1986 xr600r dual carb idle problem

this is the problem. I can get the bike running with the choke on but it does stay running when i give it throttle or take off choke in either setting and will not start with choke off.

the history of the bike is as such. when i bought it i run it for a season with a eradic idle. I took the carbs apart and found that the main idle carb on the left was missing the main primary chrome jet needle. So i put the needle in and then reset the mixture screw back to factory specs according to the manual-1-3/8 turns out. Has anyone dealt with this situation or can recommend some tips. it runs shortly before puttering out.

I took the carbs apart and found that the main idle carb on the left was missing the main primary chrome jet needle. So i put the needle in and then reset the mixture screw

When you bought the bike it was missing the 2nd needle jet!? Wow that's very odd, it sounds like the bike has been tampered with by a moron. :moon: Good luck, your probably going to need it. If the bike dies out when you take off the choke or give it gas then it sounds like it is starving for gas. It also sounds like the carbs have been compromised. I would start by taking them completely apart and doing a thorough cleaning. While they are apart check for proper jetting size, float level and needle position. After that you should be good to go. Also its a good idea to completely drain the gas from the tank and put fresh gas in. :busted:

this is the problem. I can get the bike running with the choke on but it does stay running when i give it throttle or take off choke in either setting and will not start with choke off.

the history of the bike is as such. when i bought it i run it for a season with a eradic idle. I took the carbs apart and found that the main idle carb on the left was missing the main primary chrome jet needle. So i put the needle in and then reset the mixture screw back to factory specs according to the manual-1-3/8 turns out. Has anyone dealt with this situation or can recommend some tips. it runs shortly before puttering out.

1: Plugged pilot jets, and/or pilot circuit passageways.

2: When you installed the new needle, did you get an OEM needle?

3: What is the quality of spark?

4: Compression?

My hybrid XR with the XL600 engine in it was running terrible the other day..I'd adjusted the Spark plug gap incorrectly.As soon as I got that set right it ran perfectly. It was exhibiting all the signs of a bad carb adjustment. I was dreading having to go in there again(sick of carbs) but it was just my lack of ability to read a feeler gauge correctly that was the cause of the popping /assorted rough running /failure to idle correctly etc..

So far this is what i have found, the carb with the choke and only mixture screw(when sitting on bike is on left side, i assume this is the Primary carb). The needle clip was set at 3rd notch from top, when manual states it should be 4th from the top, i changed. Next i checked the secondary carb(sitting on bike, right side). The manual states it should be set in the 2nd groove, but was in 3rd. This was corrected. Next i will check the jets in the bowl and post what i have found, any comments would be appreciated.

I assume you did a thorough cleaning on the carbs when you had them apart? It just sounds to me like a problem on the idle and/or pilot circuit of the primary carb. And yes, the primary carb is on the left (shifter) side from the rider's perspective. It is the only carburetor that has an idle screw and pilot jet. The secondary carb only has a main circuit.

No mention of whether you even bothered to check the plug for the correct gap.Believe me it makes a big difference having that right. The previous owner may have been a complete abortionist and set it to tight ,,Check it and set it correctly if its out of spec.Also...Air cutoff valve..It's made of rubber and is mounted behind a plate on one of the carbs..Check it for pinholes..Also...Metal parts in carbs do wear out..Rekit it ..expensive but may be the only option to rule all possibilities out..

Plug gap was checked, cleaned, gapped. was still within specs

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