GS 850 cutting out on cross wind

[rthor]

Just wondering if anyone has seen this situation before...While cruising on my GS 850 (in some intense winds), for some strange reason the engine was cutting in and out when the wind was blowing hard on my right side. When I gave it more throttle it would respond but when I held it at a steady speed the rpm would drop off. I believe the problem is air related because while going down-wind and up-wind the engine ran normally. I can't figure it out. The airbox is stock and the carbs don't seem to have any air leaks.
I've never noticed this problem in all the time I've driven this bike.

[KEITH KRAUSE]

Check your float bowl vent lines for correct routing and no kinks or blockages.
They should go up and back and rest along the air box top/sides. 3/16" is your size?
Stock bikes don't generally have this problem but pod filtered bikes will show fuel starvation easily. I assume your air box still has its lid?
Crosswinds create a "vortex" into and across the bowl vent lines and this compromises good venting. Without good venting, the jets can't draw fuel from the bowls easily.

[rthor]

Come to think of it, I believe my vent lines are all over the place. I'll sort this out and see if that improve things. Thanks Kieth, I would definately not have thought of that.

[KEITH KRAUSE]

You don't say what year your 850 is. I'm guessing you have a '79.
The two floatbowl vent lines are at carbs 2 and 4. #2 supplies venting to #1 and #4 supplies venting to #3. Nothing else would cause fuel starvation during crosswinds that I know of.
Just route them as I said before and their ends won't be in the path of a crosswind. Be sure they're the correct size, 3/16", and they're running clear. I don't know if length matters but it could, so be sure they're close to factory length, which is about 18" I believe. That's about all you can do about crosswinds.
My 1000 with pods will hestitate some during crosswinds and there's not anything you can do about it sometimes. With pod filters, you must REMOVE the vent lines or the fuel starvation is real bad. My bike is in great tune and re-jetted correctly and I still get some venting problems during brisk crosswinds as I said. Just temporary.
Only other thing I'll add but may not be a problem in your case, is to be sure your float levels are adjusted correctly and check for good fuel flow from the petcock and through the float needle valves to the bowls. Also check the gas cap vent to be sure it's clean. Only takes a flow problem at one carb to cause your problem.
Sometimes a problem is a little bit of this and a little bit of that and the multiples add up to a real problem. Hopefully, yours is just a vent line issue.
If all the above is good, then it appears you'll just have to live with the temporary problem. I wouldn't know what else to suggest.

[rthor]

It's an 81 model Kieth. Sixty five thousand kilometres and normally runs like a swiss watch. I re-routed the vents up and around the air box and gave the air filter element a good going over. Took a good long ride today and no problems. I'll give the gas cap vent a check as well. As for the floats, that will be my winter project (a complete carb cleaning). For now, the bikes runs pretty darn good.
Thanks again.
:-D

[KEITH KRAUSE]

It's an 81 model Kieth. Sixty five thousand kilometres and normally runs like a swiss watch. I re-routed the vents up and around the air box and gave the air filter element a good going over. Took a good long ride today and no problems. I'll give the gas cap vent a check as well. As for the floats, that will be my winter project (a complete carb cleaning). For now, the bikes runs pretty darn good.
Thanks again.
:-D

OK.
As for cleaning the carbs, if you were going to do that anyway, that's fine. Just don't do it because you think I'm suggesting it. You COULD have a carb issue but it's hard to say. If the crosswinds are strong enough, I think even a completely stock/correctly tuned bike can show some temporary fuel starvation. Nothing you can do about it other than what I said earlier.

[robertbarr]

Similar maddening story

I had the exact same problem with an '82 850, both before and after a thorough carb overhaul & sync. It acted like fuel starvation, or watery gas, but it varied with the direction (angle) of the crosswind relative to the bike. Head-on, it was no problem. Gusty right-angle winds didn't cause any problem. Slight angled crosswinds were the problem.

I had a '79 GS850 that I bought brand new in '79, and it never exhibited this behavior. Of course, it also used VM carbs... not sure if that was the variable.

In any other condition, the bike ran perfectly -- started immediately, idled smoothly, gobs of power above maybe 3 grand... but a crosswind would make it run poorly. I never did figure out the cause.

I sold it and bought a Honda Nighthawk 650, with the exact same story. This bike runs like a watch, close to the ideal midweight bike, but in certain crosswind conditions I actually have to downshift.