and you still have not remarked on the float height yet.

 

the jet needle (the needle attached to the vacuum piston) certainly should have a smooth, linear taper, as should the float needle..(obviously..
i'm guessing that perhaps you may want to acquire an actual mercury manometer. the slow spin-down to idle settlement is indicative of an off-sync rack, or a vacuum leak..

strange problems that plauge your machine..

 

I've ordered 2 carb kits for it due to the worn float needles, but actually got it back to normal by continuing to mess with the a/f needles. Backed them out 3.25 turns and it's as if nothing ever happened. I'm not sure what caused the change but as of now, it's running like it should. Up-and-down idling is even smoothed out.

Someone may need to explain "float height". I was under the impression that fuel level in the bowls is what determinedfloat height, but apparently I'm assuming wrong.Dragone#19?

 

Put the carb kits in last night. Finally...it runs like it should. Idle is rock-solid at 1300. I think I'll have to play with the a/f needles a bit, as 3.25 turns seems a bit much now.Overall....major improvement. I guess worn float needles cause more trouble than I thought they would.

 

glad to hear it's purrrring now![8D]

 

It's official...I own a possessed 250...and it's not possessed by anything happy. Just when I think things are all ironed out, some new side effect surfaces. Is it really possible that a carb kit made things worse?

I started having a severe lack of power yesterday afternoon while cruising around 40mph. I figured mixture screws were still in need of fine-tuning, so that's what I spent the rest of the evening doing. Just when I thought I found a sweet spot, it made it hard to start. Normally, this bike starts the second you push the button....no throttle necessary. Now I have to give it gas for it to start. Cold or hot.

Rode it to work this morning, and it did great all the way here. When I arrived, I got a refusal to idle. Adjusting the idle screw millimeter by millimeter either sends it past 2000, or under 1000, which kills it. I tried again to dink with the mixture screws, starting with 2 turns out and backing out 1/4 turn each time, arriving at 2.75 and now I get a no-start.

I think I've had about enough. The next time I get it running, the next purchase may be a for-sale sign. Next bike will be new with a warranty. And hopefully fuel injection.

 

if you are having an intermittent problem like that its porbably outside of the carbs - like a dieing fuel pump/clogging fuel filter etc..

 

No pump or filter...gravity fed.

One thing that is starting to make itself obvious is that this stuff only seems to happen when the engine is at it's hottest (temp needle at the middle of the scale, cooling fan cycling).

I let the bike cool for about 90 minutes this morning after it refused to start.Went outside and it fired right up...and IDLED. Drove it home without issue (got my car out and left the bike at home). None of this stuff seems to happen right after the bike is started at home. I let it warm up for 5-10 minutes in the mornings and it runs and idles fine when I leave. It was sure running raggedy by the time I got to work though.

Is there some adjustment on the carb that I'm missing? I've had it completely apart, cleaned the jets, air bleeders, put in a carb kit and now this. I've had the air/fuel needles backed out everywhere from 2 to 3.5 turns and everywhere in between. I'm truly at a loss.