Just because it is easy to do and might help point you in a direction…put an eye dropper of gas down the spark plug hole and a little on the bottom of the spark plug. Put it back in, fuel on, choke on, decomp lever pulled and kick it. Also check that the kill switch on the handle bars is set to “run”.

I just spray crc5-56 past the slide with it open then give her a kick, always works or shows life. Unless you think its flooded in which case open throttle & kick. If its not that then choke should get it going on a closed throttle but choke fixed jet in the bowl cavity has to be clear, poke it or spray against it to see if it exits into the bowl or spray from other way. If 'that' jet is blocked opening the choke only makes a bad situation worse.

Just out of interest, what number is stamped on the top of the carb manifold? Might be worth checking that it is the correct carb for your bike.

ORING
I will eventually buy the OEM part. In the meantime I'm going to try to get it fired after work tonight with a nitrile oring if I can find the correct size.

Starting Spray
I have a bunch of starter spray in my shop but I was freaked out that the spray would cause some sort of detonation inside the engine and harm it. I have been overly cautious with this machine as my buddy's on a budget and I really do not want to break stuff. I like the idea of dripping some fuel into the cylinder I'll give that a shot tonight if I have no luck with the oring/main jet cleaning.

Carb Number
I took a million pictures of the carb body but none of the manifold number. I will attach some random pics to this post of the carb when I was working on it this weekend and take another look tonight for the stamp.

Introspection
This was probably the 50th carb I've cleaned in my short lifetime on this Earth but I am still prone to mistakes. I was staring at the parts fiche of the carb last night and realized I never cleaned the main jet! I pulled the drain plug in the float bowl but I never unscrewed the jet and cleaned it... I am going back to my shop tonight to pull the carb and spray the main jet. Everything else was thoroughly cleaned with compressed carb cleaner and then compressed air (taking care to keep carb cleaner away from the rubber bits while cleaning). I also made sure compressed air and carb spray made it clear through all the passages.

While I am in there tonight I will also pull the pilot again. When I cleaned it on Sunday, I held it up to the light and could see through it.
When my grandfather passed away he left me a lot of his tools. In the set was an oxy-acetylene torch tip cleaner kit... it's a matchbox size square with a bunch of differently sized thin stainless "picks" about 2 inches long. I've been using this for carb cleaning . It's perfect because the sizes are always smaller than the holes they are cleaning (lower risk of making the holes wider).

 

"I took a million pictures of the carb body but none of the manifold number. I will attach some random pics to this post of the carb when I was working on it this weekend and take another look tonight for the stamp."

Thanks.

It should be on the flange, either more or less below the choke lever, or the same place on the opposite side.

OMG that crap in the petcock bowl. Be sure the filter is in the bottom of the petcock where that bowl screws on. Should be a fine copper screen that is cupped and goes into the petcock before you screw on the cup. There should also be a filter on the reserve side of the petcock up in the tank. If my tanks are questionable for integrity I add a custom filter on the copper tube for the petcock so that makes double filtering for the fuel before it gets to the carb. With that gunk you have there I would be adding filtering or your carb will likely plug up quickly.

What Pedalcrazy said. There might be debris piled up in the petcock direct passages from the tank, not uncommon. Turn the valve to on & reserve while with the cup off and position something to catch the fuel and see what runs out.

In the photo with stripped out carb parts , there is no sign of the needle jet being removed .
It should be removed and cleaned out too , as crud can collect there .

hey all, I was finally able to put some more work into this machine this weekend. Still in a no-start condition and I am fairly confident the problem rests within the carb's fuel delivery. I am able to get a fire started temporarily with starting fluid but then the bike dies.

I am thinking for next steps I will smoke test the intake. I am completely stumped as to the issue but I'm confident there isn't enough fuel getting into the cylinder because it doesn't smell flooded after kicking and kicking and kicking.

I cannot get this one fact out of my mind. Weeks ago I had the bike running and it sat for a few weeks.Then I came back and it wouldnt fire but I had not changed anything. That is when I started to dig into the carb.

Carb O-ring
The o-rings I bought from the hardware store did not work. While I was looking up the part number for the o-ring, I realized that I had multiple of these exact o-rings on my XS650. I pulled one off the carb bowl drain screw and it fit perfectly on the RT carb main jet.

Starting Fluid
I sprayed some starting fluid into the cylinder and kicked it -- it definitely wants to start. It burned up the fluid while running for 1-2seconds and then died.

Jets / Casting Numbers
I was unable to find any casting numbers on the carb or manifold. The carb has only 2 casting marks, a symbol on one side and "MIKUNI" on the other.
I pulled the needle jet (used a pen to force it out through the slide area). It appeared clean inside but I still blew it out with carb cleaner and compressed air.

Main Jet = #230
Needle jet = P-0 #188
Float jet = #3.3
Pilot Jet = #45
Float level = .033" measured from centerline

Next Steps
Leak test the carb with smoke
??????? I'm stumped

I watched a video on youtube that was super helpful but has me confused on this particular carb. The gentleman mentions that there is supposed to be a jet in the hole circled in the below photo. My buddy's carb does not have an airjet there, it is straight through the casting.
 

Random pic of the carb "through" the mainjet
 

Floats seem to work properly 


Some pics of the carb on the bike
 
 

 

Forgot the link to the video, at this timestamp he is talking about the air jet - in my buddy's carb there are no threads in that hole (ie no jet, just casting)