1978 gs400 idle fuel

[Bsm1729]

Good evening everyone, I’ve been trying to set a bike up for my cubby, not sure how long it sat in storage. I cleaned the carbs and got it running, but I’m have trouble idling. Basically under 1500 rpm it dies, otherwise it runs and rides good. I pulled the carbs back apart and found that the bowl gasket seems to cover the idle jet, which is mounted in the bowl. The book mentions prior to 1977 use the idle fuel screw to adjust mixture, and I tried to look up the bowl gasket for a 1978 and it looks like what I have. I’m just not sure if mikuni used a different method to deliver idle fuel or if I should modify the gaskets. I can turn the idle screws in and out and no change to rpm. So I know that circuit is not suppling fuel. Thank you for any input

[Bsm1729]

This is the current bowl gasket

[Big T]

Describe the method you used to clean the carbs
Because your idle circuit is clogged

[Bsm1729]

Ultra sonic tank. With degreaser and heat, from what I see the gasket is blocking my idle jet and circuit

[GregT]

Not if you've got it the right way round. Put up a pic of the gasket on the bowl please and we'll tell you if it's correct.

[Bsm1729]

This is the gasket sitting on the bowl, it will not fit the other way unless I cut out a spot for the overflow tube, and this way it seems to cover the idle jet, my main question is to I cut and expose the idle jet, is the new gasket just wrong, or did mikuni have a different way of supplying fuel for idle in this carburetor

[Bsm1729]

Online this seems to be the correct gasket for 1978. I’m just going to add the hole and see if this works, but I’m pretty sure who ever rebuilt these carbs before just didn’t thing to check to see if the new parts matched the old ones, thank you for the help guys, I’ll post back to let everyone know it worked out or it didn’t

[Bsm1729]

Ok put a hole and now the bike idles good, any hints for the timing chain tensioner, it will start to rattle, I’ll give it a twist and it stays quiet for a few minutes

[Rich82GS750TZ]

any hints for the timing chain tensioner, it will start to rattle, I’ll give it a twist and it stays quiet for a few minutes

Rebuild it.

https://www.bwringer.com/gs/camchaintens.html

[Bsm1729]

I saw the article about rebuilding it, but it didn’t seem to describe it as a noise problem, just an oil leak. I’m going order the parts and rebuild it but was not sure if I should expect broken components