Author Topic: XZ400 carbs on an XZ550?  (Read 10264 times)

pinholenz

  • ROV Senior Member
  • ****
  • Posts: 671
  • Love the Light
XZ400 carbs on an XZ550?
« on: May 23, 2013, 05:53:22 AM »
Back in the last decade (2007) Roro posted the following specs about the differences between XZ400 carbs and XZ550 carbs. Can the 400 carbs be used on a 550 with the jets swapped? Any other major differences?

The XZ400 Supplement shows under Carburetor:

Pilot Screw (PS) 3-1/2 +/- 1/2

Other carb Specs:
Main Jet Front 107.5 Rear 110
Main Air Jet 1.8
Throttle Valve #120
Pilt Jet #60
Pilot Air Jet #145
Valve Seat 1.8
Starter Jet #40
Fuel Level 21 +/- 1mm
Float Height 36 +/- 1mm
Idle Speed 1,300 +_/- 50 rpm
Vacuum pressure at idle > 150mm (5.91 in Hg)
Vacuum Sync Difference < 10mm (0.39 in Hg)
Only one '82.5  eXtreme Zen 550

Rikugun

  • Visionary Grand Master
  • *****
  • Posts: 3250
Re: XZ400 carbs on an XZ550?
« Reply #1 on: May 23, 2013, 07:35:04 AM »
Just out of curiosity, why would you do the swap?

I don't know if the venturi's are smaller (much like '82 vs. '83) but that could hurt/help depending on what you're after. Smaller may increase the low end responsiveness but give up power at high RPM's.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

pinholenz

  • ROV Senior Member
  • ****
  • Posts: 671
  • Love the Light
Re: XZ400 carbs on an XZ550?
« Reply #2 on: May 23, 2013, 07:45:33 AM »
I have been offered a pair of XZ 400 carbs as spares and for parts.  Will they just be re-jetted BD34's?
Only one '82.5  eXtreme Zen 550

Rikugun

  • Visionary Grand Master
  • *****
  • Posts: 3250
Re: XZ400 carbs on an XZ550?
« Reply #3 on: May 23, 2013, 04:52:39 PM »
Anyone? Bueller?  :D
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

Prophet Of Doom

  • Contributing Member
  • Visionary Grand Master
  • ****
  • Posts: 2836
  • The really perverted one amongst us
Re: XZ400 carbs on an XZ550?
« Reply #4 on: May 23, 2013, 04:57:38 PM »
My bike came to me fitted with XZ400 carbs re-jetted, and the 550 in a box.  It's nice to have a spare pair so you can maintain them without putting your bike out of action.

They are both BD34 carbs - There's no guarantee that there aren't mods to the housings but they look identical.  The 400 carbs don't come with a fuel pump, and they won't have the vacuum flapper actuator/air bleed filter on the front carb which you may have on your 550.  Jets and emulsion tubes are different. Gasket is listed as different but I couldn't see why.





iain

  • ROV Full Member
  • ***
  • Posts: 240
Re: XZ400 carbs on an XZ550?
« Reply #5 on: May 23, 2013, 05:11:07 PM »
My silver xz runs 400 carbs and it runs great,,

Iain
NZ

Doc Nielsen

  • ROV Full Member
  • ***
  • Posts: 41
  • Riders of Vision .net
    • Doc Nielsen Internet Service & Support
Re: XZ400 carbs on an XZ550?
« Reply #6 on: May 24, 2013, 07:52:46 AM »
Hmm.. Would 400 carbs on a 550 get rid of the stumble and hunting?
I've tried over and over to get my carbs to run just right, and the stumble and hunting just keeps on coming back.

kwells

  • Visionary Grand Master
  • *****
  • Posts: 2876
    • WellsMoto
Re: XZ400 carbs on an XZ550?
« Reply #7 on: May 24, 2013, 11:56:59 AM »
Perfectly cleaned and sync'd carbs will get rid of your stumble.
...a vision is never complete.

www.wellsmoto.com

Rikugun

  • Visionary Grand Master
  • *****
  • Posts: 3250
Re: XZ400 carbs on an XZ550?
« Reply #8 on: May 24, 2013, 04:17:03 PM »
and the hunting may be air leaks....
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

Rick G

  • Visionary Grand Master
  • *****
  • Posts: 6013
Re: XZ400 carbs on an XZ550?
« Reply #9 on: May 24, 2013, 05:24:04 PM »
The 400 carbs will  work, but so will the 550 carbs . you have problems  related to contamination and /or sync. and as Rik said  you may have air leaks. using 400 carbs will not correct this.
« Last Edit: May 26, 2013, 02:00:01 AM by Rick G »
Rick G
Go soothingly on the grease mud, as there in lurks the skid demon
'82.5 Yamaha XZ550 RJ  Vision,
'90 Suzuki VX800, 1990 Suzuki DR350.
'74  XL350   Honda , 77 XL350 Honda, 78 XL350 Honda, '82 XT 200 Yamaha, '67 Yamaha YG1TK, 80cc trail bike

jefferson

  • Contributing Member
  • ROV Senior Member
  • ****
  • Posts: 551
  • Keep them Rollin
Re: XZ400 carbs on an XZ550?
« Reply #10 on: May 25, 2013, 07:45:30 PM »
If the 400 carbs venturi's are smaller than the 550;s then that should help with the stumble and improve driveability. They would still need to be cleaned very well. The larger engine size pulling through the smaller venturi should give a stronger pull on the circuits in the carb. You would lose some top end, but most riding is done well below there.

