1979 GS850 needle jet replacements

[Guest]

Hi - I was told my needle jets are badly worn and I cannot find any replacements. Does anyone know of any similar jet that might work - even with some modification?

Thanks!

[tkent02]

Who told you this? HAve you looked at them yourself?

[Steve]

Let's also make sure we are talking about the correct part here.

The "needle jet" is also called an "emulsion tube" and is the long, thin tube with several holes in the sides
and has the needle going up and down the middle.

Is that what you are talking about or are you maybe talking about the inlet valves that control the amount of fuel in the bowl?

I just can't imagine how a needle jet would wear out.

.

[tkent02]

Let's also make sure we are talking about the correct part here.

The "needle jet" is also called an "emulsion tube" and is the long, thin tube with several holes in the sides
and has the needle going up and down the middle.

Is that what you are talking about or are you maybe talking about the inlet valves that control the amount of fuel in the bowl?

I just can't imagine how a needle jet would wear out.

.

Not on the VMs. The needle jet is a round hole, about 10m long, pushed into the carb body. It's nearly impossible to replace if you take it out, and I haven't ever seen them wear out. The jet needle is spring loaded to one side so they don't rattle around and wear the jet out.

[Steve]

I guess it's been too long since I have been inside a set of VMs.

.

[tkent02]

Usually you don't see them anyway, they are way up in there and there's no reason to ever take them out, since they don't wear or get clogged or anything.

[BrianS]

Who told you this? HAve you looked at them yourself?

Thank you Steve and Tkent02 for your replies. I took the bike into a local shop as it was running badly. I have overhauled carbs in the past but was just too busy. He found the needle/seats were leaking badly and replaced those. (I speculate that this could have been causing it too run poorly.) And he indicated that the "needle jets" were badly worn (on a scale of 1 to 10 about a 7 he thought). According to him, these are wear items - which are worn down over time by the "jet needles". He is thinking it is going to run way too rich. I thought about getting the pod type air filters to lean it out but would much rather stay with the stock air box. I have looked around a lot on the web and cannot find any needle jets. Different story for 1980 model - those appear to be available. I have not looked at them myself. If I could figure out the original orifice size I might get some made. Or I may just put it back together and try and run it. Also, we are at 3000 to 6000 ft elevation which may exacerbate the running rich issue. Do you all know of the correct orifice size? Is it just a simple orifice or is it more complicated? Would a K and N or similar high-flow filter for the stock airbox help?

Thanks again,
Brian