Hello, My 2006 husqvarna 610 (10600 miles, new cam chain 1k miles ago, new piston/rings 500 miles ago) wont idle steadily. Originally when i got the bike (used) it had standard air-box and JD jet kit and Leo-Vince slip on with 45 pilot and it wouldn't stay consistent at idle. Now after many jet changes to see If i can figure it out I ditched the air box awhile ago (plastic was falling apart at the threads and it was a PITA to take on and off) for a UNI Pod filter which fits very well (see picture). It still has the same problem. I have tried a 42 pilot, 45 pilot, and 48 pilot. The bike rides best with 48 pilot but every time I go off-Throttle the exhaust rumbles during engine breaking not sure if this is completely normal or not. The idle will stay at 2000-2100 for a good 45 seconds or so then drop to 1100-1300 until I flick the throttle sending it back to 2000 again to repeat the cycle. No amount of messing with the idle screw or the fuel screw that I have done changes this behavior. The bike is always either at high idle or about to die. For the life of me I can't get it to stay consistent at 1500-1800. I have looked for air leaks by spraying starting fluid at the rubber intake manifold, manifold port that used to run to emissions canister (now removed), and each exhaust joint with no changes in RPM. I have gone through and cleaned the carb multiple times to the best of my knowledge. I have replaced the throttle slide vacuum plate rubber gasket. The bike runs great except at idle. I can't figure it out and am posting here hoping to find someone smarter then me, haha. Thanks for reading
Anyone got any ideas? Today I tried taking the mixture knob from almost zero turns out to 3 turns in quarter inch increments. Every time I tried to set the idle using the black idle screw it would jump from 1300 to 2000. I can't think of what could be causing this. The TPS is unplugged, I have fresh gas. My next thought is to pull the carb, completely disassemble clean and potentially try a size 50 pilot jet. Even if your just taking a guess I could use some advice.
Sorry, no experience with Husky carbs. What you are doing makes sense - strip it down and carefully reassemble and check that everything is in good condition and nothing is sticking. I would reassemble with standard jets if you have them, to get a baseline before changing anything.
Pulled the carb and checked the hotstart/choke. Both bores are clean/free of debris and have a firm spring. All the jets are new within 500 miles and look as shiny and clean as when i put them in. The vaccum plate has some spring to it which i take as an indication that the rubber seal is still good (also put a new one in 500 miles ago). The float height seemed pretty lean based on this video View: https://www.youtube.com/watch?v=oxeGEfph7WM so I adjusted it based on the videos instructions. When I get the new manifold delivered I will update and let you guys know the results.
After setting the float height correctly and replacing the intake manifold the bike runs a little better, but no change to the idle condition. This winter ill check the valves other then that I can't think of anything else that could cause this.
The throttle cable is working well and smooth. Checked with the plastic cover off. The bike idles pretty steady at 2k now after the float level change. I still can't get the idle to set at a lower rpm. Other then trying a 50 pilot or checking valves or possibly a ECU problem i'm not sure what it could be. The slide itself doesn't seem worn out or grooved.
I replaced the intake manifold and have sprayed starter fluid on each exhaust joint, the manifold, and the nipple on head side of the intake no obvious changes in rpm were observed.
Sounds like there is still some idle channel blocked in carb. fuel screw is 2 rounds open in mine,with jd jetting kit.Too little,and symptoms are like yours.High idle,or dies. Stock filter&housing.TPS connected. Idle air jet blocked it goes very rich,so not likely if it does improve with bigger jets. But worth a look anyway if carb is in hand. Both air jets are in back,remove velocity stack and they are visible. Blocked idle air,it stayed running in idle only with hot start knob pulled.
I ordered all new gaskets including mid body gaskets and I'm planning on stripping/cleaning it 100% to see if I can find anything. Maybe I'll find a broken up gasket in the mid body blocking an idle circuit passage.
Sorry for the super late update. The mid body gaskets were completely shot. Replacing them wasn’t easy, but it’s not as difficult as everyone makes it out to seem. Idle responds to mixture screw now and is set at 1600-1700.