Sluggish performance - oil on spark plugs?

[imranh101]

Hey all,

 

been getting really, REALLY bad performance and had to put choke on about halfway to get the bike from my apartment to my new house without it dying in neutral.

 

I figured something was up with the ignition because it felt like I was missing two cylinders.

 

Pulled spark plugs and sure enough it looks like I've got oil on the threads on the two plugs for the cylinders closest to the front tire of the bike - the back two look okay albeit a bit carbon fouled.

 

Can I get a point in the right direction on where to go from here? Where is the oil most likely to be coming from and how would I go about repairing

 

See image - left plug is one of the back two plugs, right is one of the front plugs - you can see how much oil is in the threads on it

 

Thanks as always!

[MiCarl]

Oil on the threads isn't the running problem. Your valve cover gasket is leaking and oil is pooling around the plugs. Oil gets on the threads as you remove them.

 

Needing choke to run is a symptom of a fuel system issue. Check for vacuum leaks. Put in a good dose of carburetor cleaner (Sea-foam, gumout etc.). Ride it like you stole it, that might clear up the issue.

[Patch]

Not sure you will see this but I can add a bit...

 

MiCarl is correct the gaskets are leaking.

The rear plug show signs of light recent carbon only the redish is fuel type for the most part.

The business end of both look fresh enough.

The front ones tho show cold so is where I would start!

First check voltage at the coils, looking for close to battery volts, 12ish.

Then check for spark you - can gap test or, if you have an old timing light use it on the front ones...

Note: the spark testing method @Marcarl suggests is part of his therapy and NOT supported my the membership!

If the spark test taste good then check carbs

[Marcarl]

So Marcarl now suggests to warm the engine, remove air cleaner and inner tower, and then spray a bit of cleaner into each intake. If the front 2 respond with better running, then I would look for a fuel issue. Just for kicks, squirt a bit into each of the rears and see what response you get from that exercise.

[Patch]

So Marcarl now suggests to warm the engine, remove air cleaner and inner tower, and then spray a bit of cleaner into each intake. If the front 2 respond with better running, then I would look for a fuel issue. Just for kicks, squirt a bit into each of the rears and see what response you get from that exercise.

 

Eh WOW Carl, Marca is really getting good at troubleshooting!

 

[cptriker1]

Hey all...yeah...been a LONG time since I've said something but got something that's come up need advice related to this.

So, took the bike last weekend to Hattiesburg and JUST as I got to my destination I started having exhaust noise that decreases (but still there at speed) so I'm thinking exhaust gasket on one of the front pipes.  No, hadn't isolated yet as been busy.  BUT, another issue then has appeared.  The bike started as I got closer to home to run 'rough'.  I've been noticing some 'off-idle' hesitation.  No, it hasn't been synched since it was repaired 2 years ago. No, the plugs haven't been changed since repaired 2 years ago and I know I've been WELL over 5K miles for sure.  I remembered reading about plugs (using NGK's) have to be changed often as this engine is hard on them?  Need to know what gap distance is if you wouldn't mind. 

Also, you guys might remember my post about the rectifier about me changing a year ago as voltage was low.  When I did the change I started getting the high #'s and all looked fine.  Now, I'm back to dealing with this again.  I've rechecked all lines to my new fuse panel and all appears right.  It's just that I'm not liking the variation I'm seeing.  If stopped it can drop below 12 (brake lights on) and of course goes up but not showing as high.  Simply put - I'm not seeing the NORMAL 14+ when riding (might be a little lower on the dash gauge) but runs fine.  IS THIS NORMAL is the best question?  I _highly_ doubt that anything is wrong with the stator OR the rectifier.

Sorry for mass of questions.  Last one - if I do have to synch ((and I do NOT want to do this...)) is it ultra-difficult?  I do have a tool for doing this, never used it.  I use Lucas fuel conditioner ALWAYS, but you guys think I should run a fuel cleaner?

As always, hope everyone is doing fine.  Yet another stupid storm might be heading towards MS...this shit is getting old...

[Patch]

41 minutes ago, cptriker1 said:

Hey all...yeah...been a LONG time since I've said something but got something that's come up need advice related to this.

So, took the bike last weekend to Hattiesburg and JUST as I got to my destination I started having exhaust noise that decreases (but still there at speed) so I'm thinking exhaust gasket on one of the front pipes.  No, hadn't isolated yet as been busy.  BUT, another issue then has appeared.  The bike started as I got closer to home to run 'rough'.  I've been noticing some 'off-idle' hesitation.  No, it hasn't been synched since it was repaired 2 years ago. No, the plugs haven't been changed since repaired 2 years ago and I know I've been WELL over 5K miles for sure.  I remembered reading about plugs (using NGK's) have to be changed often as this engine is hard on them?  Need to know what gap distance is if you wouldn't mind. 

Also, you guys might remember my post about the rectifier about me changing a year ago as voltage was low.  When I did the change I started getting the high #'s and all looked fine.  Now, I'm back to dealing with this again.  I've rechecked all lines to my new fuse panel and all appears right.  It's just that I'm not liking the variation I'm seeing.  If stopped it can drop below 12 (brake lights on) and of course goes up but not showing as high.  Simply put - I'm not seeing the NORMAL 14+ when riding (might be a little lower on the dash gauge) but runs fine.  IS THIS NORMAL is the best question?  I _highly_ doubt that anything is wrong with the stator OR the rectifier.

Sorry for mass of questions.  Last one - if I do have to synch ((and I do NOT want to do this...)) is it ultra-difficult?  I do have a tool for doing this, never used it.  I use Lucas fuel conditioner ALWAYS, but you guys think I should run a fuel cleaner?

As always, hope everyone is doing fine.  Yet another stupid storm might be heading towards MS...this shit is getting old...

