Hey, Everyone I recently purchased a 1986 yamaha virago 700.Today i cranked it let it warm for about 5 min. Then i drove away and it was like it didnt have much power backfiring and pretty much to kind of like it was flooded. any thoughts? Would be appreciated, thanks john
86 Virago 700 Backfiring??
1 - 20 of 20 Posts
Joined
·
11,482 Posts
Could be that it IS flooding-out. How old is the gas? When was the last time it started and ran normally? Could be crud in a float-needle, could be plugged jets or emulsion tubes, could be torn carb-slider boot, could be mice in the airbox..........
Does this help?
Well I was looking at it yesterday. One of the tubes going into the carb it looked like there was a lil gas that had dripped out. The guy i bought it from said the carbs had just been cleaned not long ago. Thanks guys, this is my first bike so im tryin to learn the ropes so thanks for the help.
One more question
Hey guys I was wondering how do you drain the fuel out of it? I think maybe it has some pretty old gas. thanks
Joined
·
7,113 Posts
There is usually a valve called a "pet****" on the tank. You can close off the fuel flow with that. Then take the hose off the tank and get a can set to catch the gas when you re-open the valve. Or, you might be able to take the hose off the carb end and run it right into a can.
low power
OK, Well got that fixed, I had changed a fuel line an it was leaking because the hose clamp wasnt on good. Duh huh lol but now when i take off its really slow. Then at like 3500 rpm it takes off a lil better. Also it has drag pipes on it. And the rear one gets hot pretty fast but the front really doesnt get that hot. And it blows cool air. Any thoughts? Thanks alot guys --Proud Newbie lol
Drag pipes are a bad idea all around. The front one not getting hot is more troubling though. It is not firing correctly. I would check the spark plug for fouling first, and then check the ignition if the plug looks fine. Did the bike run like crap the day you got it?OK, Well got that fixed, I had changed a fuel line an it was leaking because the hose clamp wasnt on good. Duh huh lol but now when i take off its really slow. Then at like 3500 rpm it takes off a lil better. Also it has drag pipes on it. And the rear one gets hot pretty fast but the front really doesnt get that hot. And it blows cool air. Any thoughts? Thanks alot guys --Proud Newbie lol
No, Actually when i got it took off pretty fast. Now its slow off the line. Air is coming out off the pipe tho its blowing hard just not hot?
Air will always blow out of the pipes. It's the combustion that makes it hot, and it looks like there is none in the front cylinder. Running on one cylinder will make it very slow. You need to find out why the front jug is not firing.No, Actually when i got it took off pretty fast. Now its slow off the line. Air is coming out off the pipe tho its blowing hard just not hot?
Hmm?
Ok, I will go out when i get home in like a hour and a half or so. And check the plug and the ignition anything specific I should be looking for? Thanks again for all the help. -- Newbie
Joined
·
11,482 Posts
It's when the air STOPS blowing-out of the pipe that you know for-sure that you broke something.............No, Actually when i got it took off pretty fast. Now its slow off the line. Air is coming out off the pipe tho its blowing hard just not hot?
Look for black fouling on plug. Pull rear plug wire. Connect front plug to wire, but don't install in engine.Turn over engine with the ignition on, plug out and hold metal threaded part of plug on engine and look for a spark when turning motor over. No spark = no combustion. If plug looks good and sparks, time to look at fuel probem in that cylinder.
Solved
Well I found it the plug was fouled I guess. Man it runs like a brand new one now after the smoke got out at least. I just wanted to let you guys know I really appreciate all the help you gave me. --John
Always somethin huh?
Well guys seems there is another problem. I cranked it up and now it backfires from the front cylinder a little bit. For a lil while after I replaced the plug it ran good. Any thoughts?Well I found it the plug was fouled I guess. Man it runs like a brand new one now after the smoke got out at least. I just wanted to let you guys know I really appreciate all the help you gave me. --John
Joined
·
1,609 Posts
Backfire often means an air leak. Check the exhaust pipe's connection to the cylinder, and on down the exhaust to be sure it's solid and that there are no leaks along the way.
Joined
·
7,113 Posts
Something's fouling the plug. Possible sources:
Bad rings letting oil by.
Bad valve stem seals letting oil by.
Bad carb or FI adjustment causing too much fuel to flow into cylinder and fouling the plug.
Maybe not enough fuel causing a hot cylinder, and thus burning the plug.
Weak ignition system not creating hot enough spark to completely combust the fuel.
A compression test would tell you if you had an issue with the rings or the valves. The ignition can be tested by most shops cheaply and quickly. The fueling system can be a true journey of discovery.
Take your plug out and compare it to the chart you'll find on this link:
Spark plug diagnostic chart. - Ford Explorer Ranger Photo Gallery at Serious Explorations
The diagnostic you'll get from that can be very helpful.
Ken's got the right idea, read the plugs and see what they tell you. Sachi is correct about backfiring, though lean conditions can cause it as well. Check with the owner's group, there may be a pilot jet adjustment you can do to the carbs (without removing them if you're lucky) that might help, but if it's running rich it won't. Your plugs will tell you what condition you have. Your front cylinder will typically run a bit colder than your rear due to getting the majority of the air cooling (but the exhaust is not cold).
Joined
·
5,447 Posts
As someone who's owned a Virago ('82 750) you most likely have an air leak in that plumbers nightmare that is the exhaust system. Dump those trumpet shaped basoon looking deals and get some nice straight pipes from Jardine. They make a nice set, sound good too.
1 - 20 of 20 Posts
