Yamaha Virago 535 problem

[bobul92]

Helo, sorry if i did not create this topic in the right place, i found it hard to browse through the forum most likely because of the internet connection.

So, my girlfriends bike ( Yamaha Virago 535 y.1990) started to run really poor since like a week ago. Most of the time it starts ok but after a few minutes it starts to lose power and cough. The air filter and plugs have been changed recently. 
I will attach a link with the video of the problem, maybe someone has a better idea of whats going on...

 

Link: 

 

[Farangwithaplan]

just at a guess, I'd look at intake. Check for air leaks between the carbs and the engine. Also check carb bowl and float levels and any jet blockages.

[Dexlowe]

I had a Virago (750cc, 1986 model) in Bangkok for many years. I suspect there's some kind of air intake blockage which affected me once, but that's as much as I know. Good luck and look after that gem.

 

PS: Best bike I've ever owned.

[Kinnock]

Yes - agree that it's most likely a carb issue - they look like diaphragm carbs?  A perished diaphragm causing an air leak is one possibility, or blocked jets due to dirt in the fuel tank.

[Kwasaki]

16 hours ago, bobul92 said:

I will attach a link with the video of the problem, maybe someone has a better idea of whats going on...

As said carb tune up and balance wanting a new diaphragm to usually are main problems, sounds like it too.

Edited July 6, 2019 by Kwasaki

[brokenbone]

17 hours ago, Dexlowe said:

I had a Virago (750cc, 1986 model) in Bangkok for many years. I suspect there's some kind of air intake blockage which affected me once, but that's as much as I know. Good luck and look after that gem.

 

PS: Best bike I've ever owned.

ahem, that particular year and size had major issues with the start clutch, any other size or later model is very fine though

Edited July 6, 2019 by brokenbone

[Dexlowe]

1 hour ago, brokenbone said:

ahem, that particular year and size had major issues with the start clutch, any other size or later model is very fine though

Sure did. Noisiest crank up job I've ever seen. When the startrr motor blew I had a devil of a job getting a 2nd hand one, and when I did find one, it cost an arm and a leg. It never did seat in well and I eventually got rid of it. But before that it was a joy to ride.

 

[Isaanbiker]

OP, it sounds like an electrical problem, but could also be carbs.

 

   First, take the spark plugs out and look at the color, it gives you a lot to finally find the culprit.

 

  It could also be a dirty fuel filter, or an ignition cable fires on the chassis. 

 

   Another possibility is the filter at the petcock is very dirty.

 

   1. Open the screws at the carb bowls and see if fuel's running out. If there's fuel, check for vacuum leaks. Use carburetor spray and spray a bit on the carbs where they're attached. If the idling speed goes up, you've got a leak. 

 

  2. If it's not a fuel problem, take the spark plugs out, also the caps that are attached onto the sparks. ( taske both sparks out) hold the cable to minus/chassis and check if the spark is bright blue/violettish.

 

If the spark's good at the cable, try to attach the cap, stick a spark plug in and check again. The spark should be strong enough that you can see it, more blueish.

 

  If you don't have a spark at one cylinder, but you had it without the cap, the cap needs replacement. If you see black marks inside the caps, they need to be replaced. Even when you've replaced the spark plugs, try new ones. Once they're very wet, it can take a long time for them to dry. 

 

 These bikes vibrate often, so please check the spark cables from the coils to your cylinder for little cuts, you can hear it when they unload somewhere at the chassis. 

 

  I've attached a book for this type of Virago, please have a look and report back. Please do the checks first. Cheers

 

  

 

  

 

 

  

 

       

1992 XV535 B.pdf

[johng]

I would  guess at lack of fuel,   is there rust in the petrol tank ?

there is often a filter inside the fuel tank attached to the stop cock..as well as an external fuel filter which can get blocked  if they are ok then check fuel level in the carb float bowl  it should be possible to do that while the carb is in situ by attaching a clear tube ( like for fish tank air pump ) to the overflow pipe then opening a small scew on the  float bowl  the fuel level should be about level with the  join between the main body of the carb and the float bowl.

 

[Isaanbiker]

OP, did you find the problem? If not, there's a great Virago Facebook page where plenty of people will help you.

 

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