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Is our fuel petcock gravity/suction fed by the fuel pump?


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Got the gas tank off and the gas cap is seized on the tank. The fuel gauge float sending unit is completely corroded and the fuel petcock is in pretty bad shape.

 

Can't find the fuel petcock in stock anywhere and not sure if I want to take a gamble and order the rebuild kit from the UK and find out the petcock is too far gone. 

 

Is there an alternative petcock that will fit? It is not vacuum-actuated, the lever seems to be just straight forward tap on - off - reserve. 

PXL_20220118_165444668.jpg

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There was a thread I would guess between 1 and 2 years ago about this very thing on a 3rd gen - the petcock looked about like that and was unserviceable.  After much searching he took a chance on a $25 ebay tank and it had a good one.  As far as I know the petcocks are not interchangeable between generations, so it's hard to know what to do in that situation.  I can't recall who posted that topic - I'll rummage around a bit and see if I can locate it.  There were some ideas in it that might replace the petcock but were never needed after the replacement was found. 

 

Edit:


This thread has a bike just like yours and how the owner solved the petcock problem - had a rusty tank, petcock was toast, NLA from Honda.  But, I don't think this was the one I was looking for.

 

https://www.vfrdiscussion.com/index.php?/forums/topic/96244-rescuing-a-91-vfr750f/page/5/

 

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5 minutes ago, Cogswell said:

There was a thread I would guess between 1 and 2 years ago about this very thing on a 3rd gen - the petcock looked about like that and was unserviceable.  After much searching he took a chance on a $25 ebay tank and it had a good one.  As far as I know the petcocks are not interchangeable between generations, so it's hard to know what to do in that situation.  I can't recall who posted that topic - I'll rummage around a bit and see if I can locate it.  There were some ideas in it that might replace the petcock but were never needed after the replacement was found. 

 

I read that post already. Was hoping enough time passed for alternatives to be available now 😓

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4 minutes ago, DesertKyorugi said:

 

I read that post already. Was hoping enough time passed for alternatives to be available now 😓

 

Here it is - petcock looks just like yours.  Reading the entire thread and looking at the photos, you'll get a flavor of how lucky you were to find such a pristine example.  With so few 3rd gens still around, there just isn't a large enough market to make it worthwhile to manufacture a specific part such as that.  Likely it will be DIY or get lucky to find one (or a whole tank) on ebay.  Let us know how it works out. 

 

https://www.vfrdiscussion.com/index.php?/forums/topic/95638-rescuing-a-92-vfr750f/page/5/

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Finally able to wrestle the carbs off the bike. It was seized solid on the boots. A copious amount of WD40 and choice cuss words were thrown. 

Dropped the bowls and I have to say I have never seen green goo in my years of resurrecting CB750s. Always brown chocolate....

PXL_20220119_004814070.jpg

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So this is a long shot - no mention I could find of how it ever came out.  But, desperate times call for desperate measures . . .

 

On the Aug 16th post in this thread by damionj,

 

https://www.vfrdiscussion.com/index.php?/forums/topic/95638-rescuing-a-92-vfr750f/page/4/

 

Mention is made of placing an order for a petcock from Japan from webike.net  (link embedded in post)

 

https://japan.webike.net/products/24659472.html

 

Note that the part number is one of the two NLA petcocks listed in the fiche from Honda.

 

https://www.partzilla.com/catalog/honda/motorcycle/1991/vfr750f-a-vfr/fuel-tank

 

Maybe send a PM to him and inquire if the part ever arrived.  Who knows maybe the website was not updated for the NLA part, but maybe you get lucky.  Alterantively, contact the site and inquire about availability.  Shipping from Japan is probably steep, but if it's the only place to get it . . .

 

If you post up your findings, some closure on this would probably be of interest to the 3rd gen community as these are a problem that leaves the bike a museum piece unless sorted. 

