Topic: K1 petcock rebuild kit?

[70CB750]

I was experimenting for a while to see if I could make the 4 hole seal out of Viton, so it would be resistant to the ethanol, the problem was the thickness of the sheet, too thin and it leaked and the next size up was too thick for it to fit with the plate over the top. I was planning on seeing if I could plane a small piece of the viton sheet down to the correct thickness but other projects happened and the idea got shelved, still got all the stuff so I may restart it someday.

I tried that too, did not work.  Mainly because the original seal has small rims around holes to seal, it reduces friction of the petcock.  Maybe 3D printing?

On similar note, on the CB900C I noticed the reserve being hard to turn on on my trip Virginia - Detroit.  I decided to use the reserve more often and it helped.

[Oddjob]

I was experimenting for a while to see if I could make the 4 hole seal out of Viton, so it would be resistant to the ethanol, the problem was the thickness of the sheet, too thin and it leaked and the next size up was too thick for it to fit with the plate over the top. I was planning on seeing if I could plane a small piece of the viton sheet down to the correct thickness but other projects happened and the idea got shelved, still got all the stuff so I may restart it someday.

That's ambitious!

Yeah, I had an idea on how to plane the Viton sheet last night, sort of an epiphany, it may work or it may just chew the sheet to bits. I'll test on a small piece that can make 5 seals if the plan works. It doesn't matter so much if it leaves it a little rough, I can turn the untouched side to face the lever, just so long as the thickness is right. I already have a couple made, but as I said they are too thick to fit. Getting the holes correct is also a problem, I even made a metal template to see if that works, which it does in a fashion.

[bryanj]

A lot of work for a part that only costs a few $

[ZTatZAU]

and whilst the bowl leak has stopped you may find that the fuel can all be consumed without switching to reserve...
John

Thanks for your reply, John!

Coincidentally, I took the bike out the other day  and deliberately ran it until I needed reserve.  I was relying on 30 year old muscle memory to switch to reserve at the slightest hint of fuel starvation rather than waiting for everything to quit before going to reserve.  I remember wondering if the slight miss or burble I felt was really the beginning of no fuel flow but now I'm not so sure.

I'll try starting and going for a ride in the ON position and see what happens.  Then again, if it does run on ON, it may be the fiber gaskets leaking fuel through he threads as posted above. 

It's supposed to be 60° tomorrow so maybe I'll know more than I do today.

...Yeah...that happens on the PD carbs with the single-hose feed from the tank: it is siphoning the fuel from the pipeline and the other bowls until one of them 'breaks' the suction with a bit of air getting into that one's float valve. It's not unique to the 750: the 550 does it, too, on the later carbs with 1-hose feed.

Your explanation makes perfect sense except this is a K1 750.  I'm not exactly sure what PD carbs are but mine are Kehins marked 7A on the manifold flange and my petcock definitely has two fuel outlets and lines to the carbs.

Could the scenario you described occur on a K1?
ZT

[Oddjob]

A lot of work for a part that only costs a few $

Likely though Bryan that the original seal is made out of Nitrile, so it will suffer with the Ethanol if it is. Maybe someone can test one and see what it's made of. They are about £6 I seem to recall.

[newday777]

I've wondered if the vinton seal for the GL1100 petcock would fit.

https://www.randakks.com/gl1000-gl1100-petcock-repair-kit-included-in-gl1000-and-gl1100-master-kit.html

[Stev-o]

I've wondered if the vinton seal for the GL1100 petcock would fit.

https://www.randakks.com/gl1000-gl1100-petcock-repair-kit-included-in-gl1000-and-gl1100-master-kit.html

It should, details from from the listing:


"Special Petcock Sealing Disk (Reproduction of Honda Part# 16955 268 020 "Valve Gasket" a ubiquitous part used on dozens of Honda models over the years...the Honda part is sporadically "discontinued")
Diameter: 20.18 mm
Thickness: 3mm
4 holes in disk...each with diameter of 6mm"


BTW - it is made of Viton rubber [not vinton]

[Oddjob]

Surely this would be better, cheaper and doesn't waste parts not needed.

https://www.randakks.com/randakks-cbx-petcock-seal-not-included-in-cbx-master-kit.html

[HondaMan]

...Yeah...that happens on the PD carbs with the single-hose feed from the tank: it is siphoning the fuel from the pipeline and the other bowls until one of them 'breaks' the suction with a bit of air getting into that one's float valve. It's not unique to the 750: the 550 does it, too, on the later carbs with 1-hose feed.

