do the same to the inside. Clean the inside carb jets and put them back together 100%, including floats and bowls. Now complete the outside carbs. Dropping the outside floats makes it easier to see what you are doing on the inside carbs. Space is tight.

Last thing: when pushing out the float pins, be very gentle. It’s easy to break off a post! Don’t ask how I know…….

[HondaMan]

Are you by chance also using the Transistor Ignition?

[scottly]

My 1971 Ki has become hard to start. It takes a lot of cranking to fire up. Of course choke is on. A squirt of ether in the airbox gets it going pronto. When running it is superb. Runs beautifully with instant response to throttle inputs.

Sounds like your choke isn't working properly?

[beemerbum]

Are you by chance also using the Transistor Ignition?

No sir. Stock as a stove.

[beemerbum]

My 1971 Ki has become hard to start. It takes a lot of cranking to fire up. Of course choke is on. A squirt of ether in the airbox gets it going pronto. When running it is superb. Runs beautifully with instant response to throttle inputs.

Sounds like your choke isn't working properly?

Never thought of that. Something to check. Thanks

[newday777]

I agree on checking the jets and emulsion tubes for crud in them.
How's the inside of your tank? A little bit of surface rust can plug the jets and emulsion tubes. I recently cleaned out a K4 tank and carbs on a friend's bike (he bought it new) as it had slight surface rust in the tank and the carbs were plugged a little from the rust and had rust sediment in the bowls. It didn't really look too bad but the carbs showed that there was particles coming off the tank into the carbs.
Use a good bright flashlight to inspect the tank.
This tank only required Evaporust(5 gallon bucket of it is needed to fill the tank full so it gets the top of the tank too, less doesn'twork. Been through trying less....) I let it soak 4 days.

[beemerbum]

Thanks for all the replies. The bike runs like a raped ape once it starts. Wouldn't plugged jets or emulsion tubes prevent strong running once started?

[ekpent]

Does it just start hard when cold on the first start or hard also once its been warmed up and ran.  I would think a clogged slow jet or two would affect the way it runs down the road.

[beemerbum]

Once warm, it fires up immediately. Hard to start only when cold

[newday777]

Once warm, it fires up immediately. Hard to start only when cold

Ohhh. New information....

Are you shutting off the petcock or leaving it on while it is left sleeping neglected unused?

Have you opened the bowls when it is cold to see how much gas is in each bowl? What is the temperature where you keep the bike?

[Prospect]

I have the exact same problem with one of my k1's. Interested in seeing the comments.

[smee]

Petcock clogged? Happened to my K5 when I first got it. Petcock was full of crud and all plugged up so the fuel was draining slowly to the carbs. Once started, problem went away. I ended up rebuilding it and all was fine.

[BenelliSEI]

Thanks for all the replies. The bike runs like a raped ape once it starts. Wouldn't plugged jets or emulsion tubes prevent strong running once started?

At starter motor revs, your’re not creating much vacuum, everything needs to work as it should. At WOT, not so much? Have a look, you might be surprised what you find.

Having said all this, my K1 does not fire instantly on first touch. It usually takes a few prods with full choke and when it starts it likes the choke turned off pretty quick and I keep it at 1500-2000 rpm for a few minutes before riding off. It then starts instantly when warm, no choke.

[newday777]

Once warm, it fires up immediately. Hard to start only when cold

Ohhh. New information....

Are you shutting off the petcock or leaving it on while it is left sleeping neglected unused?

Have you opened the bowls when it is cold to see how much gas is in each bowl? What is the temperature where you keep the bike?

Also, are you running an inline filter below the carb inlet levels???

[beemerbum]

No inline filter. Learned that lesson years ago

[beemerbum]

Petcock clogged? Happened to my K5 when I first got it. Petcock was full of crud and all plugged up so the fuel was draining slowly to the carbs. Once started, problem went away. I ended up rebuilding it and all was fine.

I opened the petcock bowl yesterday. Some pieces of rust crud in the bottom now cleaned out. Problem not solved. Looks like I'm going to have to pull off the carb rack and start looking at jets, emulsifier tubes

Which leads me to this question: For those of us fortunate enough to own multiple SOHC's or any other motorcycles, how do you keep some of them from sitting around and getting this problem?

[BenelliSEI]

You don’t have to pull the rack off the bike. Remove the bottom 1/2 of the air box and lay a towel under the carbs. Reread my earliest post and work from the inside out. I did have to take a nice stubby, flat blade screwdriver and cut off 1/2 the handle to get into the jet slots. The whole operation takes me less than 1/2 hour.

When I store my bikes for the winter I disconnect the fuel line to the carbs, and do the bowls/ jet cleaning. I put a loop of clear hose on the two petcock outlets to see if it’s drooling. In the Spring I drain the gas from the tank (throw it in my wife’s Hyundai). Fresh gas and it starts instantly…….pain in the butt, works every time.

[scottly]

If it there was a fuel delivery problem, like a partially plugged petcock or filter that didn't flow, the problem would be worst at WFO in 5th gear going up-hill, when the motor is using the most fuel, not when cranking the motor over with the starter. Plugged jets would affect the bike's running when warm, not just when it was cold. Plugged emulsion tubes would make the bike run rich. When the motor is cold, it needs a richer mixture to help it get started, which is what the choke does. Have you verified the choke plates are closing all the way yet?

[beemerbum]

I have not. That is next. Thanks

[Kevin D]

Hmmm, just taking a stab here: how are the carb boots and clamps. Carb caps snug?

[Keith]

I would check basics first; plug gaps, point gaps and timing. Check for vacuum leaks. Do before messing with carbs.

[calj737]

If it there was a fuel delivery problem, like a partially plugged petcock or filter that didn't flow, the problem would be worst at WFO in 5th gear going up-hill, when the motor is using the most fuel, not when cranking the motor over with the starter. Plugged jets would affect the bike's running when warm, not just when it was cold. Plugged emulsion tubes would make the bike run rich. When the motor is cold, it needs a richer mixture to help it get started, which is what the choke does. Have you verified the choke plates are closing all the way yet?

I’ve got to say, Scotty, you recommend the most likely and easiest thing [/i]twice[/i]and every other post is chasing a rabbit down its hole. Seems nobody is actually evaluating the logic of their advice versus the symptoms…

[scottly]

If it there was a fuel delivery problem, like a partially plugged petcock or filter that didn't flow, the problem would be worst at WFO in 5th gear going up-hill, when the motor is using the most fuel, not when cranking the motor over with the starter. Plugged jets would affect the bike's running when warm, not just when it was cold. Plugged emulsion tubes would make the bike run rich. When the motor is cold, it needs a richer mixture to help it get started, which is what the choke does. Have you verified the choke plates are closing all the way yet?

I’ve got to say, Scotty, you recommend the most likely and easiest thing [/i]twice[/i]and every other post is chasing a rabbit down its hole. Seems nobody is actually evaluating the logic of their advice versus the symptoms…