not running

[TearlessTom]

Okay here is the story;

 

Bike has been in the shop for several weeks 38 days to be exact, getting Ma Yamaha to finally fix the over heating issue which as we thought here back in January/Febuary that it was a bad head gasket.

 

Okay they finally get it all back together and the service manager calls me to tell me it is not running good.

 

Says running great on side stand, 1st and 2nd gear runs out fine but 3rd and up it acts as if it is starving for fuel.

 

They are checking the vacuum lines, I told them to check the filter for clogs, and to check for contaminated fuel as it is the 10% ethanol that has been sitting in the tank.

 

I researched here and that seems to be the normal advice,

 

(I had a similar issue on my 03 VTX which was a fuel pump bike also and Turned out it was a clogged fuel filter. Would run fine the for no apparent reason it would shut down. It only did this if the bike was low on fuel.

 

I first changed it over to a gravity feed system but that did not help, changed out the filter and that fixed it. I had put a new filter on and apparently it did not flow as well as the oem.)

 

 

So can anyone here think of any other reasons that this may be occurring?

 

I had recently sync'd the carbs, and was in the process of fine tuning the pilot's as I had put new pipes on the bike and it was running lean. but I don't think any of that would cause it to shut down like it is doing.

 

Thanks

[Thom]

check the fuel pump , it will run on gravity until it needs more gas , like in higher gears or a load

[TearlessTom]

I told then to check that and he said the fuel pump seems to be working fine. Also states the filter is clear.

 

I went up and rode it. Like he said it revs fine sitting still but under load like 3rd gear or hard throttle it spits and sputters. Similar to when you hit the rev limiter.

 

I told them I was adjusting the pilots when the head gasket finally blew and started shooting water out my tail pipe so I shut it down and loaded it on the trailer and took it straight to them.

 

So I am thinking that one or more of the pilot screws are closed or near closed as it is notible running leaner than it was before I took it in.

 

Told them to close all pilots and reset them to specs I am betting that will fix it but havent heard back from them yet.

 

Gonna give em another 30-45 minutes before I call or go back up there.

[dingy]

http://i1007.photobucket.com/albums/af193/gdingy101/youruserprofile.jpg

[Freebird]

Very good Gary. You should post it as a new thread also so that perhaps more people will see it. Thanks for taking the time to do that.

[V7Goose]

I told then to check that and he said the fuel pump seems to be working fine. Also states the filter is clear.

 

I went up and rode it. Like he said it revs fine sitting still but under load like 3rd gear or hard throttle it spits and sputters. Similar to when you hit the rev limiter.

 

I told them I was adjusting the pilots when the head gasket finally blew and started shooting water out my tail pipe so I shut it down and loaded it on the trailer and took it straight to them.

 

So I am thinking that one or more of the pilot screws are closed or near closed as it is notible running leaner than it was before I took it in.

 

Told them to close all pilots and reset them to specs I am betting that will fix it but havent heard back from them yet.

 

Gonna give em another 30-45 minutes before I call or go back up there.

Not the pilot jets or screws - if that is all that was going on, the engine would run better and stronger the more you opened the throttle. Fairly easy to check the overall fuel supply to the carbs (tank screen, filter,pump). All you need to do is take the bike out where you can quickly get it up through the gears, then pull over and shut it off. Now turn the key on and wait for the fuel pump to stop clicking, indicating the carbs are full. In actuality, the carbs should already be full and you should not hear any click at all, so you may want to shut off the fuel supply about 1/2 a mile or so before you pull over, that way you will be able to verify that the fuel pump is actually working when you turn the key on for this test.

 

OK, back to the test. Pull the bike over and shut it off with the key. Now turn the fuel back on, then turn the key on and wait for the clicking to stop. Cycle the key off and on again to make sure the clicking is all done and the carb bowls are full. The bike will go several miles on just the gas in the carbs, so if the problem is with the fuel supply instead of the carbs themselves, you should be able to start the bike and quickly run up through the gears without any problem at all at first, but two miles or so down the road when the carbs begin to dry up the faltering should start again.

 

But if this test shows the faltering starts immediately, then the problem is inside the carbs.

