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-   -   Using the choke when starting up a motorcycle (https://www.horizonsunlimited.com/hubb/tech/using-choke-when-starting-up-51636)

Threewheelbonnie 1 Aug 2010 16:56

Quote:

Originally Posted by *Touring Ted* (Post 299374)
True.. But I was trying to put it in a way a novice would understand... The theory is the same.

:innocent:

The Dnepr had one huge advantage, the choke was just a sort of shutter on the air box. Even the bloke who put the thing together after fifteen pints of Vodka couldn't fail to notice if it was working or not. Bings rubber plunger on a cable over the passage into the float chamber thingy on the other hand....

I hate carbs BTW, it's the electrical engineer in me, open loop control, setting by half a turn here, lift the needle a gnats whisker an all that. Give me early 90's Bosch every time :rofl:

Andy

Pigford 1 Aug 2010 22:18

Quote:

Originally Posted by Threewheelbonnie (Post 299363)
* the last bike I saw with a choke (restricted air supply) was a Dnepr, say no more, this is 1930's technology! Most carbed bikes have an enricher circuit.

Ahhhh, my 1983 HONDA XL500R uses a "choke plate" :clap:

The fuel mixture needs enrichening (increasing the fuel quota in the mix) when the motor's cold, because the fuel tends to condense on the cold engine surfaces until at normal running temp! which = lean mixture.

The bikes (with carbs) that need choke for extended periods, are most likely running on the lean side :frown:

Later model carb bikes were purposely designed to run a tad lean - this is to help get thru emissions limits.

Evil Donald 3 Aug 2010 01:23

Quote:

Originally Posted by Threewheelbonnie (Post 299398)
I hate carbs BTW, it's the electrical engineer in me, open loop control, setting by half a turn here, lift the needle a gnats whisker an all that. Give me early 90's Bosch every time :rofl:

Andy

It's all easy once you learn the requisite voodoo. There's a lot to be said for a toolkit consisting of two screwdrivers and a pointy stick.

Anyway...

My KLR likes full choke first thing in the morning, no extra throttle. Once it's running I let it idle until it reaches 100 degrees F on the temp gauge, then open the choke fully. That's just time enough to put on my helmet and gloves in decent weather. Get on the bike, blip the throttle to be sure it's warm enough not to die when I give it some beans, and away I go.

Yes, I know, it's got an enricher, not a choke. It does the same thing, only backwards.

farqhuar 3 Aug 2010 01:27

Quote:

Originally Posted by Evil Donald (Post 299556)
There's a lot to be said for a toolkit consisting of two screwdrivers and a pointy stick.


I'm fascinated to hear what repair functions you use the pointed stick for, Donald! :clap:

Evil Donald 3 Aug 2010 20:11

Quote:

Originally Posted by farqhuar (Post 299557)
I'm fascinated to hear what repair functions you use the pointed stick for, Donald! :clap:

General purpose poking and prodding and pushing and rubbing and scraping and things like that. Pointy sticks are also good for absent head scratching while you figure the best way to apply the screwdrivers.

jeanied1 4 Aug 2010 04:49

Pointy sticks are go!
 
OK guys, so "one pointy stick" just went to the top of my shopping list of essential items - I'm convinced!

I especially like the idea of it as a head-scratching device, as I think I will be doing a lot of that as I get to know my new bike over the coming weeks and months!! :laugh:

Jeanie :mchappy:

Threewheelbonnie 4 Aug 2010 07:57

Quote:

Originally Posted by farqhuar (Post 299557)
I'm fascinated to hear what repair functions you use the pointed stick for, Donald! :clap:

It's for chasing the Demons out of the carb after they've sprinkled the chicken blood in a pentagram and danced naked in the moonlight :rofl:.

The MZ (one tin can full of petrol) I can do, the Bonneville (diaphragms and throttle linkages until the cows come home), I dread anything going wrong worse than the sync, again, again again again. The BMW has something that can be tested with a multimeter so long as you wear wellington boots and don't smoke :biggrin3:

Andy

banditderek 9 Aug 2010 21:07

I've tuned up my XT 600 with K&N filter, dyna-jet stage 2 and a Dep silencer. It requires no choke what-so-ever and idles perfectly from cold, and stays that way all the time. I thought it was running a bit rich, and turned down the mixture screw to a single turn out, so every so often when I'm decelerating with engine braking I hear a little pop (thats lean enough!). I just cant believe how easy it is to start:thumbup1:. My missus has the exact same model, and hers has to be choked all over the neighbourhood! I ride every day though, she rides once a month, that could be the reason:confused1:

*Touring Ted* 9 Aug 2010 23:37

Quote:

Originally Posted by banditderek (Post 300523)
I've tuned up my XT 600 with K&N filter, dyna-jet stage 2 and a Dep silencer. It requires no choke what-so-ever and idles perfectly from cold, and stays that way all the time. I thought it was running a bit rich, and turned down the mixture screw to a single turn out, so every so often when I'm decelerating with engine braking I hear a little pop (thats lean enough!). I just cant believe how easy it is to start:thumbup1:. My missus has the exact same model, and hers has to be choked all over the neighbourhood! I ride every day though, she rides once a month, that could be the reason:confused1:

If it idles that well from cold then it WILL be running rich on the pilot circuit. If you're happy with the way it picks up though, it's obviously not a problem !!

Threewheelbonnie 10 Aug 2010 07:14

Fuel consumption and the colour of the plug will contain the answer to if it's running rich, but if it's getting the extra fuel via the idle circuit or enricher you usually end up going back to stock settings to prove it. I could have thumped the Guzzi mechanic who solved the leaking enricher plungers on my dads (then new) bike by turning down the idle and mixture, they tell you the standard settings for a reason.

Andy


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