Topic: K1 Kehin Carb Drain Plug - Thread?

[ZTatZAU]

I should be able to find this somewhere around here but, so far, I haven't had any luck.

Can anyone tell me the thread size of the K1 Kehin Carb drain plugs?

I'd like to use 4 barbed hose fittings, in place of the drain plugs, to check my float bowl levels and I'd like to be sure the fittings have the correct metric thread.

I'm pretty sure they're M6 but the thread pitch on my drain plugs, looks finer than the M6-1 barbed fittings I'm seeing on-line.
Anyone know for sure?
Thanks!  ZT

[willbird]

I should be able to find this somewhere around here but, so far, I haven't had any luck.

Can anyone tell me the thread size of the K1 Kehin Carb drain plugs?

I'd like to use 4 barbed hose fittings, in place of the drain plugs, to check my float bowl levels and I'd like to be sure the fittings have the correct metric thread.

I'm pretty sure they're M6 but the thread pitch on my drain plugs, looks finer than the M6-1 barbed fittings I'm seeing on-line.
Anyone know for sure?
Thanks!  ZT

I dug around before and found this thread here...it said M6x.75

http://forums.sohc4.net/index.php?topic=108293.0

[ZTatZAU]

I dug around before and found this thread here...it said M6x.75
http://forums.sohc4.net/index.php?topic=108293.0

Thanks Bill!

So, rather than specifying the number of threads/inch in SAE, are metric threads specified in MM/thread?  I.E., Each M6-.75 thread would be 0.75 mm apart?  Is that correct?

ZT

[willbird]

I dug around before and found this thread here...it said M6x.75
http://forums.sohc4.net/index.php?topic=108293.0

Thanks Bill!

So, rather than specifying the number of threads/inch in SAE, are metric threads specified in MM/thread?  I.E., Each M6-.75 thread would be 0.75 mm apart?  Is that correct?

ZT

Yep you have it correct. It makes the tap drill selection quick and easy for Metric coarse threads like M6x1.0. Just subtract the pitch from the major dia and you get a 5mm tap drill size easily.

[ZTatZAU]

Thanks again WIllbird!
I appreciate the info.
ZT

[jwurbel]

So the m6 x 1 won’t work?

[HondaMan]

So the m6 x 1 won’t work?

Not for the float bowls. They have a finer thread.

[jwurbel]

As usual thanks.

So is there a source for the correct pitch?  I haven’t found one with an internet search.

[ZTatZAU]

So the m6 x 1 won’t work?

Not for the float bowls. They have a finer thread.

I'm fairly certain the M6x0.75 is correct based upon measuring my existing float bowl drain plug.  It sure looks finer than 1.0 mm per thread to these old eyes.  However, I noticed today that 4into1's website lists M6x1.0 as the thread size of their replacement carb drain plugs.

I haven't found any M6x0.75 fittings on-line.
ZT

[CycleRanger]

Many black-powder revolver nipples use M6x.75mm threading and they're shaped to accept a length of hose.
If you're absolutely sure that M6x.75mm is what you need.

[jamesw]

According to Mike Nixon, K3 onward use M6 x .75

Earlier than use a different size.

[ZTatZAU]

Many black-powder revolver nipples use M6x.75mm threading and they're shaped to accept a length of hose.
If you're absolutely sure that M6x.75mm is what you need.

Well, I wouldn't say I'm absolutely sure; but I'm thinking my drain screws are most likely M6x.75.  And those black powder nipples may work fine!  This of course, doesn't seem to jive with Mike Nixon's view.

According to Mike Nixon, K3 onward use M6 x .75
Earlier than use a different size.

I don't really know who Mike Nixon is, but my bike is a 1971 (12/70) K1 and I'm certain that the carbs and drain screws are original.  And the threads on my drain screws look to be finer than 1.0.

ZT

[willbird]

I measured the drain screws from a set of K3 float bowls and they looked like .75mm pitch to me. I have not tried them in my K2 bike.