Jeff

pinholenz

  • ROV Senior Member
  • ****
  • Posts: 671
  • Love the Light
Re: XZ400 carbs on an XZ550?
« Reply #11 on: May 26, 2013, 04:30:05 AM »
Thanks for the feedback  and information- good to go on the XZ400 carbs.

This is slightly OT, but the possibility of smaller venturis on the XZ400 carbs has got me thinking. Treedragon reported that by lengthening  his venturis he had improved performance. Seems like narrower and/or longer would do the same job of increasing the velocity of air moving down through the butterfly over standard setup.

Has anyone tried doing either mod?

Only one '82.5  eXtreme Zen 550

Prophet Of Doom

  • Contributing Member
  • Visionary Grand Master
  • ****
  • Posts: 2836
  • The really perverted one amongst us
Re: XZ400 carbs on an XZ550?
« Reply #12 on: May 26, 2013, 06:37:14 AM »
Who says the venturis are smaller on the 400?  I'm sure they are the identical.

Treedragon lengthened his intake pipe/velocity stack equally on both carbs I think.  Interestingly the 400 has a longer velocity stack on the front cylinder.  It's not clear from the parts fiche drawing, but the front velocity stack is a good cm or two longer, with a slight curve towards the rear.  The rear is the same as the 550.



pinholenz

  • ROV Senior Member
  • ****
  • Posts: 671
  • Love the Light
Re: XZ400 carbs on an XZ550?
« Reply #13 on: May 26, 2013, 07:19:07 AM »
Roro, it has been suggested, not stated.

I have never seen any '83 carbs, or XZ400 carbs for that matter. But a reviewer of the changes to the xz550 '83 carbs said that the combination of the "new 36mm venturis, repositioned pilot jet and timing/volume of the accelerator pump action", helped eliminate stumble.
http://ridersofvision.net/rovforum/index.php?topic=14443.msg131200#msg131200

So, I am curious whether an extended venturi stack/change in venturi diameter could/does help solve  problems on earlier xz550 carbs?

Only one '82.5  eXtreme Zen 550

Tiger

  • Visionary Grand Master
  • *****
  • Posts: 6217
  • Tiger, tiger burning bright...
Re: XZ400 carbs on an XZ550?
« Reply #14 on: May 26, 2013, 07:31:19 AM »
The 400 carbs will  work, but so will the 550 carbs . you have problems  related to contamination and /or sync. and as Rik said  you may have air leaks. using 400 carbs will not correct this.

I'm with Rick on this one. Properly cleaned, set up (with the correct jets, good seals, vacuum hoses, etc) and synced '82 Vision carbs work well, with NO hesitation/stumble 8)

                     8) ....... TIGER .......  8)
Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well-preserved body, but rather to skid in sideways, body thoroughly used up, totally worn out and screaming HOOOOYA lets go again baby !!!!!!

'82 Vision, Pearl Orange finish, lots of up-grades!!!

Rikugun

  • Visionary Grand Master
  • *****
  • Posts: 3250
Re: XZ400 carbs on an XZ550?
« Reply #15 on: May 26, 2013, 09:55:10 AM »
Who says the venturis are smaller on the 400?  I'm sure they are the identical.

Jeff may have missed your post from the 23rd.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

jefferson

  • Contributing Member
  • ROV Senior Member
  • ****
  • Posts: 551
  • Keep them Rollin
Re: XZ400 carbs on an XZ550?
« Reply #16 on: May 26, 2013, 11:44:58 AM »
I haven't really seen anything definitive on if the carb is smaller or not. We would need actual measurements to be sure. The difference if there is may not be much more than a couple of millimeters. The venturi down inside the carb is the part that would be smaller I think. Some body with both carbs laying around would need to get some accurate measurements so we have some hard facts. You might be able to tell if the venturi part numbers were different between the two also.

Jeff

pinholenz

  • ROV Senior Member
  • ****
  • Posts: 671
  • Love the Light
Re: XZ400 carbs on an XZ550?
« Reply #17 on: May 26, 2013, 02:50:28 PM »
Moving  OT again, I have noticed that the removable venturi, (sits just above the butterfly valve and has a slot on one side,) is not a snug fit on my  carbs. When the retaining screw is in place, the venturi sleeve is pushed to one side of the body leaving a small gap at the top edge of the tapered throat. Is that normal?
Only one '82.5  eXtreme Zen 550

jefferson

  • Contributing Member
  • ROV Senior Member
  • ****
  • Posts: 551
  • Keep them Rollin
Re: XZ400 carbs on an XZ550?
« Reply #18 on: May 26, 2013, 03:49:08 PM »
That's the way they all are as far as I know. I wish the fit was better. Manufacturing tolerance was a little off if you ask me.

Jeff

Rikugun

  • Visionary Grand Master
  • *****
  • Posts: 3250
Re: XZ400 carbs on an XZ550?
« Reply #19 on: May 26, 2013, 11:15:53 PM »
That's the way they all are as far as I know. I wish the fit was better. Manufacturing tolerance was a little off if you ask me.Jeff
I concur on all 3 counts.  :)
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

 

Related Topics

  Subject / Started by Replies Last post
1 Replies
929 Views
Last post December 23, 2002, 09:40:19 AM
by XRay_Vision
6 Replies
1768 Views
Last post October 16, 2006, 07:24:19 PM
by Robin Hood
XZ400

Started by gregs656 « 1 2 3 » Board Archives

44 Replies
8098 Views
Last post December 14, 2007, 07:50:59 AM
by QBS
71 Replies
106846 Views
Last post July 20, 2020, 04:08:42 AM
by Prophet Of Doom
27 Replies
7181 Views
Last post September 18, 2015, 07:23:32 AM
by pinholenz