Topic: K1 petcock rebuild kit?

[Oddjob]

The test confirms sort of that the petrol tap is leaking. However it could also be the fuel in the lines travelling down the lines which is where the petrol is coming from in the container. What the test does confirm is that the float needle isn’t sealing, if it was there’d be no fuel in the bowl.

First off, do the bowl off the tap test and see if the tap is leaking or not. Secondly, fix the needle valve, by any chance did they also come from 4 into 1? If so they are known to be crap. Put the original brass back in if you still have it. Remove a float bowl and turn on the fuel, now gently lift up the float with your finger and when the small needle on the needle valve just starts to compress does the fuel stop or does it carry on dripping? If the later there’s your problem.

[ZTatZAU]

Thanks Oddjob.  I cant disagree with any of the above.

ZT

[HondaMan]

I, too, have seen bad float valves from 4into1 (and sadly, some other non-OEM vendors). I have had good luck with the ones from PartsNmore, though. The bad ones do not have spin-polished valve tips (the sharp end) that are equal to, or 1 degree less than, the angle of the seat in the body of the carb, and/or the seat angle in the brass seat isn't cut on the same axis as the needle itself. The latter was what I found in the 4into1 set that was sent to me with carbs for rebuild: the only way to fix that is to re-cut the seat. A tool bit to do that in a mill costs more than another set of 4 valves from PartsNmore (and about the same as a Honda set of 4)!

In the PD carbs that body can't be changed, so a proper needle (with rubber tips in those carbs) is the only fix then.

[ZTatZAU]

I appreciate the reply HM but my original K1 carbs (not sure if they are PD or not?) were disassembled and cleaned ultrasonically and re-assembled with all the original Honda brass.  I soldered up a leak in one of the floats which tested good before assembly.  Did a clear tube fuel bowl level test and all four were pretty close to the same (1/8-3/16" IIRC) level below the bottom edge of the carb.

I did remove and unplug the #4 pilot jet after my first couple of test rides because the cylinder was cold.  The jet cleaned up nicely and engine ran fine after.  But it was while I was working on the clogged jet that I first noticed, I had to prop up the #4 float to shut off a drip of fuel even though the petcock was turned off.  That's how all this started for me and I jumped into Steve-0's thread.

At this point I'm focused on replacing the 4into1 aluminum crush washers (presumably leaking), with the proper fiber mounting screw washers; once the new fiber washers arrive in the mail.  Hopefully, that will shut off the fuel reliably when the petcock is turned off.  Once that issue is under control, I'll look into any potential float/needle valve problems.

Anyone see a problem with my plan?  Any other suggestions?
ZT

[Don R]

  It seems odd at first that the petcock to tank washers can make the petcock leak through but it is true. I've dealt with the aluminum washers too, they look like a good idea except they don't work.

[bryanj]

The petrol leaks down the threads of the screws into the sediment bowl which is after the cutoff and directly connected to cards. The fibre washers are not standard sizes in that they are twice as thick to be able to be crushed more.
I have had some success with "dowty" type hydraulic washers but they can sometimes leak as well

[ZTatZAU]

  It seems odd at first that the petcock to tank washers can make the petcock leak through but it is true. I've dealt with the aluminum washers too, they look like a good idea except they don't work.

Not exactly sure what it looks like down inside the petcock but with a new viton seal and what looks to be a healthy wave spring washer, I'm pretty sure the fuel is running down the mounting screws.  Waiting anxiously to receive the repop fiber washers I ordered.

I posted the ebay link above.
ZT

[Oddjob]

Just as a matter of interest have you tried to test the tap to see if the alloy washers are actually leaking? Would seem a shame to blame them if they aren't.

[ZTatZAU]

Just as a matter of interest have you tried to test the tap to see if the alloy washers are actually leaking? Would seem a shame to blame them if they aren't.

Well, I did pull the petcock bowl with the lever OFF and there was a steady drip coming down through the petcock screen.  I did not pull the screen and o-ring to put eyes on the crush washers; but have to assume that's what's leaking.
ZT

[Oddjob]

If it’s dripping it’s the washers that are failing to seal. At least you know for sure now.

[ZTatZAU]

  It seems odd at first that the petcock to tank washers can make the petcock leak through but it is true. I've dealt with the aluminum washers too, they look like a good idea except they don't work.

The petrol leaks down the threads of the screws into the sediment bowl which is after the cutoff and directly connected to cards. The fibre washers are not standard sizes in that they are twice as thick to be able to be crushed more.
I have had some success with "dowty" type hydraulic washers but they can sometimes leak as well

If it’s dripping it’s the washers that are failing to seal. At least you know for sure now.

In addition to the proper fiber washers, has anyone who has dealt with this problem considered, or routinely use, some sort of sealant on the petcock mounting screw threads?

If so, what do you recommend?
ZT

[Stev-o]

I appreciate the reply HM but my original K1 carbs (not sure if they are PD or not?)

We call the early carbs "round tops", the K7-8's had PD carbs.  Why are they called PD?!

That said, I hate fuel leaks!! And ethanol

[ZTatZAU]

I appreciate the reply HM but my original K1 carbs (not sure if they are PD or not?)

We call the early carbs "round tops", the K7-8's had PD carbs.  Why are they called PD?!

That said, I hate fuel leaks!! And ethanol

Haha!  I know what you mean!

That said... Do you use any sealant on your petcock mounting screw threads in addition to the fiber washers?
ZT

[Stev-o]

I appreciate the reply HM but my original K1 carbs (not sure if they are PD or not?)

We call the early carbs "round tops", the K7-8's had PD carbs.  Why are they called PD?!

That said, I hate fuel leaks!! And ethanol

Haha!  I know what you mean!

That said... Do you use any sealant on your petcock mounting screw threads in addition to the fiber washers?
ZT

I only replaced the rubber valve gasket and did not use any sealant. 
I considered a light coat of grease, suggested on another thread, but I did not do it.

[ZTatZAU]

^
Thanks Steve!
I hope my new fiber washers show up today.
ZT

[bryanj]

They are called PD cos thats what is stamped on the flange

[Stev-o]

They are called PD cos thats what is stamped on the flange

Got it, thx Bryan