Goose

[TearlessTom]

Good point Goose I didn't think of that. When I went by to check on it the service manager started the bike and brought it to me so I didn't hear the fuel pump but I will check that if they haven't figured it out.

 

I don't think the pump is the problem.

 

As you mentioned it should run a ways with just the fuel in the carb bowls.

 

This is sputtering as soon as you hit a higher gear in just 100 feet of so. Like I said is feels the same as when you hit the rev limiter but not actually hitting it.

 

I seems lean as it is back firing more than it was before.

 

The reason I was thinking pilot was because I was turning them all the way in to count the turns so I could be sure to adjust them all the same when I backed them out an extra 1/4 turn for the free flowing pipes. So if they were turned in too far wouldn't that cause a too lean condition that could act like this?

 

Here is another thought.

 

I am still not that familiar with how the bike is set up as to the # of coils. My Valk has 3 so I am guessing this may have 2 or is it 1?

 

Anyhow, if it does have 2 is there a way that the bike's ICM could see the RPM's as double what it is actually turning and in so doing actually activating the rev limiter?

[V7Goose]

Good point Goose I didn't think of that. When I went by to check on it the service manager started the bike and brought it to me so I didn't hear the fuel pump but I will check that if they haven't figured it out.

 

I don't think the pump is the problem.

 

As you mentioned it should run a ways with just the fuel in the carb bowls.

 

This is sputtering as soon as you hit a higher gear in just 100 feet of so. Like I said is feels the same as when you hit the rev limiter but not actually hitting it.

 

I seems lean as it is back firing more than it was before.

 

The reason I was thinking pilot was because I was turning them all the way in to count the turns so I could be sure to adjust them all the same when I backed them out an extra 1/4 turn for the free flowing pipes. So if they were turned in too far wouldn't that cause a too lean condition that could act like this?

 

Here is another thought.

 

I am still not that familiar with how the bike is set up as to the # of coils. My Valk has 3 so I am guessing this may have 2 or is it 1?

 

Anyhow, if it does have 2 is there a way that the bike's ICM could see the RPM's as double what it is actually turning and in so doing actually activating the rev limiter?

I do not suspect the fuel pump at all, but since they had everything torn apart and seem a bit questionable in their competency, I suspect they have put something together wrong or damaged something. It would have been quite easy for them to kink the fuel hose, or maybe they just forgot to connect the TPS plug. The main reason I stressed hearing the fuel pump click when you turn the key on is to KNOW the carb bowls are full before you start the test.

 

Your bike has four coils. There is no way I know of that it could be fooling itself into thinking it was running faster that reality. Not to say that there couldn't be a problem with the ignition module or coils, just that it is not likely under these circumstances.

 

As I said in my first post, nothing about the primary circuit could cause your symptoms. I understand where you are coming from, and there is a certain (faulty) logic to your thoughts, but it just ain't so. I have worked on several bikes where the primary jets were 100% clogged, and the owners could only get them patrially running by keeping the choke on and the idle screw turned way up, but they ran pretty darned good when they got out on the road and had the throttle way open.

 

If you are worried about the mixture screws being messed up, just set them all at 4 turns out and forget about it until you get the rest sorted out.

Goose

[TearlessTom]

If you are worried about the mixture screws being messed up, just set them all at 4 turns out and forget about it until you get the rest sorted out.

Goose

 

That is what I told them to do but although they are nice guys I do have to question their compentency. Needless to say when I called back yesterday after they told me they were putting it back on the lift next they still havent touched it again.

 

I guess they are waiting on Ma Yamaha to tell them what to do or for it to fix itself or waiting on the warranty to run out in 2013.

[GaryZ]

Your symptom reminds me of a CB350 Honda I once had . . . It would start, idle, and run up to about 4,000rpm. Then, it would fall on its face. Finally found the problem to be ripped diaphragms in the CV carbs.

[TearlessTom]

Your symptom reminds me of a CB350 Honda I once had . . . It would start, idle, and run up to about 4,000rpm. Then, it would fall on its face. Finally found the problem to be ripped diaphragms in the CV carbs.

Anothr good thought, I will pass that along to the dealer. The had the carbs off so it is possible. Don't know why of if they would need to tear into them though.

 

It was running fine when it went to the for the head gasket repair.