stalls when hot

[1_v8_merc]

Im having a similar problem on my 650. But seems to come and go.
Got a new battery, hope this isolates the problem down.
(old battery wouldn't hold much of a charge, so I couldn't perform a stator test or any other tests with accurate results.)

[mike_of_bbg]

Well you said the plug was black, so it sounds like it might well be getting some fuel. If you open up the throttle does it kick in?

[Flyboy]

Jasper, just a thought here, you say the number 1 plug is wet, yet you say it is not getting fuel, contridiction in terms there, just becase the plug fires outside of the cylinder, does not mean it fires in the cylinder, it may be breaking down under combustion pressure, mixture etc, I have seen it on more than one occasion, swap it out with a plug from another cylinder to varify it. It won't be the first time a brand new plug out the box is dud.
Does the number 1 header get hot, or even warm, its tempreture in relation to the others will tell you a story.
Your float does sound a bit low, as I recall, it should be around 2-3mm from the mating surface, I am sure someone will correct me if I am wrong.
If the plug checks out ok, it seems the carb will have to come off.

[Gonzo]

Check your plug gap too while your checking Flyboy's recommendation.

[jasper]

Yes well...I wish I could tell if it is kicking in at higher revs. My feeling is no, but it's hard to tell.

And it ain't the plug unfortunately.

I swapped the #1 plug for the #2 plug to test whether the plug was the problem already. No change. I checked the gaps on the plugs when I installed them and they were fine at 0.030"

I agree though flyboy - black and wet sure doesn't sound like a lack of fuel to me either, but I have lots of spark and even when I switched the coils and wires #1 wasn't firing.

Way way to rich could cause this too of course. I'm not very certain about my fuel level measurement. I haven't devised a good way to attach a hose to the drain. Maybe my fuel levels are actually way high or maybe a needle valve isn't closing.

It's worth noting that when I first got the bike it sounded like it was missing and it stalled when it got hot. I rebuilt the carbs and installed thinner shims and replaced the ignition system...and it's still missing and stalls when it gets hot.

[BigD_83]

Yes well...I wish I could tell if it is kicking in at higher revs. My feeling is no, but it's hard to tell.

And it ain't the plug unfortunately.

I swapped the #1 plug for the #2 plug to test whether the plug was the problem already. No change. I checked the gaps on the plugs when I installed them and they were fine at 0.030"

I agree though flyboy - black and wet sure doesn't sound like a lack of fuel to me either, but I have lots of spark and even when I switched the coils and wires #1 wasn't firing.

Way way to rich could cause this too of course. I'm not very certain about my fuel level measurement. I haven't devised a good way to attach a hose to the drain. Maybe my fuel levels are actually way high or maybe a needle valve isn't closing.

It's worth noting that when I first got the bike it sounded like it was missing and it stalled when it got hot. I rebuilt the carbs and installed thinner shims and replaced the ignition system...and it's still missing and stalls when it gets hot.

Jasper...PM me. I have a real fuel height gauge that might work better for you, one that screws into the drain hole.

[Flyboy]

Ok, like I said in my first post, it seems like you have a rich cut thing going on there, so, yes, too much fuel can cause it as well.
What I suggest you do, pull the carbs and whip off the float bowls and set up the floats in the normal wayby measuring from the top or step of the float to the gasket surface, 24 - 26 mm or something like that, I don't know thw actual numbers for your bike, check in the manual to be sure.
This will get you right in the ball park, until you can rig up a clear tube setup to use.
While the carbs are off, may as well go through them with a fine tooth comb again, it just takes a little bit of dirt in one little channel to cause your headaches.
You won't be the first person to have cleaned the carbs, only to find something in there a second time round.
Let us know what you find.

[mike_of_bbg]

Well, if there's no combustion the pipe should stay pretty darned cool at idle. Off idle you should feel the exhaust pipe warm up. I'm thinking that #1 is too closed; it's drawing fuel in but no air (or not enough). It doesn't take much to be off; the throttles are barely cracked at idle. You need to vacuum sync your carbs...

[jasper]

Jasper...PM me. I have a real fuel height gauge that might work better for you, one that screws into the drain hole.

Hi Derrick. I sent a couple of PM but they don't appear to be getting logged. (Weird)

I am stoked on borrowing the fuel gauge and on doing a carb synch. You can call me at 604 809 0930 or email me at rexjoropo@gmail.com and we can talk about timing and logistics.

Super thanks for the offer to help. I'm oh so close to getting my issues sorted.

thx

[cowboyup3371]

Do you have your PM settings to save sent items? Go in to the User CP and change that setting.

[jasper]

Do you have your PM settings to save sent items? Go in to the User CP and change that setting.

Done...I turned on my email notification too. I believe these were defaulted in the other forums I hang out on.

Cheerss

[jasper]

Update...

BigD Derrick (not actually very big if I'm honest) was very kind enough to lend me a fuel level gauge and the results were surprising to say the least.

#1 and #2 couldn't have been more spot on, and #3 and #4 were a smidge high...but not enough to worry about.

So good news, bad news.

So I took the Mike's excellent advice and verified that #1 was firing on the throttle...by feeling the exhaust pipe. Cold at idle - warm then hot on the throttle.

and then I took Mikes's excellent advice again and cracked open the #1 butterfly until I heard the exhaust note change and felt the exhaust pipe start to get hot at idle.

That's a BINGO as Hans Landa would say.

So then I leaned out some mix screws, I note #1 can still be turned in all the way without stumbling...so it's probably a bit worn.

Long story short...I ghetto synched it and it's running better than ever.

Derrick is being kind enough to lend me his brand new never been used synch tool too, so maybe this weekend I can dial it in just right.

This is great guys - great forum.

[mike_of_bbg]

Aww, shucks...

The symptoms were altogether too familiar, if you know what I mean (mine was #4)

"Ghetto sync" - that's a new one

[jasper]

UPDATE:

Rode the bike to work today. It runs great....for about 35 minutes of my 37 minute commute.

Same...old...thing.

It stalls when it gets hot in even a little bit of traffic.

On the way home it was really bad (more traffic) and the roughness would persist through the middle range as well.

Funny thing is, after 20 minutes of moderate to hard riding, it idles great at stop lights or whatever. Same thing after 25 minutes, and after 30 minutes. Any longer than that though and it gets boggy and won't idle and usually won't start until I let it cool down.

Then it runs great again.

I'm still attributing it to richness, and a carb synch and mix screw adjustment planned for later this week should go a long way to making this better, but I have a nagging feeling this issue may never actually *go away* for real.

Will post back - loving the bike when it runs though.

[BigD_83]

It sounds like the heat could be causing expansion somewhere, and that cooling down let's it relax to normal. The fact that it starts up and idles again after cooling reinforces that idea. That is suitably vague, but maybe someone else can pick up that line of thought.

That being said, I haven't the foggiest idea of where that would most likely be happening, but possibly the head/valves. You've already changed the coils. Have you managed to check the voltages once things get hot and the bike starts to stumble/before it dies? Could this be an overheating RR situation?