Your explanation makes perfect sense except this is a K1 750.  I'm not exactly sure what PD carbs are but mine are Kehins marked 7A on the manifold flange and my petcock definitely has two fuel outlets and lines to the carbs.

Could the scenario you described occur on a K1?
ZT

It does, and on the other "K" bikes with the roundtop carbs, but only a little bit: often the bowls don't all run the same exact depth, so the ones that go low first end up draining the fuel from the line, then from the other carb if its bowl is slightly deeper than the one we're talking about. Most of the time this isn't noticed, the engine just starts stumbling on one cylinder and then Reserve gets flipped ON. With my old SuperHawk, the bowls ran exactly the same (because I was anal about it) so when it hit RESERVE, the engine often just died. I had equal-length hoses routed from the petcock to the carbs on the bike (supposing it made a power difference in my virgin technician days) and it could put me out of gas and dead, in the fast lane of the freeway. Pulling over to Chicago's 4-foot-wide inner lane on a 4-lane expressway with a dead engine made it REAL hard to get back into traffic at rush hour. especially before the 55 MPH speed limit came out.

When I got my first 750 (K1) I really rejoiced over this one feature: when the bowls ran low you could ACCELERATE on the other 3 cylinders while waiting for the fuel to re-arrive in the lean one.

[Oddjob]

I lost the first of the group of riders we had when he went onto reserve on the motorway, the engine just died and a car going over 100mph rear ended him, he was catapulted off the bike and his helmet flew off, he landed on his face and was killed instantly, only 18 years old. The driver who killed him got away with it.   

It was a closed casket funeral due to the horrific injuries he had, his dad never got over identifying him,.

[Stev-o]

Update:  received the genuine Honda valve gasket fairly quick and pulled the tank off the bike.  The old gasket looks good but is a little less flexible than the new one but I see no damage.  I'm guessing I installed the new petcock when I rebuilt the bike about 6[?] years ago after the engine blew.

old one on bottom:



Did not want to open a can of worms by removing the petcock so I just set the tank on my tailgate leaning against the generator, luckily only had a gallon of fuel in there...



It was as easy as removing the old gasket and popping in the new one.  The wavy gasket looked good and provided resistance when assembling the petcock.
Popped the tank back on, fitted the fuel lines and cranked it up, no leak!



Took the time to clean the bike while the tank and seat were off, now time for a ride!

[HondaMan]

Good job!
It only takes 0.01mm (about 0.004") difference to make it leak. The compression seal of the rubber against the face of the petcock lever is only that much.

[ZTatZAU]

The petcock is leaking on my K1 tank, but only when the lever is in the off position....

Just curious Steve, but is your petcock leaking fuel out of the petcock itself?  Or is it simply not shutting off the fuel to the carbs when in the off position?
ZT

The petcock is leaking out of the lever area when turned on, it is still working properly when in the off position. It's an odd issue that I have not seen before, I write it off to the the nasty ethanol fuel.

Hey Steve, I came back to this thread to post what I've learned about my petcock problem.  And I'm not trying to ruffle your feathers on this, and please correct me if I'm mistaken; but I think I quoted your original post accurately.  That's what tuned me into this thread in the first place... I.E. A petcock leaking in the OFF position.

You may wish to go back and edit your OP so as not to mislead anyone else about your petcock problem.

And here...

Has this problem (weeping petcock - when off) fixed itself?  Or is the slow dripping fuel evaporating before it reaches the end of the drain line?  Or am I missing something else?
ZT

I do not have a leaking petcock when in off position.    If I were you and had a leaking petcock after a rebuild, I would spring for a new genuine Honda petcock...

Sorry if I wasn't clear Steve, but here I was referring to my own (weeping petcock - when off) problem... not yours; which I understand is pretty much sorted out now.  Good job!

Appreciate your reply Steve but I don't really think I need a new petcock.

At this point, if I notice any more leaking (through the carbs) with the petcock off, I'm more inclined to use or drain the fuel that's currently in the tank, remove the side hold down plate and lever, and replace the aftermarket 4-hole rubber seal with an OEM seal.  Then see what happens!ZT

Did you replace the fiber sealing washers that are under the screws holding the petcock to the tank? The will cause leaking in the off position into the bowl, then into the carb hoses, filing the carb bowls

Not sure if I used the new washers in the kit or the original fiber washers; but the petcock has been on both the old and new tanks, on and off the bike with gas in it, and was not leaking or weeping gas out the exit ports in the Off position.