 

As for green carb gunk, maybe some additives were in the fuel or some weird reaction from the ethanol, or who knows . . .  There are some other threads on here about carb revival and V4 dreams is also a good resource for resurrecting older bikes.

 

https://v4dreams.com/index.html

 

 

 

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13 minutes ago, Cogswell said:

So this is a long shot - no mention I could find of how it ever came out.  But, desperate times call for desperate measures . . .

 

On the Aug 16th post in this thread by damionj,

 

https://www.vfrdiscussion.com/index.php?/forums/topic/95638-rescuing-a-92-vfr750f/page/4/

 

Mention is made of placing an order for a petcock from Japan from webike.net  (link embedded in post)

 

https://japan.webike.net/products/24659472.html

 

Note that the part number is one of the two NLA petcocks listed in the fiche from Honda.

 

https://www.partzilla.com/catalog/honda/motorcycle/1991/vfr750f-a-vfr/fuel-tank

 

Maybe send a PM to him and inquire if the part ever arrived.  Who knows maybe the website was not updated for the NLA part, but maybe you get lucky.  Alterantively, contact the site and inquire about availability.  Shipping from Japan is probably steep, but if it's the only place to get it . . .

 

If you post up your findings, some closure on this would probably be of interest to the 3rd gen community as these are a problem that leaves the bike a museum piece unless sorted. 

 

As for green carb gunk, maybe some additives were in the fuel or some weird reaction from the ethanol, or who knows . . .  There are some other threads on here about carb revival and V4 dreams is also a good resource for resurrecting older bikes.

 

https://v4dreams.com/index.html

 

 

 

 

In the post, eventually Webike canceled Damionj's order. I actually place an inquiry with Webike last night, just waiting for an answer now

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The petcocks are certainly rebuildable, but the problem is that strainer tube, which isn't.  I suppose you might be able to make one...  With the number of vintage bikes being restored, I'm sure there have been attempts to deal with the NLA petcock problem.  A bit of fine stainless steel mesh rolled into a narrow tube ought to do it...

 

But, as briefly discussed on that thread linked above, the plastic strainer on the OEM petcock is needlessly complex for the US-spec bikes (which don't actually use the reserve feature).  So, all you really would need to do is rebuild the petcock using common* viton o-rings, and fashion some kind of strainer and fit it securely into the "reserve" port in the petcock.  (That's the shorter of the two OEM tubes.)

 

* The o-rings are nothing special, but finding the correct sizes might be, unless you just buy a rebuild kit.  There's a company in the UK which sells them.  (The name of which escapes me at the moment...)  And there might be a thread or two on the UK-based Honda VFR Club forum (Bikersoracle) with the o-ring dimensions I found when I rebuilt mine several years ago.

 

Honda used the same petcock assembly on all models of VFR, both those with reserve switches and those without.  All a reserve switch does is switch between two pickup points in the tank, one higher and one lower.  The higher one is "normal" and the lower one is "reserve".  So when your engine starts to sputter, you flip the switch and the petcock allows fuel from the lower pickup to flow from the tank.  With the US-spec bikes the little plastic handle on the petcock (which is hidden under the seat) restricted the rotation of the petcock so that it could only go from "reserve" to "off" (you cannot select "normal" unless you remove the handle).  

 

Ciao,

 

JZH

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You don't have to incorporate a screen to fab reserve capability, is has an in line fuel filter.

 

BUT....   depending on how your tank cleans up,  it would be nice to catch some big stuff.

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18 minutes ago, Captain 80s said:

You don't have to incorporate a screen to fab reserve capability, is has an in line fuel filter.

 

BUT....   depending on how your tank cleans up,  it would be nice to catch some big stuff.

 

I finally got the gas cap to unlock but it is too far gone to be used. The tank is pretty rusty, I am going to use electrolysis to clean it up.

 

The carbs cleaned up nice in the ultrasonic cleaner. Just need to buy #42 slow jets and gaskets. The question now is, to shim or not to shim the needles with stock #130 main?

