Running Rough IN Wisconsin

[motoguy]

Looking for some advice here. Got my S10 out from storage now that the salt is mostly washed off the roads and gave it a good go through, bearings, bakes, bolts, spokes etc. The bike ran good last fall when it was put away but not so much now.
So here's the low down, engine started and runs good at cold start, then starts to drop one cyl. and back fire out the exhaust. Just a blip of the throttle and it clears up for a bit then the same thing. Took the bike for a short spin thinking that it might clear up when good and warm. Wishful thinking, at low speed(1,2,3rd gear) eng. will back fire if the throttle is held steady. Accel or decel is fine(no backfiring). Going down the road 55-60 eng will surg up and down(no backfiring that I can hear).
Here is what I had done as of now. Suspecting bad gas I removed the tank and drained the gas and put in fresh premium non ethenal gas with sea foam. Also checked the air filter for any restriction. Air filter is good and no mouse nest to be found. Looked over any vacuum lines for cracks and leaks wiring also. Put back together and run. Got the same results. Checked batteries voltage( 13.9 at idle) and batt. is in good shape. I now suspect something electrical or possible fuel inj./ press.
Any advice would be greatly appreciated.

 

[autoteach]

First things that come to mind is:
tight valve/s that are decreasing compression at low throttle position enough to misfire
fuel injector that is partially clogged
TPS related issue
TB sync.


Diagnose the easy things first.

 

[Derekj]

Looking for some advice here. Got my S10 out from storage now that the salt is mostly washed off the roads and gave it a good go through, bearings, bakes, bolts, spokes etc. The bike ran good last fall when it was put away but not so much now.
So here's the low down, engine started and runs good at cold start, then starts to drop one cyl. and back fire out the exhaust. Just a blip of the throttle and it clears up for a bit then the same thing. Took the bike for a short spin thinking that it might clear up when good and warm. Wishful thinking, at low speed(1,2,3rd gear) eng. will back fire if the throttle is held steady. Accel or decel is fine(no backfiring). Going down the road 55-60 eng will surg up and down(no backfiring that I can hear).
Here is what I had done as of now. Suspecting bad gas I removed the tank and drained the gas and put in fresh premium non ethenal gas with sea foam. Also checked the air filter for any restriction. Air filter is good and no mouse nest to be found. Looked over any vacuum lines for cracks and leaks wiring also. Put back together and run. Got the same results. Checked batteries voltage( 13.9 at idle) and batt. is in good shape. I now suspect something electrical or possible fuel inj./ press.
Any advice would be greatly appreciated.
[/quote

I would suggest, inserting a wire in the clutch plug as this will eliminate the restrictive circuitry, just to make sure that it's not the problem.Or make sure you test ride again in 4th and 5th. Somehow, it sounds like a blocked /bad injector. Could there have been rats or mice camping out near your bike during storage?

 

[MrVvrroomm]

check your airbox

 

[chwhnd]

I do believe he said he checked the air box, I believe that the other posters are correct in the fact that it might be the fuel injectors, the fact that it was running fine when you put it up for storage tells me that it was a sitting issue, I would go there first.

 

[Doug C]

I had similar but not exactly the same poor running last fall after a long trip. For me ultimately turned out to be a small amount of water in the fuel filter.Picked up a tank of bad fuel somewhere along the route. I removed the fuel pump from the tank soaked the filter in solvent and back flushed a small amount of water and a fair amount of sediment from the filter. It solved my poor running issues. I did happen to find an eBay brand new pump and filter assembly and have been running it through the winter. They seem to be no longer listed. Only available from Yamaha and fairly expensive. The pump/filter assembly is fairly easy to remove to inspect or clean. Helps if the tank is nearly empty. There is one little plastic clip that needs to be persuaded out of the way. Good luck with your searching.

 

[bigbob]

Not necessarily this problem, but would not a tank of ethanol clear the water out of the filter?

 

[Checkswrecks]

A lot of gasoline will stick up the fuel injectors over surprisingly short time. Try running a tankful with Yamaha Ringfree, Chevron Techron, or Seafoam at MAX dosage. I use the Seafoam and know it is 2 oz/gallon, the others may be more or less.

 

[Bigbore4]

Double check under the right side covers, seat etc. for mice. Fekking little bastiges are awful, not to mention relentless.

 

[motoguy]

No critters to be found(just gremlins). The one thing I did not do was remove the fuel pump and check. But I did remove the tank to get all of the fuel out and put in fresh gas.
What is puzzling is the fact that it runs fine under load or acceleration. If there would be a restriction in the fuel(plugged filter or screen) or clogged injector I believe this would not be.
Still looking over the wiring for anything suspicious. I don't believe that anyone has had any ECU failures or wiring issues that would cause this. I spoke with the serv. manager from the dealership and he seems to remember something similar on a FJR at his previous employment, and that he would check and see. Other than that he said that they would need to see the bike and plug it in. Almost to that point now.