And it doesn't seem to be leaking now!  So I'll watch this and if I see a problem will try an OEM rubber seal/valve.
ZT

Stu, Now that I've dug into my petcock again, I need to correct my previous answer.  I remember wanting to use the OEM fiber washers during my rebuild, but after digging in to my old parts, remember now that one of the fiber washers was broken, so I used the crush washers provided in the 4into1 kit... which may not be doing the job.

I've wondered if the vinton seal for the GL1100 petcock would fit.

https://www.randakks.com/gl1000-gl1100-petcock-repair-kit-included-in-gl1000-and-gl1100-master-kit.html

I'll be able to give you some feedback on the viton seal pretty soon.  Here's what I've found...



Here, you can see on the left, the original OEM petcock parts I removed several months ago when the petcock was rebuilt with the 4into1 kit.

As described, while cleaning a clogged pilot jet, I noticed I needed to prop up the float to stop fuel at the needle jet with the petcock turned off.  I also noticed the lever was very stiff and suspected modern fuels had swollen the 4into1 four hole seal.

Surprisingly the seal looked fine and, at this point, I do suspect the fuel is leaking into the bowl via the threads of the mounting screws with the 4into1 crush washers.

The stiff lever, I found, was due to some congealed "Fuel Lube" I thought might be a good idea to use.  Apparently not.  The creamy lubricant had thickened up and congealed to where it was impeding rather than faciltating movement of the lever.

I won't be using the "Fuel Lube" when it goes back together but does anyone use some sort of lubricant on the petcock lever?

and whilst the bowl leak has stopped you may find that the fuel can all be consumed without switching to reserve...
John

I plan to find out soon John.  My plan is to put the petcock back together and see if I can ride with petcock ON with only a reserve amount of fuel in the tank.  If it does, I'll pull the petcock and swap the 4into1 crush washers for some new fiber washers.

Which brings me to the last two things I wanted to mention. First is an ebay seller...

https://www.ebay.com/itm/156435081134

... who claims to sell identical fiber washers, from the oem supplier IIRC.  A bag of 5 for $7 with free shipping in lower 48.  Not bad if they work!  I see OEM Honda seals for $5 - $10 each.  These look right and I have a bag on the way.  If my road test confirms the bike does run with petcock ON with only reserve fuel aboard, I'll change out the washers.

Lastly, as to Oddjob and others brainstorming the four hole viton seals, I can tell you the viton seals from Randakks/Dime City are identical in size and shape to the OEM Honda seal as well as the 4into1 seal. 

Randakks charged $7.80 for a viton seal and $5.01 for OEM Honda seal.  I got one of each.  I'll try the viton seal first and report any problems.

And once again, does anyone lubricate the circumference of lever disk or the inner face of the lever disk with anything?
ZT

[newday777]

I used red rubber grease the last one and no problem so far.

[ZTatZAU]

I used red rubber grease the last one and no problem so far.

'Red Rubber Grease', Thanks Stu!  Is this common stuff, available locally?

And do you only apply it to the circumferential rotational contact area of the lever or do you put a thin layer on the inner flat surface of the disk in contact with the rubber seal?

[Stev-o]

The petcock is leaking on my K1 tank, but only when the lever is in the off position....

Just curious Steve, but is your petcock leaking fuel out of the petcock itself?  Or is it simply not shutting off the fuel to the carbs when in the off position?
ZT

The petcock is leaking out of the lever area when turned on, it is still working properly when in the off position. It's an odd issue that I have not seen before, I write it off to the the nasty ethanol fuel.

Hey Steve, I came back to this thread to post what I've learned about my petcock problem.  And I'm not trying to ruffle your feathers on this, and please correct me if I'm mistaken; but I think I quoted your original post accurately.  That's what tuned me into this thread in the first place... I.E. A petcock leaking in the OFF position.

You may wish to go back and edit your OP so as not to mislead anyone else about your petcock problem.

And here...

Has this problem (weeping petcock - when off) fixed itself?  Or is the slow dripping fuel evaporating before it reaches the end of the drain line?  Or am I missing something else?
ZT

I do not have a leaking petcock when in off position.    If I were you and had a leaking petcock after a rebuild, I would spring for a new genuine Honda petcock...

Sorry if I wasn't clear Steve, but here I was referring to my own (weeping petcock - when off) problem... not yours; which I understand is pretty much sorted out now.  Good job!

I think there is some misunderstanding.   

