Topic: 2 opinion questions cb750K.

[Don R]

 I accidentally pulled a brass nipple out of a petcock and pressed it back in with red loctite 24 hours ago. Will it stay in?  Worth the risk?

 Early carb fuel lines with right side petcock, cylinders #1 and #2 fuel line, should they be routed across the carb insulators or airbox rubbers?   I usually go over the airbox rubbers to keep the line cooler but I can't seem to make them flow downward.

[754]

I think brass nipple is held by a taper fit, so if it was very clean, it should hold..
 Not sure on lines , but if there is a hole in the carb rack I think a line psses thru it.

[HondaMan]

There should be a hole in the carb rack for the hose feeding the 2 carbs nearest the petcock. In the early 750 (before the K4) there were 2 such holes, and the upper one is there for the hose feeding the carbs opposite the petcock. The petcock was on both sides of the tank, depending on which year it was.

The main problem associated with running the feed hose for the far carbs across the front of the carbs is: the engine's top-end heat on warm days will boil most USA-blended ethanol-laced fuels while you sit in traffic. This causes carb overflow dribbles under the rear tire (slippery!) and often fouled sparkplugs from fuel percolating up the jets, out of slide control. This makes for dark sparkplugs.

If the hose is not Honda's 5.5mm hose (with the red stripe on it) or the fancy polyethylene ones from Motion-Pro (pricey...) they may tend to pinch shut at the bends by the petcock. If so, go to Ace Hardware and get a little 1" long spring that you can slide into the hose at the bend point to prevent the squish. I've done this numerous times on "cafe'd" 750s where the petcock is so low that it rivals the float bowl height. I've sometimes made copper elbows from 1/4" copper pipe for those, too.

BTW: the rarest carb mounting plates are the ones with 2 holes for the hoses on BOTH sides of the plate. These came out during the K3.

[ekpent]

 As for the brass petcock nipples I have slightly roughed up their surface a little and tapped them back in. Have never heard of one falling out on its own without someone tugging on the gas line. Your loctite may/should make it even stronger.

[Don R]

 Thanks, for clarity that I didn't give, they are 11/69 carbs with no holes in the plate but a dip between 3 and 4.
  The hose is 5.5mm "Honda" fuel line from  4-1. The OD seems a little bigger. It really grabbed the brass, there was no chance of it falling off.
  I thought I was going to have to cut the relatively new fuel line off the nipple. I used old fashioned water pump pliers for the wire type hose clamp to get it out without crushing or burring it. I read here they are great on jets too. I lubed the ID of hose with a bit of silicone grease, it still seems secure.
  Thanks, Don.

[maxheadflow]

Back in the day when these were new, we'd simply tap them back in with a small hammer.  I think heat cycles would loosen them.

[PeWe]

I have got a nipple out when I had to remove hose with some force from the early style petcock with 2 nipples.

I replaced petcock first time. Next time hammered it back in with a metal hammer. I made some marks with a cutter on the brass nipple. But that might remove alu.
No glue used.

It worked anyway.

[Kevin D]

I pulled a brass petcock nipple out with stiffened hose 20? years 40k miles back. I tapped it back in and got new 5.5mm hose. Both the hose and the petcock have been good since then. Oh, the petcock got some new o-rings too, but the fiber washers are original.

[Don R]

I pulled a brass petcock nipple out with stiffened hose 20? years 40k miles back. I tapped it back in and got new 5.5mm hose. Both the hose and the petcock have been good since then. Oh, the petcock got some new o-rings too, but the fiber washers are original.

  I learned the hard way what those washers do. If they leak, the petcock will never turn off. I bought a few sets when I ordered them.

[PeWe]

I pulled a brass petcock nipple out with stiffened hose 20? years 40k miles back. I tapped it back in and got new 5.5mm hose. Both the hose and the petcock have been good since then. Oh, the petcock got some new o-rings too, but the fiber washers are original.

  I learned the hard way what those washers do. If they leak, the petcock will never turn off. I bought a few sets when I ordered them.

My fibers were too tight to fit the M6 screws. Had to use an M6 tap into the washer.

[Don R]

I pulled a brass petcock nipple out with stiffened hose 20? years 40k miles back. I tapped it back in and got new 5.5mm hose. Both the hose and the petcock have been good since then. Oh, the petcock got some new o-rings too, but the fiber washers are original.

  I learned the hard way what those washers do. If they leak, the petcock will never turn off. I bought a few sets when I ordered them.

My fibers were too tight to fit the M6 screws. Had to use an M6 tap into the washer.

I did that also, I feared leakage if I reamed them. lol.