 

[Checkswrecks]

No critters to be found(just gremlins). The one thing I did not do was remove the fuel pump and check. But I did remove the tank to get all of the fuel out and put in fresh gas.
What is puzzling is the fact that it runs fine under load or acceleration. If there would be a restriction in the fuel(plugged filter or screen) or clogged injector I believe this would not be.
Still looking over the wiring for anything suspicious. I don't believe that anyone has had any ECU failures or wiring issues that would cause this. I spoke with the serv. manager from the dealership and he seems to remember something similar on a FJR at his previous employment, and that he would check and see. Other than that he said that they would need to see the bike and plug it in. Almost to that point now.

You are thinking backwards on this and gave the clues in your first post. It's not that the injectors are being restricted, it is that one is leaking at idle and possibly slightly sticking (hence surging). Backfiring out the exhaust (actually after fire), as you described is typically when the mixture is too rich so it burns in the exhaust. When too-lean, the mixture burns much faster and you can get a "back fire" in the intake.


When the injectors are off-idle and flowing more fuel, this idle leakage is no longer a factor.


My strong suspicion is that if you don't want to go the SeaFoam route (it is largely naphtha, which is a solvent), or if it doesn't work, you will ultimately need to either have the injectors ultrasonically cleaned or replaced.

 

[motoguy]

checkwrecks, I must agree with you. My first guess would have been a injector but was hoping for something more simple I guess. As for the seafoam, I did give it a try with no success. I'm a firm believer in the stuff, when I prep the bike for storage I run the tank as empty as possible, add the seafoam then fill the tank with fresh premium non ethanol gas and drive it to get the mix in everything. This has worked well for many years with motorcycles and snowmobiles etc. guess I'll have to bite the bullet and take it in.
Thanks for the advice

 

[WRW9751]

Checkwrecks:
There are a number of YouTube videos on injector cleaning. Haven't done it on the Tenere but have tried it on KTM. Seems to work fine!

 

[autoteach]

Where are you at in Wisco?

 

[motoguy]

Where are you at in Wisco?

Dorchester..Almost dead center.

 

[motoguy]

Took the bike in to the dealer today . This is going to drive me nuts until I hear from them. A year out of warranty too. I think its gonna hurt the wallet as well.

 

[motoguy]

Well, if anyone is interested. I spoke with the dealer and they cant find what's wrong with my bike. The serv. writer said that he called Yamaha and they have never heard of anything like this. Yamaha had them adjust the throttle bodies to a new fuel setting/ adjustment and to replace the spark plugs. I personally don't think this will do anything, but we'll see. So far they are 7 hours into this and nearing $700. I'll be calling tomorrow.

 

[autoteach]

You brought it there to be fixed, not for them to spend money not fixing it. If you ok'd the work, you are stuck, but you should hold them to fixing the bike with their diagnosis, not chucking shit at it. If they say it needs a battery, the battery should damn well fix it. If it is spark plugs, that should fix it. The problem is that none of these twats no up from down when it comes to proper FI diagnosis so figuring this out will be only by chance and not likely by any type of skill. If you picked the bike up today, and it isn't fixed, why should you pay? If you want it diagnosed and fixed, find a shop that knows their ass from a hole in the ground. This may involve a drive. I apologize for lighting off like this, but I am so tired of this crap from dealers and shops, and customers should know that they only have to pay for repairs. They haven't repaired anything.

 

[Dogdaze]

You brought it there to be fixed, not for them to spend money not fixing it. If you ok'd the work, you are stuck, but you should hold them to fixing the bike with their diagnosis, not chucking shit at it. If they say it needs a battery, the battery should damn well fix it. If it is spark plugs, that should fix it. The problem is that none of these twats no up from down when it comes to proper FI diagnosis so figuring this out will be only by chance and not likely by any type of skill. If you picked the bike up today, and it isn't fixed, why should you pay? If you want it diagnosed and fixed, find a shop that knows their ass from a hole in the ground. This may involve a drive. I apologize for lighting off like this, but I am so tired of this crap from dealers and shops, and customers should know that they only have to pay for repairs. They haven't repaired anything.

::026:: Yep! Kind of the way I feel, I can change out plugs, fuel, airfilter, etc etc, until I solve the issue, trial and error, but I pay someone else to know from the get go, not trial and error at my expense.

 

[Koinz]

First things that come to mind is:
tight valve/s that are decreasing compression at low throttle position enough to misfire
fuel injector that is partially clogged
TPS related issue
TB sync.


Diagnose the easy things first.

I vote for tight valves or sticky valves/buckets.