'82 carb/airbox upgrade kit?

[PeteN]

Well, besides doing my starter seal for no good reason (see post "quick starter seal question"), I discovered that my bike has not had this kit installed. ?It doesn't seem to have a stumble, but I'm curious, was this a free kit? ?Could I still get one from Yamaha? ?Should I? ?Mine just has a weighted flap in the airbox, no vacuum linkage or anything like that shown in the picture in the kit instructions. ?Thanks again.

[Lucky]

This was a free repair. I doubt that you'll have much luck getting them to do it, or if there are even kits still in existance, but it can't hurt to try right?

[Dave T.]

I haven't seen it yet, but I hear your supposed to glue 2 nickels on the top of it to cure stumble. Try the swap shop or a local junkyard. You'll probably need the front carb top with the vacuum fitting.

If it runs fine, just leave it alone!

Why did you rebuild the starter in the first place? Was it full of oil? I did mine because it had oil in it. I wanted to get the O-rings that go around the end caps of the starter and Yamaha wanted $18 a piece for em'  :o. I just cut them short and glued the ends together with super glue.  ;D

[PeteN]

I didn't rebuild the starter, I only took it apart to put in the seal because it's a "must do" mod.  Unfortunately, I found the almost new starter already had a spring seal.  I probably won't mess with the airbox because it seems to run good.  I'm tempted to cut the whole flapper thing out and make a bigger hole for air to get in.  Any body ever try running individual pod air filters?   But, if I wanted raw power, I wouldn't have bought a Vision.  After an extended period of wild youth, I've finally calmed down a little, at age 40.  I don't need to Hot Rod every vehicle I own anymore.  ::)

[Silver_Bullet]

Pete,
I haven't tried it, but from previous posts, this machine doesn't work well with individual filter pods, at least without the airbox.  Needs the air volume, or some other complicated thing.  I often wondered about the foam airpods situated IN the airbox.  Would neatly eliminate the filter issue and provide the air volume needed.  But I'm sure someone else has thought of that already.

Mark

[Lucky]

The stock (or upgraded) airbox is needed to restrict airflow durring snap throttle operations. I can fix you up if you want with clean carb top & air box (you have the strap right?)

email me..
--Lucky

[Dave T.]

The stock (or upgraded) airbox is needed to restrict airflow durring snap throttle operations. I can fix you up if you want with clean carb top & air box (you have the strap right?)

email me..
--Lucky

Yo Lucky, what's the strap for? Mine doesn't have one. I noticed the airbox seems to rattle around a lot in the midrange when I'm driving it. I stuck weather seal all around the outside of the airbox, it helped a little. ?:P

I noticed the V's airbox has "velocity stacks" on top of the carbs. I'm no expert, but they must serve some purpose.

Here is a pic from the V gallery of a guy who works at WISECO. He did the filter pod mod and said it stumbles pretty bad...

[Lucky]

If you look at the airbox you'll see a tab on each side pointing down. when the airbox is installed, the strap goes on one tab, over the frame, over the topand on to the other tab. it holds it down tight.  you can get the same effect with a bungee, it just won't be as neat.

having stacks above the venturi's helps to straigten out the airflow as it enters the carbs.  this helps make metering of fuel more consistant.

[rick_nowak]

part of vision stumble is caused by the carbs being too big.  bike is set up for high rpm from factory and the airbox mod is an attempt by factory to cheaply limit the amount of air available to the engine at lower rpm's with a sudden large increase like whacking the throttle open.  most modern bikes have constant velocity type carbs that do this as part of the carb design itself.  Yamaha was being a smarty pants and got caught up in their "better idea"  they never used this idea again and neither has anyone else!

[gbranche]

If you look at the airbox you'll see a tab on each side pointing down. when the airbox is installed, the strap goes on one tab, over the frame, over the topand on to the other tab. it holds it down tight. ?you can get the same effect with a bungee, it just won't be as neat.

Aha! So THAT'S what that extra rubber strap was for. I had it left over after reassembling my '83 last year, and couldn't for the life of me remember where it had come from.

 :D

Greg

[Dave T.]

part of vision stumble is caused by the carbs being too big. ?bike is set up for high rpm from factory and the airbox mod is an attempt by factory to cheaply limit the amount of air available to the engine at lower rpm's with a sudden large increase like whacking the throttle open. ?most modern bikes have constant velocity type carbs that do this as part of the carb design itself. ?Yamaha was being a smarty pants and got caught up in their "better idea" ?they never used this idea again and neither has anyone else!

