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Post by ccvogel on Jun 12, 2006 14:44:59 GMT -5
I have a 1981 SR500, all stock. I have been able to get it to start and idle properly when dead cold and when hot [within 10 minutes of engine shutoff], but not when warm [within an hour of shutoff].
What enrichment circuit setting [full on, full off, half way in between] do you recommend when attempting to start a warm bike and to keep it from dying?
Feel free to ask me for more details. The starting regimens for this bike are driving me crazy!!!
BTW, I live in Los Angeles CA USA - no real cold weather. Mostly between 60 and 95 deg F all the time.
Thanks,
ccvogel
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Post by wotavidone on Jun 12, 2006 20:00:45 GMT -5
First things first - check your plug and see if you have a nice dark tan colour.
I am assuming:
your idle mixture adjustment is reasonable and the bike idles clean at about 1100 - 1300 revs when warm, with no "choke" (idle enrichment lever).
bike idles reasonably well with full choke when cold, needing only about a minute to warm up enough to start easing off the "choke". Plug newish
Assuming everything mechanically OK, here's how my 78 starts.
Cold:
Full "choke".
Kick down until you're up against compression, use decompression lever to ease it just over compression, and I mean only just over compression.
Let kick starter right up to get a new bite on the ratchet. Give it a seriously good kick. NO THROTTLE. Should start first or second try. Ease off "choke" as idle speed rises. Bike ready to ride when "choke" fully off.
Hot:
If just turned off minutes ago - say to run into Autopro and get yourself a can of chain lube, - Find compression, ease just through it as per above. Get new bite on ratchet. Give it a good full boot, NO THROTTLE. Should start first kick.
Warmish:
Push up hot start button. Then follow procedure for hot start.
If that doesn't work, use about half choke with hot start button off. NO THROTTLE.
When my bike comes up against compression as I'm easing it over, I can put my full 220 pounds on it and barely move the lever.
I use the decompression to move it just past this point. Just enough so that I can shift the motor.
If I go much further than that the little indicator disappears from the cam window and I don't seem to get a full 4 strokes (power stroke, exhaust stroke, induction stroke, compression stroke, ignition of charge before end of kick) to charge the motor and fire it, when I go to start it.
Hope this helps.
Mick.
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Post by tradrockrat on Jun 13, 2006 10:00:04 GMT -5
just as mick said - I start my 78 the same way except I give it throttle when cold. I live in LA as well, so it would seem that this might work for you too. Of course the 80-81 had a different carb...
what most people seem to miss is the hot button when warm. anything else leads to flooding.
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Post by ccvogel on Jun 13, 2006 13:37:46 GMT -5
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Post by wotavidone on Jun 13, 2006 19:56:04 GMT -5
Ah, if it takes 10 minutes to warm up in California weather, its definitely got a problem. Currently ice on the windows in the mornings here, and mine will start and warm up enough for no choke in a minute or 2.
1700 rpm idle seems like a lot. Though anything up to 1500 wouldn't bother me too much. I think someone with an '81 needs to let you know what needles and jets they are using. Especially needle clip position. I suggest that once you are fairly sure you have the needle in the right spot, you need to look at your idle mixture.
Get the bike running and hot, then set the idle around 1100, and wind your mixture screw out until the bike hesitates and starts to slow down, then wind it just back in until the motor just speeds up again. Then reset the idle speed. Do again if the bike speeds up a lot when you set the mixture.
If you imagine that there is a sort of range of idle mixtures from slightly lean to slightly rich in which the bike works OK, what you do by doing this (winding out ) is set the idle mixture on the slightly rich side of the acceptable range. This should help a little with cold starting.
I put a much bigger main jet than standard in my bike, because my plug was coming out white. I then had to drop the needle to get the low range revs working nice. Plug now comes out tan, and even though I'm running a bigger jet the bile uses less fuel.
Funny bikes, but they are well worth the effort. Stick with it.
Mick
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Post by ccvogel on Jun 13, 2006 21:19:07 GMT -5
Mick,
Thanks for the extremely helpful information.
I'll try the idle mixture setting this weekend.
Meanwhile, I'll post an enquiry on this forum about 81 carb settings.
Thanks again,
ccvogel
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