TOPIC:

The blubbering suggests too rich or a electrical problem.
Steve

swest wrote: The blubbering suggests too rich or a electrical problem.
Steve

If too rich, why even though it's already warm would I have to choke it for a minute or so to get it to stay running off choke?
If electrical, why would it run fine after it warms up?

Once warm and riding down the street it runs fine. Come to a stop it idles on it's own fine. The problem is when I turn it off for a few minutes (10-15) and then try to start it again. It doesn't want to start unless I choke it. Once started I have to let it run on choke for a minute of so before it'll idle on it's own again.
I know the engine isn't getting cold that quickly. The case and cylinders will still be warm/hot to the touch. It's gotta be something with the carbs. At cold start #2 cylinder doesn't get hot as fast as the rest of the cylinders. And I can hear one cylinder popping or misfiring through the exhaust. I wouldn't think it's an electrical misfire since I just put new Dyna coils and plug wires on it. When installing the coils I shrink wrapped the wires and eye terminals going to the coils. Just doesn't make since for it to be an electrical problem when it runs fine the entire time I'm riding it.
I almost want to say #4 cylinder is occasionally doing the same thing. I noticed at least a once it wasn't getting hot as fast as 1 and 3 were. As you know #2 and #4 are on different coils. Now unless I have an electrical problem further down the line I can't believe both new coils would be suspect in causing the problem.
I'm still thinking it's a carb issue. That being said ... off they come again to make damn sure their clean and the floats are set properly. I'll look again at the float tangs and see if the angle against the needles looks excessive and correct it accordingly. I'm considering getting new floats and needles if for no other reason peace of mind in knowing their working properly.

Robert

What kind of carbs, CV or VM? Have you checked your valve adjustments.
Steve

I just looked at your sig. Those are CV. Check your diaphragms.
Steve

When I went through the 550 carbs last week, #4 barely passed the thumb test. My ass was puckering the whole time being they are TK's and parts are hard to come by. It runs fine. I do have to use the choke to start it though just momentarily. Thy're made to run lean and that air injection system doesn't help. Try capping off the intake ports. You might have a air leak there.
Steve

Going back to your question about the carbs. Yes, they're Mikuni CV carbs.
Although I know I should have while the cam/valve cover was off, no I have not checked the valve clearances.
And yes, I did check the diaphragms. They're still relatively soft with no signs of holes or cracking.
Last time I had the carbs off I replaced the vac lines so I wouldn't think I'd have a leak there. But I'll check anyway.

Just order a whole list of parts from Z1 including new float needles. Thinking mine are OK, I decided to wait on new floats. Z1 told me they've seen times when the needle dampers get week causing them to have to be completely compressed before the needle will shut off the fuel. Hence possibly the reason why I had to bend the tangs as far as I did.

Robert

The diphgrams can look good and can be. Put your thumb over the large vent in the back after lifting the slides with your finger. Hold your thumb over the vent and see how fast or slow they fall. Slow, good, fast not so good. Air leak.
Steve

The diphgrams can look good and can be. Put your thumb over the large vent in the back after lifting the slides with your finger. Hold your thumb over the vent and see how fast or slow they fall. Slow, good, fast not so good. Air leak.
Steve

Ok, I'll check that. But wouldn't a bad diaphragm or any other air leak make it run bad all the time / not just at start up? As before, it runs fine once it gets past whatever this false since of being cold is. The only thing I know of that would do that is something still being wrong in the carbs. I just don't believe an air leak, electrical or ignition problem would just go away after it runs for a minute or so.
Although I don't think my use of the clear tube method lied to me, you have convinced me I shouldn't have had to bend the tangs as much as I did resulting in the possibility of having improperly set floats. We'll see if it changes when I install the new needles and seats. If not ... ???

Robert

Yes, they control the slides. With a already lean mixture , the slides not working right could cause it to be overly lean. When it warms up it can run better.The air injection system could have a leak as well.
Steve

swest wrote: Yes, they control the slides. With a already lean mixture , the slides not working right could cause it to be overly lean. When it warms up it can run better.The air injection system could have a leak as well.
Steve

Yes, I know the diaphragms control the slides and I understand it running better when it warms up. But what about the fact that it's already warmed up and still has to be choked to get it started? (after it sits for 5-10 minutes) If I turn it off and start it right back up again it does fine. It's the sitting after not running for XX minutes it has it's choke to start problem. Then after it's running you would think since it's already warm I could take it off choke almost immediately. No. I have to feather the choke keeping the rpms slightly elevated to keep it running till it (for the lack of better words) clears out and idles without dying. Sure, if I wanted to I could get it past the bogging and sit there revving the engine till it decides to idle but we know that isn't right either.

In an earlier posting you stated "........ knowing the use of pod filters is a far cry better than the stock air box......"

I don't know where you got that idea, but it is not factual, especially for a stock engine with CV carbs. If you put pods on it you will spend a fair amount of time and treasure trying to get them to work as well as the stock airbox with the stock air filter in place. Some folks have eventually been successful, but it is not usually a simple task, and there are often lingering performance issues such as the affect of rain and/or side wind.

Regarding the problem of needing to use the choke so much - if you have not done so already I recommend you test the carb holders for air leaks. If air is being drawn in through the carb holders it might explain your need to enrich the air/fuel mixture by using the choke. The effect of carb holder leaks can vary widely as the temperature of the cylinder head and/or carb holder changes. This is because the air leaks in between the mating surfaces through tiny cracks in the rubber, and as these cool or heat up the rubber on the carb holder mating surface may seal or not seal better against the cylinder head. In any event, this is worth checking because it is very easy to do, and if you find a leak it should be corrected.

Carb holders will eventually develop tiny cracks in the mating surfaces between the holders and the cylinder head that can cause them to leak at idle. These cracks cannot be seen with the carb holders in place. I suggest you try the following. Get the engine warmed up and temporarily set the idle as low as possible without killing the engine (lower than 900 rpm if possible). The lower the better because with the idle very low the slides are nearly shut and the vacuum inside the carb holders is at its highest. Then spray carb cleaner around the carb holders, especially where they mate with the cylinder head and where the carbs attach to them. Carb cleaner works best for this test as it doesn't leave an oily mess with WD40 or evaporate so quickly that it is not drawn into the leaks as can happen with propane or starting fluid (ether). If the engine dies or reacts to the carb cleaner, you need to replace the carb holders. Carb holder leak related problems are noticeable at idle but generally don't have much impact when riding because the throttle is open. If you find you need to replace the carb holders soak the screws with Kroil for a couple days before attempting to remove them, and use JIS standard, NOT Phillips, screwdriver bits, and this will greatly improve the odds that you will not break or strip a carb holder fastener as so many have done. Let me know if you need info on JIS bits, I have a good link for making your own at no cost. Ed