new battery, still won't idle

[stecz]

I apparently had multiple problems...

The battery is replaced, but it still won't idle... (it did just the other day)...

So, now I'm wondering if the diaphram in the fuel valve is bad. (I already have one on order, but it's not in yet).

Would that cause this symptom?:

The bike seems to run fine above idle. Cruising is smooth, doesn't seem down on power. But, when I let off the gas, the rpms quickly drop to 1k or so and then from there, they slowly drop until the motor dies.

I rode it on Saturday and Sunday and it never did this, so it's somethign that has changed.

If I adjust the throttle cable out a little, it raises the initial speed some, but it will still slowly drop rpm until it dies. Thoughts?

[Tarbash 27]

did you try raising the idle adjustment on the carbs?

[stecz]

no yet...

instructions?

[Hoomgar]

There is a little thumb screw knob or just a screw on your carbs (mine are VM and it is on the bottom) that is a simple idle adjustment screw. They are notorious for vibrating loose and dropping your idle.

It's part number 57 in this drawing for your carbs:

[Dink]

My wifes bike would not idle, no amount of tweaking or adjusting helped.
Replacing the Rectifier/regulator fixed it, BTW the rec/reg tested as OK.
Dink

[argonsagas]

My first thought was also the idle adjustment as in the diagram above, but you said that pulling the throttle cable to open the throttle a bit more only makes a momentary difference, and the bike still dies.

It sounds like Dink's idea may be what you need to look at, as you may be getting just enough voltage to support the system at higher RPMs, but not enough at low speed, and the battery, while new, does not get a full charge, so it cannot support the draw needed when the charging system voltage drops off at idle speed.

Follow instructions for a full check by using the "Stator Papers" located on this site "In the Garage"

[stecz]

Just ran the first part of the electrical checks...


Brand new battery.

shows 12.7 volts with the ignition off

Shows 12.7 or so at 800rpm

shows 13.8 - 14.0 at 2500 rpm

shows 14.8 or so at 5000 rpm

So the troubleshooting chart shows I'm in great shape.

The RR is warm after driving, but I can hold my hand on it for a long time without BURNING...

Another key here is that it idles great when cold (choke for 30 seconds), then without choke. When warm, it will not idle.

I also put a vacuum pump on the fuel valve and it holds a vaccuum and a vacuum is being drawn on the port.

Any other ideas?

I'm going to mess with the idle adjustment next, but the temperature related part of this seems odd.

[stecz]

ok, adjusted the idle up a little, so it didn't stall, but it's not idling consistently at 1100 rpm, so something has changed... I need to drive it a little bit more and see what's going on.

[Tarbash 27]

what do you mean by not consistently? if you mean doesnt stay perfectly at 1100 rpm. mine idles a bit rough but it runs perfrctly fine. maybe a carb sync could help it out.

[stecz]

more like the idle is at 1100 pretty good, but sometimes sits closer to 2k... that may be the throttle cable hanging up or something, but otherwise the throttle action is very smooth...

[DimitriT]

Check your spark plugs. Do they look fouled? The symptoms you describe could be due to running rich on the idle circuit.

[tconroy]

check for air leaks around carbs.did you clean carbs? Rust in the tank possibly got in carbs???etc.Plugged pilot jet passage?

[stecz]

frustrating....

The guy I bought the bike from owns a little shop and he cleaned/rebuilt the cards...

I went on a ride last night and it ran great, but this morning I was going to go ride with a buddy and it fired, but died and now wont' restart. It smells like I have fuel, I know I have spark (pulled a plug and tested).

acts like it's flooded, cranks great, but doesn't fire at all.

I tried cranking for a little bit with the throttle wide open to help clear it if it's flooded, but no joy.

Time to go look at that used Ducati Monster near by...

[gsx1311]

I had a similar problem, turned out one of the main jet needles was sticking open just enough to flood one cylinder at idle. It would be fine for about a minute after a ride, until it started loading up. Check all the plugs and see if one of them is fouled.

Good luck!

Gary

[stecz]

I must have flooded it really badly...

A couple of hours later it started, but you could tell it was really loaded up, but cleared itself out and now runs fine.

If one of the jets was sticking open, would it run poorly? Because when I'm riding, it pulls really cleanly in any gear at any rpm, I don't get any dead spots, etc.