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This needle valve looks OK, right?

  • Thread starter Thread starter matt_gs450
  • Start date Start date
M

matt_gs450

Guest
Hi All,

According to the shop manuals I have, if there is "scoring or pitting" on the needle valve, it and its seat must be replaced. However, the example graphic shows severe pitting. Below you can see what I'm seeing:

needle-jet-scoring-1.jpg
needle-jet-scoring-2.jpg


When I run my fingernail over the marked area, I don't feel anything. But since it's such a pain to remove and disassemble carburetors, I wanted to see what the consensus is on the forum. Replace or don't replace?

FYI, this is for an '81 GS 450T.

Thanks,
Matt
 
Were you having trouble with over flowing carbs? If you have a good petcock this will prevent this. If there is a question of them being good just replace them.
 
Hey Chef...seems as though I'm playing catch up to you on your posts 8-[ Have to go with you on this one also...replace them. It's not worth the hastle of having to do it over again.
 
Hey Chef...seems as though I'm playing catch up to you on your posts 8-[ Have to go with you on this one also...replace them. It's not worth the hastle of having to do it over again.
I'll give you a ten second head start next time:wink:
 
Damn. I was hoping this was OK... There are no carb rebuild kits for this model. I spent a lot of time looking. An OEM needle valve assembly is $38/per-side at alpha-sports. Does that seem about right?

At that price I may gamble and put the carbs back together with the originals...
 
Thanks for the link. Unfortunately mine is a 1981. Those needles are shaped differently than mine. That's a hopeful sign though. I'll keep an eye on eBay for the correct parts.
 
The light grooving I see on that valve tip looks acceptable to me to continue using. It shouldn't be leaking as long as the spring is operating correctly. Is that carb leaking?
 
The light grooving I see on that valve tip looks acceptable to me to continue using. It shouldn't be leaking as long as the spring is operating correctly. Is that carb leaking?

Agree. Doesn't look bad to me.
 
Boy, if that's problematic, I should have replaced them on all my bikes because mine are WORSE. I did not, and all seem to be sealing properly. I know this because once there was a particle holding the valve open and it caused gas to leak out the overflow tube. After removing the particle, no gas leaked out - so I guess it's sealing just fine.
 
Do you have a vacuum pump? Hook it up to the fuel inlet hose/nipple, assemble needle valves and floats, then flip carbs upside-down and give it a pump, See if it holds. You could also do the old stick the straw to your tongue trick if you don't have a pump.
If it won't hold vacuum, it could also be a bad o-ring, not definitely the valve, so check them too.
 
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