 

@JZH I will probably go the route of mesh screen covering the whole petcock since it can only used as a on and off under the seat. After cleaning away all the dried up crud, I find the petcock does not stop the flow when switch to off. The click of the ball bearing felt smooth so hopefully it is just the bad gasket. I will drill out the rivets tomorrow and see how it goes. 

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.5mm shim

 

I do it to every one of my V4s that has stock needles.  I'm not proclaiming huge gains, but I am usually running a K&N and some form of aftermarket exhaust, so a little bump in the mid range is welcome.  Stock bikes like it too, just like going up on the pilot.

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26 minutes ago, Captain 80s said:

.5mm shim

 

I do it to every one of my V4s that has stock needles.  I'm not proclaiming huge gains, but I am usually running a K&N and some form of aftermarket exhaust, so a little bump in the mid range is welcome.  Stock bikes like it too, just like going up on the pilot.

 

I am not a redliner kind of rider so I think I will shim it. I always up the pilot, never seen a California bike that's not lean from the factory. Even my 70s CB750Ks were lean

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Carb Hondas were all lean from the factory for the US.  CA versions even more.

 

When I get pilots for my 1990, they will be #42 as well.

 

Pro Tip:  You can just swap the locations of the float bowl covers to defeat the fuel screw limiting tabs,  No grinding or filing required on either part.

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16 minutes ago, Captain 80s said:

Pro Tip:  You can just swap the locations of the float bowl covers to defeat the fuel screw limiting tabs,  No grinding or filing required on either part.

 

Was busy with a NT700 on my lift table that I have been trying to finish so I can get the VFR on it and I haven't taken a closer look at them so pardon my ignorance, what do you mean by limiting tabs?

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PXL_20220122_173005352_MP.thumb.jpg.e83126c2a545bed92148c49f58a9faf4.jpg

Maybe yours have been modified already, or the aluminum cap on the screw has already been removed, but the float bowl and the screw cap both have tabs that limit it's adjustment range from the factory.

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1 hour ago, Captain 80s said:

PXL_20220122_173005352_MP.thumb.jpg.e83126c2a545bed92148c49f58a9faf4.jpg

Maybe yours have been modified already, or the aluminum cap on the screw has already been removed, but the float bowl and the screw cap both have tabs that limit it's adjustment range from the factory.

 

My mixture screws still have the aluminum caps. Is the limiting part a tab on the bowl cover? I had taken off the bowl covers already before unscrewing the mixture screws. Did not notice any limitations. 

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Yes, you can see the matching tab on the float bowl in that pic.  Just swap the bowls to the opposite side and there is no tab on the other side of the bowl.

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1 hour ago, Captain 80s said:

Yes, you can see the matching tab on the float bowl in that pic.  Just swap the bowls to the opposite side and there is no tab on the other side of the bowl.

 

Very cool, I will check it out when the gaskets are here.

 

I ended up buying a used gas tank that comes with a petcock and fuel level sensor. Hopefully, I will have the same luck as Damionj 🤞🏼Will know next Friday

 

What years seat fit on the 91? Just 90-93? Anyone here has a seat that they are no longer using? I don't care if it is beaten up as long as the original foam is decent. I am just going to shave it for my short legs and re-cover it. I would rather not shave the good original seat. 

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3 hours ago, Captain 80s said:

Yes, you can see the matching tab on the float bowl in that pic.  Just swap the bowls to the opposite side and there is no tab on the other side of the bowl.

I thought everyone did that! Lol

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3 hours ago, DesertKyorugi said:

What years seat fit on the 91? Just 90-93?

 

The 1990 - 1993 seat is UNIQUE.

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14 hours ago, Captain 80s said:

 

The 1990 - 1993 seat is UNIQUE.

Oof, that's what I am afraid of. Definitely need to find a spare used seat to shave.

 

Is the slip on exhaust also unique to 90-93?

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