CHOKE does nothing.Puzzled

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Thunderdome74
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CHOKE does nothing.Puzzled

Post by Thunderdome74 »

Hi everyone

I have just finished putting my x together and am busy running the new rings in.
I have a bit of a problem in that i can start it from cold (after nearly running the battery flat)

What i am confused about is the choke is doing nothing.
The plates are opening and closing as they should (checked through airbox)
But it MAKES NO DIFFERENCE TO THE REVS (cold or hot)

The bike runs brilliantly when she is warmed up
Firing on all 6
low revs are great
consistant heat accross all 6

Is it possible this is a symptom of very rich or lean?
Any advice is appreciated as im loathe to pull em

daves79x
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Re: CHOKE does nothing.Puzzled

Post by daves79x »

Your fast idle linkage is likely doing nothing, which to me isn't that bad. But it should open the throttle plates a bit when the choke is applied, and yours obviously is not. I wouldn't sweat that part if it starts fine and warms up easily. Running too fast on choke will blue exhaust pipes instantly.

Dave

Thunderdome74
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Re: CHOKE does nothing.Puzzled

Post by Thunderdome74 »

daves79x wrote:Your fast idle linkage is likely doing nothing, which to me isn't that bad. But it should open the throttle plates a bit when the choke is applied, and yours obviously is not. I wouldn't sweat that part if it starts fine and warms up easily. Running too fast on choke will blue exhaust pipes instantly.

Dave
Thanks Dave, I'm pretty sure thats it. I had the carbs apart so my fault.
They wll come out again for some final fettling after i have bedded the rings in.


Tx mate

Thor

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Re: CHOKE does nothing.Puzzled

Post by CopperCollar »

Don't ask me how I know these things but here are two more things to look at.

Another consideration is one of the carb banks choke linkage is not connected, That chrome looking tab. I had one that came uncoupled.

One more thing to check is that damn choke butterfly spring that allows the plates to flutter, that sometimes gets disconnected.

Mike
When given the choice between being right or being kind; choose kindness. W. Dyer

Thunderdome74
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Re: CHOKE does nothing.Puzzled

Post by Thunderdome74 »

Hi

And we are back, embarrasing story as well

So carbs were apart, put everything back together and verified the choke was operating correctly (fingers in airbox checking flaps)

All good, so i took it for a ride and it was running on 5 cylinders.
Stopped at a mate and he embarrasingly told me to check the spark plug gaps and make them exact to factory specs(DUH)
Mine were way to big

Yup, ran beautifully on 6 after swapping out the gummed up plug and setting the gaps.


Howevere the choke problem persists. Bike starts after just a few swings (choke on ) revs rise for few seconds and then she starts to stumble. If i hold the throttle and close the choke she runs and revs nicely until warmup.

Accelerator pump working perfectly on all 6
Carbs are clean/fuel clean
Bike has 78000km (50k miles)
No smoke
Idles , but sometimes will just die for no reason
( no variance in revs beforehand, sits at 1k and then will die. Fires up immediatly)
When warm the revs tend to hang slightly around 2k
Very high fuel consumption
(full tank got me 120km but it was before setting the plugs correctly)
plugs are a medium to dark brown
12 v at coils
Plugs gapped correctly :oops:
Revs cleanly to 9k
Took it to 170 kph and she had no issues


Does this sound like a too rich fuel/air mixture. Its currently sitting on 2 turns out?
Should i try set it to 1.5?

Anything else i should look at?

I have a cheap chinese carb kit , the brass bits look exact but i didn't swop em out because the needles plunger was a slightly different length.
Should i change out the needle on the slide along with accompaniying emulsion tube?

I know i should spring for randakks kit but its a bit much at the moment consideering our exchange ratio so i am hoping i can do what i can for now

Thanks again for all the help



Thor

daves79x
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Re: CHOKE does nothing.Puzzled

Post by daves79x »

Your plugs should be close to white. You are running way too rich and it's not from the air screw setting. Are you sure your choke plates are opening fully and staying open when running? Are you sure your primary mains and secondary mains are correctly placed? Assume this is a '79 - you didn't say. You also need to gauge the #35 pressed-in jets to see if someone didn't drill them out. If any of your air bleeds are plugged, this will dramatically increase fuel consumption also. You should be getting the equivalent of low-30's to 35 mpg.

Your high idle is likely carb sync issues.

Dave

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Re: CHOKE does nothing.Puzzled

Post by Thunderdome74 »

Thanks again Dave

Yip its a 79.
So befor reading your reply i set the fuel air to 1.5 turns out on all 6.
Now that the plugs are gapped correctly she is running pretty sweet.
i took a long ride yeasterday and i got about 170 kas to a tank before reserve.
The#35's were taken out by me (mike nixons book was used).
I used a self tapping screw to get them out.

When i first dissasembed the carbs the primarys and secondary mains were mixed up(3 carbs had the wrong ones and vise -versa)
So i did SERIOUSLY double and triple check them.

Can i ask what you mean by air bleeds?

She is however running nicely and idleling well.
There is an occasional stumble. Today i fmoved the timing off a tad (it was originally statically timed exactly on the mark)and nearly eliminated the clutch rumble
(i have no ide why this would happen)

Thanks so much for the help. I keep asking here on the forum as there is an amazing bike nearly there! and the knowledge here is awesome.

Learning alot!

Thor

daves79x
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Re: CHOKE does nothing.Puzzled

Post by daves79x »

Your mileage seems pretty good now. The air bleeds are the 3 brass orifices that stick up from the carb body under the dome and slide. There is one air bleed for each circuit, idle jet, primary main jet and secondary main jet. The idle one for number 1 carb is under the air cut-off valve cover. They allow each circuit to 'breathe'.

Dave

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