loosing power

[Guerrero]

tank is not leaking,that is for sure.have checked that allready.and the gas is not disapearing while bike is just standing in garage :)
I understand that i need to check everithing,but dont know from where to start.i asume,that carbs are now in best shape,there could be.if everithing has been changed,and cleaned properly. :(

[Rick G]

maybe there in the best condition , but when amateurs repair carbs , their not always as  successful as they need to be.

[fret not]

  "Wow, "Prophet of Doom"...That would make an awesome screen name.  :) Is it too late to change mine!?  "

Never too late. ;)

[Guerrero]

i dont think that master,who worked with 5 times  world champ on motorcycle with sidecar for like 10 + years is an amateur.so..
°just he is not familiar with bikes like this.thats why i am asking help here in forum...i thought that for it is made.

[The Prophet of Doom]

Guerrero, did you disconnect the rev limiter wire?
yes I think it would help if you took a video as it hard to visualize your problem otherwise. that is why the forum is here I'm sure people will help you as much as they can, but it is difficult to diagnose problems just using words

[Guerrero]

hehe,prophetofdoom :)
yeah,now when carbs are done,i will try to dc that wire again,forgot about that,and will see what happens next,and hope in these days will take a video,thanks

[Guerrero]

ok.here are few videos.quality of filming is soo bad,and it is really hard to understand something here,but sorry,i dont have some Go Pro.just my pfone,in front pocket

http://www.youtube.com/watch?v=8RH1avdG1H0&feature=youtu.be
http://www.youtube.com/watch?v=wAGonypHRN0&feature=youtu.be
http://www.youtube.com/watch?v=-g_7Wp5yBZc&feature=youtu.be

will try to explain in short-first gear,not going more that 5k rpm,about 20-25 km/h,after all other gears go till 5k,then try to stuck,sometimes looses acceleration at all,but when,and if i manage to get higher than 5,5 / 6k rpm,it flies pretty good.
and has problems to keep constant speed from zero till these 5k rpm,( like loosing power,and closing throttle)

that is the most nearest,what i can explain =)
btw i dc the rpm limiter.cant tell any difference.

to air flapp has been added 1coin.

[Re-Vision]

 Sounds as though you have no power rather than losing power. I'm no mechanic but I wonder if both cylinders are firing?     BDC

[Guerrero]

yeap.both.and spark plugs are good,in right color

[Rick G]

It doesn't matter if you are a world champion  mechanic , the Vision carbs are like no other . They are more like a Weber car carbs than motorcycle carbs  There are a lot of tricks to Vision carbs . Some Visionaries have had good luck doing their own carbs  some have not.
Your bike is running on one cylinder , cut the  rev limiter wire and report back to us.

[Rikugun]

When you start it from cold use your hand to see if the front header pipes and the rear cylinder "Y" pipe get hot at about the same rate.

After a short ride use a spray bottle and spray water on the front header pipes and the rear "Y" pipe. Does the water sizzle/steam the same for the front and rear cylinders?

[Hartless]

if I noticed correctly, in the first video it seems as the acceleration is jumpy. in most of my experiences this means there is some sort of vacuum leak... I didn't notice you saying anything about doing the carb cleaner check for vacuum leaks.
as for not being able to get above 5,000 rpm it sounds like you are indeed only running off of one cylinder. I had this problem after I rebuilt my engine and (I don't even want to admit this) I mixed up the intake and exhaust cams. doh! I doubt that yours are mixed up, but there could be other problems that have the same effect such as faulty tci, spark plug wires, plugs themselves, coils.....etc.

[Guerrero]

i disconnected rev limiter-no change,as i said.probobly it is tci,i dont know,anyway need to get today to electrican,and will tell about that too...oh,im kind of sick of this all...i know that this is good bike,but so many problems with it :( :'(
if i touch pipes,both are warm.maybe just one cylinder turns on/off all the time?when it is under load?

[The Prophet of Doom]

OK your bike starts well so I'd eliminate pilots and vacuum leaks for the time being, and probably TCI

It really does look like a rev limiter kicking in early.  Double check that you did disconnect it (Really, they fail a LOT), Try firing up your bike at night taking it up to 5k and see if you can see any sparks.  You can get shorting to engine or frame from bad insulation on the HT leads sparking to the engine that shows only at high RPMs
This will show OK on the spark plugs as you cease getting ignition over a certain RPM, they will just be a little wet.  You can also check this by taking it up to 5k and sniffing your pipe, if you stop getting ignition at 5k but your fuel is OK it will make your eyes water

Other possibility I can think of is your main circuits are still blocked, but the others are nice and clean. 

[Guerrero]

Hmm.well as you said i disconnected that wire,but from front.it was easier for me(behind speedo)only if it is the right wire?yelow,with black stripe.about in the middle of dash board?i just gave bike to electrician,want to change all wires,because they have not been changed,since birth,and one day my battery was dead,in 15 km.somwhere i guess it went short. After it will be done,ill try what you sayd about sparks.
And still getting about 10-12 l per 100 km:(:(:( kind of expensive

[Guerrero]

ok.i took out air filter and it started to run much better.so my mechanic sayed,that probobly need to change stock ( i dont know how on english it will be,but in carbs 4 things,that i guess let through fuel,or something,any way-the size is 127.5) and need to change to 122 or even 120.then with some adjustments everithing should be good.
Any thought about that?
bike really runs much much better with out air filter( but filter is not the problem,because it is allmost new,so not dirti)

[Rikugun]

Is there a vacuum operated door where air enters the airbox and is it functioning properly?

[Guerrero]

no.mine is manual,without vacuum.

[Rick G]

You have the 1st setup Yamaha used . They did an update  and provided a kit to use the  vacuum operated flapper . Contact Sunburnedaz, he has some spare  air box tops,  with the vacuum operated flapper. I have some spare carb tops with the vacuum fitting  to operate the flapper. i might even have the instruction sheet on how to install them.

There was a field fix , which consisted of  epoxying a nickel to the top of the flapper door . this caused the door to close sooner , providing a richer mixture in part of the RPM range.

[Guerrero]

i allready did epox flapper door some time ago.but that didnt solve problem.now,when i am without air filter,it runs better,cant tell yet about fuel usage