:: Yamaha Virago XV Forums That Rock!!! Tech Articles Cylinder dropping out tip

#1:  Cylinder dropping out tip Author: stereoguy Post Posted: Thu Oct 05, 2006 9:40 am

Hi all, I'm new here, I have a 1986 700 virago I bought new in 1986, I'm by no means a bike tech, but I do love to ride my Virago.

I learned something new last fall while working on a problem with the rectifier on my Virago. Problem, rectifier (it actually blew a hole out the side of it). I checked the stator and found it to be good, checked the battery, other than needing a charge it seemed fine, I later replaced it anyway for good measure. I added a second earth ground from the stator, after all of this the rectifier would get extremely hot in a short period of time. I was about to the point of replacing the stator regardless that it checked out. But thought I would check one more thing. I decided that maybe I had a bad connection in the charging system. I started with the connections between the stator and the rectifier, took them apart and used some Deoxit 5 on them to clean them, plugged and unplugged the connection several times. I traced the charging system back to the battery taking apart each connection along the way, spraying it with Deoxit and plugging and uplugging them. After having cleaned all of the connections I found that the rectifier ran warm, it should, but no longer hot.

Now to the beginning, I have been fighting a loosing battle of a dropping rear cylinder for years, numerous carb rebuilds, changed fouled plugs, rebuilt TCI all to no availe. Since I have cleaned these connections I have not dropped a cylinder since. I am going to now make it a part of my routine to clean all of the electrical connections at least once a year. I have gone all summer now without having dropped the cylinder.

My theory on what is happening, all electrical connections will corrode, the corrosion dosn't have to be visible, it may just be a dirty look to the brass. If you get caught in the rain the process can be sped up. Age will also cause these connections to corroded, look dirty causing excessive resistance. With more resistance I don't believe that enough current is always availible to properly fire the cylinder. Also excessive resistance will greatly reduce the life of your stator, battery and rectifier.

Try cleaning your connections if you are having intermittent problems. I use Deoxit, we use it a lot for cleaning potetiometers in stereo equipment. You can use other contact cleaners, do not use WD 40 it is not meant to be a contact cleaner.


#2:   Author: uncleromo Post Posted: Fri Oct 06, 2006 4:37 pm

Good information -- Thanks

#3:   Author: Matthew Post Posted: Wed Oct 25, 2006 5:41 am

yep, also why the Virago needs a good battery.
That situation would amplify that.

#4:   Author: P.O.L. Mafia Post Posted: Wed Oct 25, 2006 7:50 am

you are right on the money.

#5:  Re: Cylinder dropping out tip Author: mark75 Post Posted: Wed Oct 25, 2006 9:22 am

Howdy Stereoguy. Welcome. Good to have you here.
I had the exact situation occur with my 86-700. The only thing I did differently, was remount the reg/rec to the frame with a heat sink(from an old computer) just to make sure it stayed cool.

#6:   Author: packman Post Posted: Sat Dec 30, 2006 5:27 pm

I am glad to see this. I have had the same problem & today I was just pulling connections & cleaning them & it seemed to help some, but didn't cure it. I will give this a shot & hope I can get the bike running for spring.

#7:  Re: Cylinder dropping out tip Author: packman Post Posted: Sat Apr 21, 2007 6:36 am

I have had problems with the rear cylinder dropping out on my wife's '86 700 virago & cleaning the contacts did help. I just found out why the bike would not idle without running the idle adjuster all the way up. The bike had no power when starting out in first gear, but would just jump & take off like a rocket after the rpm's got up a little & ran great on the road at higher speeds. It turn out that one of the carb holders was cracked almos 1/2 way around & was sucking air big time! Ordered new ones on e-bay & will let you know if that is the total fix. I have a picture but am not sure how to attach it.

