If the tube from the breather cover is running to the airbox as it should be, its getting some preheated air via its normal function of recycling bypass gasses for reburning. If you have pods this isnt gonna happen.
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There is no such thing as wind chill on an inanimate object.
http://en.wikipedia.org/wiki/Wind_chill
http://en.wikipedia.org/wiki/Wind_chill
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T
tirebiter
Guest
You got me again Grimly. "Windchill" is not the correct description. True the carbs/engine do not "feel" any colder than the ambient air temperature regardless how fast the bike is travelling. Also true that the heat from combustion is being removed from the carbs/engine more quickly the faster I go. The carbs get cooled down closer to ambient temperature at highway speeds than at lower speeds.
Had a chance to try some changes with the carb vent hose. Getting passed and passing cars at 65 MPH did not seem to make any difference. I had not changed the vent hose routing yet but it was about 45 degrees out yesterday. Did not make any changes to the vent hose.
I'm leaning back torwards thinking it's a temperature thing and therefore, mixture related. Will look at the needle height in the air piston/slide and/or try an air jet change and report back.
I'm planning to ride "Little Suzy" all Winter whenever there are dry days and dry roads to ride on.
Had a chance to try some changes with the carb vent hose. Getting passed and passing cars at 65 MPH did not seem to make any difference. I had not changed the vent hose routing yet but it was about 45 degrees out yesterday. Did not make any changes to the vent hose.
I'm leaning back torwards thinking it's a temperature thing and therefore, mixture related. Will look at the needle height in the air piston/slide and/or try an air jet change and report back.
I'm planning to ride "Little Suzy" all Winter whenever there are dry days and dry roads to ride on.
G
GSX1000E
Guest
I run my bikes in all temperatures from 26F-105F degrees and they work just fine. I also know how to jet them for use above 4,000' :wink:
It's possibly still mixture related, but the upsetting of the breather pipes might be the cause, and I might run my own carb bowl breather pipe to a better location, now that's been brought up.
I've found when futzing around with the jetting on the SU, that when it's nearly right it always runs a little better on cold damp days, just like the cars the SUs were fitted to, back in the day, and that was with the factory setup. The trick is to get it just right for 99.99% of the time without having to mess with it any more.
More often than not, when there's a stumble or slight misfire it's because I'm still on the lean side, but the SU is easy to adjust and there's the damper oil option on that too, which you don't have.
I've found when futzing around with the jetting on the SU, that when it's nearly right it always runs a little better on cold damp days, just like the cars the SUs were fitted to, back in the day, and that was with the factory setup. The trick is to get it just right for 99.99% of the time without having to mess with it any more.
More often than not, when there's a stumble or slight misfire it's because I'm still on the lean side, but the SU is easy to adjust and there's the damper oil option on that too, which you don't have.
Steve
GS Whisperer
Both of your vent hoses should be in that metal tab, and they should end before reaching the bottom of the airbox.
Going almost to the ground is way too low, getting into turbulent air.
.
T
tirebiter
Guest
Steve,
I'll see if the left side vent hose will reach. There is only one tab on my air cleaner housing. It's on the right side.
Meanwhile I dug deeper and go ahead Steve, you can say it again, "you told me to go through the carbs entirely back at the beginning". I took out the jet needles and the nylon spacer was underneath the circlip on all 4. It's in the stock location now, above the circlip and a short test drive shows me she seems to like it. I did not touch the mixture screws. I'll know more after several more miles. Certainly does not seem to have done any harm. If anything it's better but like I have mentioned, it's very subtle. Not easy to replicate the symptom, at will.
I defintely felt a lot like Homer Simpson having a big "DOH" moment. All I could think was "all that careful jetting I've done already" DOH !!!
While I had the jet needle out I did some measuring to chart the profile. I have not seen anything like this for these carbs so what else could I do ? Grimly knows what I'm talking about. Apparently the jet needle is a 0.0118" diameter needle. (Bought micrometer before metrifcation became rampant). Not sure what the needle jet diameter is.
The following photos explain the measurements in some detail :
As you can see, I marked the jet needle at approximately 1/8" increments. The jet needle looks fine with no appreciable wear along the biased side that touches the needle jet. There is some polishing on one side of the jet needle which I believe happens within a very few miles of use and and as I understand things, it does not affect the air/fuel ratio.
If anyone is interested, I'll post the jet needle profile chart for a 5D50 needle.
I'll see if the left side vent hose will reach. There is only one tab on my air cleaner housing. It's on the right side.
Meanwhile I dug deeper and go ahead Steve, you can say it again, "you told me to go through the carbs entirely back at the beginning". I took out the jet needles and the nylon spacer was underneath the circlip on all 4. It's in the stock location now, above the circlip and a short test drive shows me she seems to like it. I did not touch the mixture screws. I'll know more after several more miles. Certainly does not seem to have done any harm. If anything it's better but like I have mentioned, it's very subtle. Not easy to replicate the symptom, at will.
I defintely felt a lot like Homer Simpson having a big "DOH" moment. All I could think was "all that careful jetting I've done already" DOH !!!
While I had the jet needle out I did some measuring to chart the profile. I have not seen anything like this for these carbs so what else could I do ? Grimly knows what I'm talking about. Apparently the jet needle is a 0.0118" diameter needle. (Bought micrometer before metrifcation became rampant). Not sure what the needle jet diameter is.
The following photos explain the measurements in some detail :
As you can see, I marked the jet needle at approximately 1/8" increments. The jet needle looks fine with no appreciable wear along the biased side that touches the needle jet. There is some polishing on one side of the jet needle which I believe happens within a very few miles of use and and as I understand things, it does not affect the air/fuel ratio.
If anyone is interested, I'll post the jet needle profile chart for a 5D50 needle.
T
tirebiter
Guest
So now both vent hoses go through the tab on the right side on the back of the airbox as (I guess) it's called on this forum. The one from the 3/4 carbs is a little long so I pulled it up through enough to match the vent hose from the 1/2 carbs. It is not kinked. I checked. Now the end is about 3" higher than it was and both float bowl vent hoses end at the same place about 1 1/2 inches above the bottom of the airbox or about 12 1/2" above the ground.
Test drive at 43 F this afternoon ... no difference. The symptom is still there. Tried pulling out the choke a little and the symptom disappearred 100% ! That did not happen previously, before I put the nylon spacers above the circlip on the jet needles. THERE'S HOPE !
I redadjusted all all the mixture screws 1/2 turn out from best idle when I got back. Amounted to slightly more out than they were. Lost track of exactly where they are at this point. Idle not quite as good now, not as stable, tends to slowly fall off within 15 - 30 seconds as if the plugs are beginning to foul but ...
Will be taking another long enough drive tomorrow night, weather/precipitation permitting. Should tell me a lot.
Test drive at 43 F this afternoon ... no difference. The symptom is still there. Tried pulling out the choke a little and the symptom disappearred 100% ! That did not happen previously, before I put the nylon spacers above the circlip on the jet needles. THERE'S HOPE !
I redadjusted all all the mixture screws 1/2 turn out from best idle when I got back. Amounted to slightly more out than they were. Lost track of exactly where they are at this point. Idle not quite as good now, not as stable, tends to slowly fall off within 15 - 30 seconds as if the plugs are beginning to foul but ...
Will be taking another long enough drive tomorrow night, weather/precipitation permitting. Should tell me a lot.
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