New Guy, New Bike....

[xzerminator]

Hi Guys,
Im dragging an XZ550 this weekend and really need some info.
Can you please tell me if i really need the airbox flapper door connected?
(this ones been removed)
Also, is the YICS really necessary or worthwhile having connected (its smashed and needs repair)?

as i only have a couple of days to setup the bike i really only have time to get the urgent stuff sorted out, so if that
stuff isnt needed it will save me a heap of time.

thanks in advance!

[Tiger]

 :) Hi and welcome to the ROV family... 8)

YIKES!!!...I run my Vision without the YICS unit, with no problems. Cap off each port at the heads with vacuum caps...VOILA!!

Flapper Door...it is needed!!

Let us know where you are located...we may have someone close by that can help you out... :-\

         8).......TIGER....... 8)

[xzerminator]

thanks....

im in perth, western australia. so i doubt it.

[xzerminator]

heres the bike...

[nwrider]

Now THAT looks like FUN!!!   :)

[starfire]

howdy.... how is that chain drive??? ???

[vadasz1]

Is this for sand flats or uphill dragging?  Looks WICKED!

[funkamongus]

NICE!!!!!!!!!!!!!!

[QBS]

The flapper door and the YICS unit are primarily designed to facilitate street drivability, especially coming off idle.  I would imagine that off road applications don't spend a lot of time coming off idle.  You can probably get by without either item.  Run it and see if it performs in a competive manner and go from there.  But, make damned sure you have an air cleaner on it.  An inline fuel filter would be a wonderful thing also.  Please keep us posted on your progress.  Cheers.

[fret not]

Realize the original carbs are less than optimal.  Mine were recently tested on a flow bench to find they flow about like  26 mm Dellorto carbs.  Bigger carbs will help it go faster and run better.  Unfortunately the available down draft carbs that are good are very expensive.  Get creative and let us know what you come up with.

[xzerminator]

thanks, I think ill leave the flapper and the YICS off then for this weekend....
converting it to chain drive was easier than you might think, but you couldnt really do it properly
without modifing the oil feeds (i just blocked them off with devcon for this thing)

www.dirtdrags.com in case anyone is curious.

[xzerminator]

heeeeeeeeeeeeeeeelp!!

Ok i Desperately need some more help here. racing in 2 days, and dont have very much time off work to do anything.

The carbs are flooding badly.... wont even start unless you disconenct the fuel and let it turn over for a minute or 2 to clear the fuel out.
If you look into the carbs while starting there is way too much fuelling going on.

ive set the float levels to 22mm below the bowl. (20mm for the level, 2mm more to cover the possibility incorrectly fitted drain tubes)
The accelerator pump looks like its working ok.
Is there anything else common to these carbs that could cause overfuelling like this?

im only going to have about 4 hours tomorrow afternoon to work on this bike so if you can tell me anything to look for on these besides the obvious please let me know....

thanks


i should also mention that there is fuel coming out of the overflow drain tubes. what are the places this can come from? does this mean the fuel level is going above
the 22mm mark that i set it up on?

[starfire]

hi needle and seats clean or is the rubber missing ,floats cracked,on my 83 I believe the carbs have a fuel return line from the carbs that goes to the reg/or fuel pump so when carbs r full this return line flows this may be your trouble ...also hit the  links go to Lucky's vision site he has carb info on their and hes got a really good vision repair manual on CD  for sale....... hope that helps

[xzerminator]

Hi,
when you say "the rubber missing" where do you mean?

I have the factory yamaha manual here :)

[starfire]

on the needle and seat that the float is connected to on the tip of the cone should be a little cone rubber piece that could be winkled or missing or dirty hope that helps...... goto go to wrk good luck

[Night Vision]

I don't think many of us have looked down the barrels, while the bike was running, to see how much fuel actually is flowing...
I've always had my airbox top (and tank) on

but, it does sound like your intake needles are stuck (open) and thus the overflow through the drain tubes...

check the floats / needles again, or give a good whack to the carb bodies to see if you can free the intake needles so that they seat
and stop your flooding...

check the obvious... do you have all the jets in ? correct sizes?

[YellowJacket!]

To kind of add to what everyone else is saying, the Vision carbs absolutely need to be as clean as you can get them to work.  If you haven;t disassembled them and dipped them in carb cleaner then that would be a good starting point.  If they sat for any length of time, you're gonna have to dip them...sometimes more than once.  Once they are clean and balanced, they will function quite well.

As for the  airbox, it smmoths out a flat spot around 4000RPM if it is functioning correctly.  There are two types: one with a vacuum actuator and one without.  If you have the one with the vac, make sure it is connected properly and that you have the little disc filter on the carb to the right of where the vac line connects (its a gray plastic disk filter).

If you have the unupdated carbs/airbox, gluing two US nickles on the flapper is sufficient (Don't know what the NZ equivilent is...sorry), but the flapper is apparently very important because these suckers like to breathe a bit more than the fuel flow will allow them too.

The YICS is an ongoing debate.  I say my bike runs and starts much better with a functioning YICS and if I cap my ports off, my bike runs like crap.  YMMV, as others argue that they notice no difference, but I can always tell even when I have the slightest leak.

In your case (time constraint), it would be quicker to cap the ports, clean the carbs and tune/balance it without the YICS.

Thats one unique looking Vision.

David

[QBS]

Do a search on "Needle Valves".  Sounds like you've got trash in in your float needle valves.  Like I said before, inline fuel filters are wonderful things.

[fret not]

Alternate search terms are "float valves", "carburetor fuel float valves", "float valve set", or other similar words and combinations.

Good luck with the event!  We would like a report when it is over.

Make sure you don't have the floats upside down. ;D

[akvision]

Here is some advice...

"Nothing good happens fast."

Take it for what it is worth.