been reading tec tips, but...

[scalded dog]

79 xs special, found some plastic jets, where they screw into the emulsion tubes, went through a lot of carbs over the past ten years, this is the first time, I found plastic jets, also read the tip on over flowing float needles, 80/81, didn't see any tips on the 79, but mine are overflowing, got plastic floats, any help would be appreciated. Thanks 'Dog

[crazy steve]

I've never even heard of plastic jets?! I think I'd replace those with 'standard' brass ones... If your float needles are leaking, they're either dirty (or dirt is getting to them) or worn. It only takes the slightest amount of grit to hold those open...

And if you've switched to plastic floats, use the later float measurement of .906" +/- .020".

[scalded dog]

Thanks Steve, I think I have some 137 brass jets. will look tommorow, cleaned the carbs real well today, maybe that will fix the overflowing float needles. Later 'Dog

[DGXSER]

I also found plastic mains in a set I worked on. Round filed for original jets.

On the platic floats, is the change in height due to the changed shape? Was the actual fuel level consistant, just changed the height of setting based on float shape?

[New2Me]

I also found plastic mains in a set I worked on. Round filed for original jets.

On the platic floats, is the change in height due to the changed shape? Was the actual fuel level consistant, just changed the height of setting based on float shape?

I believe its a combination of weight and fluid displacement

[DGXSER]

Agreed that should read type of float versus float shape. Combination of shape, density of material, volume of the internal chamber, etc..

[kboehringer]

Sorry Old Thread....

79 xs special, found some plastic jets, where they screw into the emulsion tubes, went through a lot of carbs over the past ten years, this is the first time, I found plastic jets, also read the tip on over flowing float needles, 80/81, didn't see any tips on the 79, but mine are overflowing, got plastic floats, any help would be appreciated. Thanks 'Dog

XS11 Folks,
I know this is a very old thread but it the only one I found searching for "PLASTIC MAINS"

I purchased a cheap XS11 "F" last week and found PLASTIC MAINS in its carbs. However, they area a set of '80 carbs based on the recessed mixture screws, tin caps, and non-ported bowls. The mains (Plastic) do not show the MIKUNI Logo so they have to be aftermarket? Guys on FB have seen them before. Seems extremely unlikely these came from Mikuni but I can find NOTHING else on them on the web.

I will replace these with GENUINE MIKUNI but they are pretty unique...



Kurt

[motoman]

Kurt, I'd hang those on wall of man cave for conversation pieces.

[trbig]

Since the grit in our fuel now days will wear the brass jets, I would think plastic would be a "DOH!" moment? Who knows. Somebody thought it was a good idea.

[IanDMacDonald]

Never seen this thread before, but plastic jets as aftermarket bits are quite common at dealerships and small bike shops. Have seen a lot of them in Kehin carbs on my Honda's. Always replaced them with brass.