Once again, my petcock only leaked when it was positioned "on" and motor was running/riding. The new valve gasket solved the leak.   It did not leak when petcock was positioned "off".

[ZTatZAU]

I think there is some misunderstanding....

Once again, my petcock only leaked when it was positioned "on" and motor was running/riding. The new valve gasket solved the leak.   It did not leak when petcock was positioned "off".

Yep!

That's why I suggested you might wish to go back and read/edit your original post!
Or not.
ZT

[Stev-o]

I think there is some misunderstanding....

Once again, my petcock only leaked when it was positioned "on" and motor was running/riding. The new valve gasket solved the leak.   It did not leak when petcock was positioned "off".

Yep!

That's why I suggested you might wish to go back and read/edit your original post!

Done.  Thank you   

[newday777]

I used red rubber grease the last one and no problem so far.

'Red Rubber Grease', Thanks Stu!  Is this common stuff, available locally?

And do you only apply it to the circumferential rotational contact area of the lever or do you put a thin layer on the inner flat surface of the disk in contact with the rubber seal?

Only the lever circle moves.

[ZTatZAU]

I think there is some misunderstanding....

Once again, my petcock only leaked when it was positioned "on" and motor was running/riding. The new valve gasket solved the leak.   It did not leak when petcock was positioned "off".

Yep!

That's why I suggested you might wish to go back and read/edit your original post!

Done.  Thank you

That's cool!   

Only the lever circle moves.

Thanks Stu,  That's the way I did it cause I didn't know what, if anything, would be best on the flat disk against the viton seal.  I just lightly lubed the contact areas of the disk, spring, and cover plate.  And since none of this should be exposed to the rubber seal, I just used a bit of axle grease.

I'm about ready to put 1/2 gallon of gas in it and go for a "petcock mounting screw washer leak" road test.

ZT

[Oddjob]

After checking out the Randakk viton seal and it’s relatively low cost I ended up buying a couple to test.

I use Silicon grease myself, pretty inert with most things.

[ZTatZAU]

EUREKA!  I just completed my "petcock mounting screw washer leak" - road test and if I correctly understand everything that's been discussed here, I have to conclude that the crush washers that 4into1 provides, in lieu of fiber washers in their rebuild kit, are doing their job.

With a 1/2 gal of fuel, I started and left on RES when I got to the end of the block, I switched to RUN.  Within a couple of trips up and down the block, engine started to stutter and miss, then fully died as I continued to roll.  Switched back to RES and the engine came back to life.  So, I'm thinking... All is well.

After checking out the Randakk viton seal and it’s relatively low cost I ended up buying a couple to test.

I use Silicon grease myself, pretty inert with most things.

Thanks Oddjob!  The viton seal, from Randakks, that I just installed seems to be working fine.  As I mentioned above, stacked side by side and one on top of one another, I couldn't see any dimensional differences between the viton seal, OEM seal, or the 4into1 seal.

ZT

[Oddjob]

I’m not sure if that test is good enough tbh, it could still be leaking but not enough to run an engine, a better test would be to remove the fuel bowl and filter and leave some paper under it, or a tub of some kind. Leave it overnight and if it’s dry in the morning then they are working.

[ZTatZAU]

I’m not sure if that test is good enough tbh, it could still be leaking but not enough to run an engine, a better test would be to remove the fuel bowl and filter and leave some paper under it, or a tub of some kind. Leave it overnight and if it’s dry in the morning then they are working.

Valid point Oddjob.

Thanks!  ZT

[ZTatZAU]

I’m not sure if that test is good enough tbh, it could still be leaking but not enough to run an engine, a better test would be to remove the fuel bowl and filter and leave some paper under it, or a tub of some kind. Leave it overnight and if it’s dry in the morning then they are working.

And apparently, Oddjob was correct!  But I didn't need to pull the petcock bowl to find out.  Despite my successful road test (see above), I pulled the drain hoses from the bottom of the four carbs and positioned a container below the left and right carb pairs... Petcock OFF.

Both containers contained fuel the next morning.  So, I am ready to accept the fact that the 4into1 crush washers should be replaced with the fiber washers that are, unfortunately, still on the way.  I will get to that when the washers show up.

What I'm wondering is... why don't my floats shut off the fuel at the needle valves?   They can't all be leaking?  Or even one on each side?  Can they?  Or, do they all leak a bit normally? 

I am meticulous about turning off the petcock on my Sportster because I've had fuel run through the carb.  So I can't really count on that Bendix float and needle jet... can I?

ZT