#8:  Re: Cylinder dropping out tip Author: yamaguzzi Post Posted: Sat Apr 21, 2007 7:17 am

stereoguy: great to hear from you, in addition to the virago there ios a 1981 suzuki gs 850 in the stable. they are notorious for frying reg/rec s . as with the virago we have learned the importaance of adding the extra ground wire as a heat sink, and always a good battery to keep the juice from cooking the stator itself, common sense a lot of good common sense in that head of yours, good to have you. yamaguzzi

#9:  Re: Cylinder dropping out tip Author: slipshine Post Posted: Wed Apr 25, 2007 1:31 am

I've been frustrated for the past year, changing coils, ICM, battery, plugs, carb cleaning, etc... but this tip sounds like it may really help me.

I'm not a mechanic, and have never worked on a bike. How difficult is it to check and clean these connections? Will my mechanic look at me funny if I ask him to check and clean them?

I'm at the end of my rope with the rear cylinder not firing, and almost listed this bike on eBay last weekend. I am so frustrated.

Any addtional information would be greatly appreciated.

#10:   Author: packman Post Posted: Wed Apr 25, 2007 5:45 am

It is easy to clean the connections once the seat is removed. Just pull apart the connections one at a time & spray both male & female parts with a cleaner made for that purpose. Let them dry & check visually & reconnect. There are some connections in the headlight bucket too. I found that the reason my horn didn't work was because one connection in the headlight bucket had come apart. Use a rag to be sure you don't spray stuff over painted parts. I am no mechanic & I did it.

#11:   Author: rayf268 Post Posted: Wed Apr 25, 2007 5:56 am

its the little things that even the expericned back yard wrench over look that are easy, and help your bike stay trouble free .

#12:  Re: Cylinder dropping out tip Author: bridgeendfarm Post Posted: Fri Aug 03, 2007 12:02 am

Thanks for the tips I just bought a 84 1000 virago and the guy said the rear cylinder was missing off and on. He thought it was the coil wire and damaged it by trying to pull it out. While I look for a good price on a coil I will clean the connections. Great board glad I joined you all today

#13:   Author: mark75 Post Posted: Fri Aug 03, 2007 2:02 am

If it was the plug wire(one that attaches to plug from coil), you can just replace the wires, unless you are wanting to replace the coils.
Earlier coil/plug wires just screwed into coil, but later ones were also glued, so it takes a little more work. But it is a way to add spiffy new colored plug wires. Search KB for how-to.
Plug caps just screw on also. There is a resistor in them that can go bad/be replaced.

#14:   Author: Matthew Post Posted: Sun May 17, 2009 10:04 pm


#15:   Author: Arko Post Posted: Fri Aug 14, 2009 10:39 pm

Funny this is the first post I looked at.
I was having the same issue, and just yesterday decided to break down and clean all the connections and clean them, thinking maybe a dirty or faulty connection or coil was the culprit.
I haven't had a chance for a long ride yet, but it didn't act up on the two short runs I took it on.

Maybe this is the fix! Good to hear my logic may be sound.

#16:  Re: Cylinder dropping out tip Author: camos Post Posted: Fri Aug 14, 2009 11:45 pm

There is some satisfaction to be had when occasionally the easy solution is discovered.

Kneel Suckers


#17: Gniark ! Re: Cylinder dropping out tip Author: jimmiegeraghty Post Posted: Wed Apr 28, 2010 12:05 am

Wow, I just had my '83 920 midnight virago in the shop and the guy had just told me the same thing. I told him that I wanted to take it home and look at it myself.

Thank you for your awesome insight into a situation that could have cost me a bundle!


#18:   Author: totallyredvirago Post Posted: Wed Apr 28, 2010 6:29 am

go into your profile and under holidays select none.. it will turn off your vacation.. if your vacation is on you cannot get pm's....dan

#19:  Re: Cylinder dropping out tip Author: jimmiegeraghty Post Posted: Wed Apr 28, 2010 10:40 am

Thank you for that tip.
I am looking forward to getting it on the road and eating up some miles this summer. Tech Articles Cylinder dropping out tip

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