Regarding idle: sometimes the collector baffles rust loose, they actually designed for continues flow which basically means they cause a flow draw from the cycles of each timing stroke.

However if a loose baffle should block a feed pie then this will change the chamber metrics causing a stumble.

If your rectifier or stator are defective then that too can cause the issues of rough idle or stalling

[cptriker1]

Update (11/18/20)---

Oh wow was I ___wrong__ about what the problem was!  So finally today I was able to change the plugs.  Ones that was pulled looked to be in excellent shape.  Started the bike, getting same sound (like exhaust gasket).  So, I get on the ground, engine is cold and I'm able to put my hand FULLY on the front left pipe!  Ok, this is WEIRD.  I touched the other front pipe and it had all kind of instructions to NOT do that stupid shit again!!!  :) So you start thinking that cold exhaust pipe is no ignition.  Yet, I can't find any blowing air or a key indicator that shows where in the hell is this sound coming from.  But then...I seen something FALL FROM MY CARB STACK!!!  It's the freaking choke plunger (see pic)!!!

Now I'm bewildered to say the least!  I grabbed one of the just pulled plugs and check for fire...yep...sparking like crazy.  So, that rules out loss on ignition side.  

Now I need to know if any of you guys knows what SIZE (measurement) of the missing 3 screws?  Looked down in the engine v, their gone so replacement.  I seen that on a carb teardown that locktite should have been used and appears that it wasn't by my mechanic.  If someone knows exactly what the size of these screws are I can then find and start seeing __IF__ I can get this mounted back.  I sure hope I can without having to remove anything.  Also, I didn't see a gasket so does it require one from this to the carb housing?  If so, got a part number?

I was going around my shop thanking the Lord that at the exact moment this fell and I seen it!  

As always, thanks for any help.

[cptriker1]

Update (11/18/20)---

Oh wow was I ___wrong__ about what the problem was!  So finally today I was able to change the plugs.  Ones that was pulled looked to be in excellent shape.  Started the bike, getting same sound (like exhaust gasket).  So, I get on the ground, engine is cold and I'm able to put my hand FULLY on the front left pipe!  Ok, this is WEIRD.  I touched the other front pipe and it had all kind of instructions to NOT do that stupid shit again!!!  :) So you start thinking that cold exhaust pipe is no ignition.  Yet, I can't find any blowing air or a key indicator that shows where in the hell is this sound coming from.  But then...I seen something FALL FROM MY CARB STACK!!!  It's the freaking choke plunger (see pic)!!!

Now I'm bewildered to say the least!  I grabbed one of the just pulled plugs and check for fire...yep...sparking like crazy.  So, that rules out loss on ignition side.  

Now I need to know if any of you guys knows what SIZE (measurement) of the missing 3 screws?  Looked down in the engine v, their gone so replacement.  I seen that on a carb teardown that locktite should have been used and appears that it wasn't by my mechanic.  If someone knows exactly what the size of these screws are I can then find and start seeing __IF__ I can get this mounted back.  I sure hope I can without having to remove anything.  Also, I didn't see a gasket so does it require one from this to the carb housing?  If so, got a part number?

I was going around my shop thanking the Lord that at the exact moment this fell and I seen it!  

As always, thanks for any help.

BTW....

http://www.venturers.org/Tech_Library/?action=article&cat_id=001010&id=366

Reference Figure #14 for example of screws that are missing from this article...

[cptriker1]

Update (11/18/20)---

Oh wow was I ___wrong__ about what the problem was!  So finally today I was able to change the plugs.  Ones that was pulled looked to be in excellent shape.  Started the bike, getting same sound (like exhaust gasket).  So, I get on the ground, engine is cold and I'm able to put my hand FULLY on the front left pipe!  Ok, this is WEIRD.  I touched the other front pipe and it had all kind of instructions to NOT do that stupid shit again!!!  :) So you start thinking that cold exhaust pipe is no ignition.  Yet, I can't find any blowing air or a key indicator that shows where in the hell is this sound coming from.  But then...I seen something FALL FROM MY CARB STACK!!!  It's the freaking choke plunger (see pic)!!!

Now I'm bewildered to say the least!  I grabbed one of the just pulled plugs and check for fire...yep...sparking like crazy.  So, that rules out loss on ignition side.  

Now I need to know if any of you guys knows what SIZE (measurement) of the missing 3 screws?  Looked down in the engine v, their gone so replacement.  I seen that on a carb teardown that locktite should have been used and appears that it wasn't by my mechanic.  If someone knows exactly what the size of these screws are I can then find and start seeing __IF__ I can get this mounted back.  I sure hope I can without having to remove anything.  Also, I didn't see a gasket so does it require one from this to the carb housing?  If so, got a part number?

I was going around my shop thanking the Lord that at the exact moment this fell and I seen it!  

As always, thanks for any help.

BTW....

http://www.venturers.org/Tech_Library/?action=article&cat_id=001010&id=366

Reference Figure #14 for example of screws that are missing from this article...

[Prairiehammer]

The screws are 4mm diameter, 12mm long.
Yes, there is a gasket for the choke assembly. Part number 3JB-14536-00-00
https://www.partzilla.com/product/yamaha/3JB-14536-00-00?ref=0b935775ba783008fc3eb8976f85607427091d8a

[cptriker1]

Got it!!!  This is a huge help guys!  I looked on the bike and the gasket was gone.  Found the parts on ebay so should have them next week.

Thanks so very much for those #'s!  I'll update once I got them installed and if this is fixed.  

Happy Thanksgiving!!!

[RDawson]

As to your question about carb synch, very easy. There’s a good write up in the read only section. I change plugs every spring and do a carb synch while I’m at it. I usually throw the manometer on it mid year to double check it.