Having Trouble Getting Maxim 550 to Idle

Hey yall,

I recently got my bike started again after it had been sitting for awhile. I cleaned the carbs (twice) and changed the plugs and that did the trick (sort of).

Now, though, the bike dies if I let it idle.

By turning the idle adjustment screw, I can get the bike to idle higher, but the throttle response becomes erratic. If I open the throttle, the engine will remain revved at 3-4k and either takes a second to return to idle or, if the screw is too far to the right, won't return to idle at all.

Otherwise the bike runs fine, I can ride it and the acceleration seems perfect. But if I take my hand off the throttle for 3 seconds, it dies.

Any help would be appreciated!

 

Did you remove the pilot screws when cleaning the carbs? What about their o ring, washer and spring?

If not I suspect your pilot circuit is not clean and you'll need to start there.

There are other possibilities.

Valves in spec?
Bench sync then vaccum sync?
Mixture adjustments?

Miles on the bike? Add it to your signature. Also your location helps incase someone is near by and you'd like a hand.

 

To this I'll add, after "bench sync" but before "vacuum sync" (in other words, while the carbs are still off the bike) FLOAT LEVELS verified using fuel and the "clear tube method."

Valves first though.

 

Thanks for the replies yall! I THOUGHT I cleaned the pilot circuit, but maybe that is my problem.

I turned my Pilot Screws 2 1/2 turns out from seated, but maybe that isn't exactly right? Could this be a pilot screw problem?

Trying to do everything I can do avoid taking the carbs off again. I realize that it's going to have to happen soon, but it'd be nice to put it off until I have a day or so.

 

2 1/2 should be good to get it started. It's not your final adjustment.

Float levels can be checked on the bike. Clear tube method with fuel. If they're wrong they've got to come off.

Do not shortcut the carbs or skip the valve steps. You'll chase your tail until you do it all right the first time.

 

Thank you so much!

Possibly stupid question: What's the procedure on setting the pilot screws? Should I do them one by one, possibly leading them to all be a little different, or should I adjust them all the same amount of turns no matter what?

 

I prefer plug chops, where you run the bike for some miles, then hit the kill switch at about 5k, now pull the plugs & read them, you are looking for a brown bag colour, lighter you are lean, darker too rich, adjust the PMScrews a fraction of a turn either way.

 

You're just gonna pretend nobody ever mentioned valve clearances, aren't you?

They won't go away and the longer you put it off the greater chance of doing long-term damage to your motor. They only get tighter, it's just a fact that won't change by ignoring it.

At 18K you are approaching (or even PAST) the "danger zone" if your valves have never been touched. Initial was to have been at 3000 miles, and then every 5000 thereafter.

Gotta do them now or you'll never get the carbs properly sync'ed. Honest.

Have you done a compression test on this motor, to see if you're wasting your time or not?

 

haha, not gonna let me get away with that, huh?

I plan on doing checking the valve clearances ASAP. No idea if they've ever been done, I got the bike with about 16000 miles on it. Since it's my first rodeo, I'm reading all I can about it beforehand...including your walkthrough.

I just did the "thumb on the sparkplug hole" compression test when I was trying to get this puppy started. I'll do it for real tomorrow morning.

Thanks again!

 

You might freak yourself out if you do the compression test first, a tight valve or two can produce falsely poor readings.

There is a reason that checking and adjusting the valve clearances is the VERY FIRST STEP in the "Maintenance" section of the factory service manual.