Idle circuit, I guess?

When I took the carbs off the second time and made a fairly serious effort to get them clean so it would run well rather than just running (which was the big question initially when I bought it), it would light off instantly when you set the choke and thumbed the starter...and settle into a perfect 950 rpm idle when you shut the choke (ok, enrichener, choke is faster to type)...very happy with it.

But after I was out of town a couple of weeks, when I got back to it, it no longer does this...in fact won't start at all cold, choke or no, needs a shot of ether to get going. Once it has that, it's fine, runs from there...but idle stability is not good either...it will idle, but slowly drop off and die if you don't give it a little blip every 10 seconds or so.

Seems pretty clear it ate something in the idle circuits that it couldn't digest.

Ideas where to start looking? I'll just clean the hell out of 'em as completely as I can while they're off, but I'd like to have that AHA! moment where I see the problem, as opposed to just clearing it as part of the process and not noticing...

 

Sounds like they were clean but got some trash in the starter and idle circuits. How clean is the tank and are you using a inline fuel filter? That fine rust will plug carbs quickly.

 

I'm having the EXSACT SAME PROBLEM this started after I ran some carb cleaner through the tank... I think I got some rust or gookenpucky loose in the carbs and got something all clogged up... Any help on this would be appreciated...

 

You will need to take the tank and carbs off ane clean them both and install a inline fuel filter.

 

That and after you get them clean again, if you use ethanol mixed gas, run a treatment in it, or just find a local station that sells pure gasoline

 

St. Louis. Humid in summer I think. Ethanol gasoline. Tank not full so you get some condensation. Can muck up the carbs pretty quick.

 

Ok sounds good Im taking the bike in for a valve clearance job with new pads and shims and a carb sync with merc sticks...this guy says he used to race these bikes against kz 750s in the late 80s...

Can someone tell me what jet to get for individual pod filters? I'd appreciate no bs comments on PODS thanks guys...

 

I cleaned the tank prior to this, wasn't going to go through the carbs only to run fuel out of a scaly mess of a tank.

Petcock screen was intact and clear and I did put an inline filter on.

I'm wondering if maybe something I didn't get quite clean in the carbs finally got soluble and made its way to the next chokepoint. Ah well.

I've got nothing better to do

 

I have seen it happed before. Fuel filters that don't filter well. The compressed bronze filters don't catch the fine dirt that can clog pilot jets. The paper filter in the plactic or metal cans are better but not 100%. If you have that fine rust/dirt in your tank it needs to come out. My method is a can of 1000 BBs and some kerosene and shake till your arms are sore, repeat several times then drain the gunk liquid out. Add more kerosene and continue until it is clean. Follow that with a solvent rinse.

 

I used a gallon of vinegar and 6 ft of twisted wire dog chain and some nuts and bolts. Was surprised how well the vinegar ate rust and scale. It's clean in there now.

Yeah the filter is one of those you mentioned, bronze stone type, actually made for lawn implements I think.

I bet a filter for a fuel injected auto motor would work good...they have to trap stuff small enough to block the tiny holes in injectors...would look funny, as they are large, but better than eating crud. I don't know if they would pass unpressurized fuel too well though...