Jet block plug function

[davesax36]

Would loose jet block plugs make a bike seem (or actually be) really rich, especially at idle. I know I've got an exhaust leak, but this seems to smell pretty rich even for just idling.

Morley Jet kit,stage 7 needles (3rd clip), stock springs, 152.5 mains, non-drilled slides, Hindle 4-1, a/f screws at 2.5 turns?--set by Danny when he built them.

Throttle response seems fairly good, but maybe little burble when returning to idle after a blip.

 

[Rusty McNeil]

Would loose jet block plugs make a bike seem (or actually be) really rich, especially at idle. I know I've got an exhaust leak, but this seems to smell pretty rich even for just idling.

Morley Jet kit,stage 7 needles (3rd clip), stock springs, 152.5 mains, non-drilled slides, Hindle 4-1, a/f screws at 2.5 turns?--set by Danny when he built them.

Throttle response seems fairly good, but maybe little burble when returning to idle after a blip.

I would guess yes, not having them in place would put the fuel bowls "head pressure" on the jets that are protected by them.

If they are that important though I have never understood why they didn't use a screw plug instead of a loose rubber plug, probably designed by the same guy that designed the oil delivery system

 

[dannymax]

Seems like it would also change the metering of the jets by allowing fuel to be introduced around the loose plug gaps.

Whether it would let in too much or too little fuel....I don't know....:confused2:

 

[maleko89]

Yep, it would run pig rich. Buddy put the PFJ plug in far right side tunnel by mistake and that's exactly what happened. Pig rich at idle and low throttle openings.

They will shrink if they dry up. When I work on the carbs I keep them in a small container of fuel.

 

[sdt354]

I sealed the last jet block I worked on with allen pipe plugs. The hole was just right to tap. I was wondering if I could stop buying the plugs for a while.

 

[maleko89]

Steve, that's very cool. What do those look like?

 

[davesax36]

Yep, it would run pig rich. Buddy put the PFJ plug in far right side tunnel by mistake and that's exactly what happened. Pig rich at idle and low throttle openings.

They will shrink if they dry up. When I work on the carbs I keep them in a small container of fuel.

OK. Looks like I'm flipping these carbs one more time. Hopefully the last time for a long time. I wonder if I can push them back up into the tubes with a pick if I take off the little brass main cap...

 

[maleko89]

OK. Looks like I'm flipping these carbs one more time. Hopefully the last time for a long time. I wonder if I can push them back up into the tubes with a pick if I take off the little brass main cap...

Dave, the brass cap will get you the area of the main jet but the caps are lower and not much clearance to work a pick around the corner.

 

[davesax36]

Ok. I guess I'll have to just take them apart.

 

[jfeagins]

Neat idea.

Example of allen pipe plugs

 

[PATMAX]

Maleko already mentioned that these plugs can get hard and subsequently don't seal fully. Damon F suggests new plugs every carb rebuild. I suppose Allen's would work fine but rubber plugs sure are idiot proof. Considering the source (me) I better stick with factory plugs. Anyone want to offer the tapping and plugging service?

 

[maleko89]

Neat idea.
View attachment 44369
Example of allen pipe plugs

Cool, do they require thread sealant? Does your typical home improvement store carry these? They look like time serts.

 

[davesax36]

Maleko already mentioned that these plugs can get hard and subsequently don't seal fully. Damon F suggests new plugs every carb rebuild. I suppose Allen's would work fine but rubber plugs sure are idiot proof. Considering the source (me) I better stick with factory plugs. Anyone want to offer the tapping and plugging service?

Maybe Danny can do this as an add-on...

 

[dannymax]

Maybe Danny can do this as an add-on...

Doesn't look like it would be too difficult to do but you could only do the pilot jet hole....the main bleed pipe hole has a cross over passage and it looks like that would be blocked by the plug.

 

[davesax36]

I guess it wouldn't keep junk out any better, either, since it's getting pumped in through one of those tiny holes anyway. Still a cool idea.

 

[dannymax]

I guess it wouldn't keep junk out any better, either, since it's getting pumped in through one of those tiny holes anyway. Still a cool idea.

Probly not but it'd be one less thing to go bad.

 

[sdt354]

Steve, that's very cool. What do those look like?

Let me look for it. I'm pretty sure I saved it.
Steve

 

[maleko89]

Thanks, much appreciated!

 

[sdt354]

Thanks, much appreciated!

Correction, it was an 8mm tap I used. A flush allen head like the pipe plugs shown in previous post, would work well I think. This screw might be to high. Sealer is needed for sure. Instead of putting the squeeze on the jet bloc, I put the tap in a vice and turn the jet block.
Now, this is not something I've run yet. But, I'll try it in a set of carbs. Just looking for alternatives. Sometimes a set of carbs needed is held up over these silly plugs and alternatives help out.

 

[jfeagins]

For no more than the OEM rubber plugs cost, I figure any time mine seem loose, I'll simply reorder the OEM's vs risking damaging a jet block.

If a person does do the threaded mod, I don't think any kind of sealant ordinarily used for sealing threads would prove very reliable with gasoline up against it. I'd think, especially the E-fuel, would corrode the sealer out in short order even if it were allowed adequate time to 'cure' before re-assembly.

Anyone know the specifics on thread sealant?