OK Its not a GS.
I have noticed that on my virago the bike seems to misbehave when I ride off. It misses and acts like its running out of gas, and makes no power and doesn't even want to run... but you pull over and usually it will idle fine. And its not always... on the warmer days it never happens, and once it is fully warm it never happens. But that inbetween time when its warm enough to drive off but not fully up to temperature is when it happens. The carbs are clean, the bike starts and runs like a charm most of the time, the jetting is perfect, there is fresh gas in the tank and its not electrical... cos I have never seen electrical problems that cleared up when hot. That leaves one possibility...
Is it possible to have carb icing up on a bike with a short manifold. The virago's carbs are out in the open air, so is the manifold and so is the aribox for that matter. The manifolds are pretty short though, almost the same as GS. The air box boot is also very short. Yesterday was a classic example... it was cold in the morning and the bike didn't misbehave much, the evening was colder and I believe much more humid... and it ran like crap. On sunday when I rode it, it was much warmer and the bike ran like a charm.
Cool.
Srinath.
I have had it with an RZ350 and my CB360 back when I tried to ride through the Canadian Winter in Ontario. One black ice patched intersection stopped that bad idea the hard way.
I put shield ( cardboard ) infront of the motor to stop bad performance in cold conditions.
I believe if the gas is to cold it can't vapourize or somthing onlong that ling.
Yes, I have also heard that if everything seems to be in working order otherwise, you may want to try running lower octane gas. In cold weather, this has an easier time combusting than higher octane fuel.
Well I use 87... lowest there is, and there is another argument in favor of it... The gas stations around here sell 100 times the cheap stuff than the pricey stuff, and so there is less crap in the gas with 87 a lot of people tell me... some of whom own gas stations.
Cool.
Srinath.
I don't know if this will even fix that, but, there's a trick that I was taught by a m/c mechanic to disable the CA emissions stuff by stuffing a ball bearing up one of the tubes. I only remember the trick, but not which tube. Wish I could be of more help.
The bike never has had emissions stuff in it even stock. I rejetted it and it was fantastic from March 03 to Oct 03 after which it works fine on warmer days and is screwed up on colder... and some colder days its fine and on others its miserable.
Cool.
Srinath.
Suppose carb ice is possible. Check the dewpoint, and see if it is high dewpoint days that are the problem:
http://yarchive.net/air/carb_ice.html
in the 60's hot roder's would take a can and line the inside with copper tubing and hook up the gas line from full pump to the carb. then fill the can with dryice it would super cool the gas and condence the gas making more gas vaporizing in the intake. making more gas in the same size space. this was called a cool can. just ask some dudes about it. see ya.
Perhaps your front cylinder is running cooler than the rear; maybe just enough to throw off fuel vaporization in that in-between temperature range. Even if you don't figure it out, it'll soon get warm enough to make it a moot point (until next November)... :cheers:
Today was bitterly cold... It was ~38 when I left and wet as hell. My breath was turning into clouds right in fornt of my face... I started and let the bike get hot to touch and rode off... and it never happened today. I am just going to let the engine heat build up and take care of itself. The proble I thing is the fact that when you are riding along the bike actually runs cooler than if were idleing. Idle for 10 mins will be hotter than riding for 10 mins, and in the mean time you are vaporizing ~4-5 float bowl fulls in 10 mins per cylinder... so its sucking heat out of it at a phenomenal rate... combination for a ice storm. I'll warm it up befor riding and see if it doesn't happen.
Cool.
Srinath.
Yes, definitely get problems with carb icing on the GS500 in the UK winter.
First off, 38 degrees isn't bitterly cold, that's what we'd call a warm spell in upstate NY this time of year.
It is, however, prime conditions for carb icing if the humidity is high. What happens, as I understand it, is that the pressure drop across the carb causes the air to cool, causing the moisture to condense out and possibly freeze. This is more likely at low throttle settings (higher manifold vacuum) than it is running wide open. When the engine is thoroughly warmed up (and more importantly the carbs get a little heat) it is much less likely to happen. There exist heated carburators that are used on snowmobiles and such. They may be heated by coolant passages on a water cooled motor or electrically. There is a year round Canadian rider on the www.ninja250.net board who has retrofitted his bike with electrically heated carbs because of frequent carb icing. You might want to search that board for some of his experiences.
MarkB
'90 GS500E
'96 Ninja 250
Its like 15 degrees below normal here... we are supposed to be 62 high and 48 low or so, instead we are at 46 high 32 low or some like that.... OK at that point we freeze. Just kidding... keeps the idiots off the road... I'd rather it was in the 30's and 40 all year long.
Cool.
Srinath.
Quote from: MarkBFirst off, 38 degrees isn't bitterly cold, that's what we'd call a warm spell in upstate NY this time of year.
Amen....almost perfect for a backyard bar-b-que (if you're brave enough to go for the mad cows and viral diseased chickens).
Srinath..what about just adding a little Drygas or something similar to your fuel?
I'm further confused because the temps you have problems in are well above freezing.
OK its all about thermal conductivity... humidity bites...
Its was 38 degrees with about 75% humidity. The basic idea is air has very low conductivity, as humidity increases its conductivity increases. 75% humidity will suck the heat off your body at a phenomenal rate, it sometimes feels colder than it was last month when it was 19 degrees and dry as a bone and not much wind. It was fairly windy too but on a bike there is always wind. Humidity makes cold feel colder and hot feel hotter, cos it pumps heat into you or sucks heat off you making you feel the weather literally. Dry gas is for getting rid of water in gas (which is also possible around here) but the sporadic thing on the bike is too dependent on the colder weather for it to not be ice. I also fill gas at the same place all the time. If one time is bad, its all bad if its water/crap in gas.
Cool.
Srinath.