The new Suzuki SV 1000 (fuel injected) has the same carbs, sort of. But they use a SECONDARY throttle valve. I'd like to see those carbs. Get some of those carbs off Ebay and put into the V! Maybe off a Sv650S! ?:o

Fuel injection is the way to go. You need quite an elaborate system to run it though. O2 sensor, fuel pump, injectors, mapable ignition....

Here is some info on FI for the SV:

New generation SV650S with all-new frame, electronic fuel injection and an exciting new look.
Electronic fuel injection system featuring the Suzuki Dual Throttle Valve System (SDTV)- maintains optimum air velocity in the intake tract for smooth low-to-mid rpm throttle response and high torque output. Includes Auto Fast Idle System (AFIS).
New 16-bit ECM provides precise control of ignition timing and injector operation for each cylinder.
Large throttle bodies fed by an 8.5 liter airbox with a flat-panel air filter for easy maintenance.
Pulsed-air injection system (PAIR) reduces emissions.

[rick_nowak]

ok, a new generation of engineers who have never even heard of the vision trying it again.  its still the same air, and it still follows the same rules.  the carbs are too big for good low rpm operation.  fuel injection is the answer but won't happen for vision!

[Silver_Bullet]

I don't know about that!  Come on guys! We've tackled difficult projects in the past!  With all the engineering experience, electrical experience, trouble-shooting experience, we should be able to do most anything!  Oh, forgot about the money needed :o.  Well, anyone willing to start contributing to the "Vision Fuel Injection Fund"?  Maybe we can get tax-exempt status?  Have I been sniffing too much gun cleaning solvent again?

Mark

[Walt_M.]

I have just been thinking about the 'Power Now' mod that some of the big 4 stroke MX bikes are using on their FCR carbs. I was going to put one on my WR400 but was not able to. What it is, is a plate/tab that fits it the carb throat, parallel to the air flow that sort of directs the air to the open portion of the throttle slide at 'part throttle' openings. They are said to work well but I don't know if it would be effective with our butterfly type throttles. Just thinking, and you know what they say, 'a mind is a terrlble thing'.

[Dave T.]

Hey Walt, you have a WR400F? Sweet. I want one too.. ;D Trade ya fer my old XT? I like the sound of em' uncorked and revvin' like a top fuel dragster... ?:o

How is vibration? Is it bad cruisin' down a gravel road in top gear? Say 60 mph? My XT vibrates bad. I don't like it.

[PeteN]

Lucky, Are you talking about the float bowl cover and airbox lid that are part of the mod kit?  And no, I dont have the strap, is that part of the kit?  What does it do besides stabilize the box?

Dave, fuel injected bikes have throttle bodies, not carbs.  The reason they went to the dual butterflys is they had the opposite problem, too responsive!  On the GSXRs that were the first injected Zuks, they had single butterflys, but the throttle response was so abrupt, they could easily unintentionally spin the tire while leaned over in a turn.  Not good, so the put in a vacuum controlled butterfly in parallel, sort of like a CV carb.

I would think that a pair of 39mm FCR down draft carbs like we were running on the older SV650 racers would work great on the Vision.  They have a big accelerator pump which eliminates any bog or stumble, theoretically.

Walt, I don't think a power now would work on a butterfly carb because the slide carb only opens on one side of the bore, while a butterfly opens on both sides.  The power now acts like a part throttle velocity stack by straightening the air through the half of the carb that is open.

Dave, if you think the WR is cool, try a CRF450, it's the best bike in the world.  And with an auto clutch, it's magic!  I hear the 2005 will be fuel injected.

[Walt_M.]

I got the WR used in '99, cost me $3350, bet you can't say THAT about your CRF. But, what I was thinking about the Power Now concept would be 2 wings, one on each opening of the butterfly. I have looked into FCR carbs, thinking of the 37mm ones the 250s use but they are way too expensive.

[PeteN]

I got the WR used in '99, cost me $3350, bet you can't say THAT about your CRF. But, what I was thinking about the Power Now concept would be 2 wings, one on each opening of the butterfly. I have looked into FCR carbs, thinking of the 37mm ones the 250s use but they are way too expensive.

I got my CRF new ('03) in Canada in 8/02 for $4600US, I think it's worth a few extra $.  Canada was a good place to by new dirt bikes, when the exchange rate was better.

The dual power now wings idea just might work, let us know if it does.  I think the 37mm FCRs would be sweet, but kind of hard to justify the expence.