Burning Oil Smell on right side of Exhaust header

[MysterYus]

Hi everyone. I just got myself an ST1300 with 99k miles.

Been looking through the forum for a while and I observed that there are some pictures of leaks in other threads that I could relate my symptoms to.

I started noticing this leakage when I started smelling oil being burnt. Upon checking, I see the following:


There are traces of oil on the right exhaust header as well:


Smoke is observed when I run the engine from the exhaust that are covered with the oil AND THAT IS WHAT produces the smell.

I did clean the drips to see if there is any leakage but to my surprise, there are no drips after wiping them off.

So I did ride it around for awhile and when I checked again, the leak is observed.

I'm unsure which component is failing but from what I read, and with the possibility that the leak reaches the exhaust header, I assume that it is coming from above and that would potentially be the output shaft seal (I could see some oil on the rubber ("clover").

Would be glad to hear some input from the seniors!

Thanks

 

[ibike2havefun]

Welcome to the forums.

My first guess would be that the rubber mat behind the header was pinched slightly, the last time the header cover was removed and reinstalled. This is a very common (and easily-made) mistake, as I demonstrated to myself a couple years ago. It is also easily corrected, though a bit tedious as is everything else that requires removal of the cowling.

• Remove the cowls
• Thoroughly clean off any traces of oil on the outside of the engine, under the oil pan, etc.
• Loosen the header covers- you may want to remove them entirely so you can refresh the gasket sealer in the "half moons" at the front
• Make darn sure the rubber mats behind the covers are completely free and clear
• Re-seat and re-tighten the header covers, continuing to ensure you have not re-pinched the rubber mats in the process of reinstallation
• Start and run the engine, giving it time to warm up fully
• Examine the engine looking for evidence of further oil leakage
• Give it the "sniff test"
• When everything passes muster, reinstall the cowls

Go ride!

 

[MysterYus]

Hi!

Thanks for your input As im preety new to the bike’s parts name, could I clarify if the header cover you are referring is this:

Article [13] - ST1300 - Maintenance Lid Removal | ST1300 Articles

Here are some pics: If you have the Fairing Deflectors it looks like this, left arrow to the access panel and right arrow to the Maintenance Lid: Take a small object like a screwdriver and push the center of the push-pin in and you'll feel it 'pop'. Then, pull the push-pin out If you...

www.st-owners.com

Pertaining to the rubber pinch, may i know which rubber mat are you referring to?

 

[rogo]

He is referring to the cylinder head cover AKA valve cover. The rubber mat is over the engine between both covers. There are threads in here somewhere.

 

[ibike2havefun]

@rogo has it correct. The "maintenance lid" is part of the exterior cowl; what I'm talking about is the thing underneath that cover:

2004 Honda ST1300 A CYLINDER HEAD COVER | Service Honda

(never mind that I linked to the 2004 diagram- this component of the ST1300 engine has not changed over the production time, AFAIK.)

The rubber heat mats are behind the cylinder heads, and can be a little hard to see. (That's why they are so easily pinched.)

This is the cylinder head cover (in this image the front of the bike is to the left) and the "half moon" tabs in the gasket are visible at the lower left area just tot he right of the "F-24" label:



I tried to find the mats in the online parts diagrams but came up empty. In hunting for a photo, I found the thread I started on this very same issue, back in 2018. My photos look very much like yours.

 

[NobodySpecial]

My guess would be the output shaft seal. I had an on and off drip / burn-y smell and it took me over a year to figure it out. The seal itself is not particularly difficult to r&r but the flexible boot on the front of the swing arm can be a real pain. I'll see if I can find some pictures if you think you want to take a look.

 

[SMSW]

A few more points. You did not say what year bike you have. Most of them are at least 10 years old, some pushing double that. Look carefully at the valve cover gasket. These last a good long time on 1300's, but a few guys have replaced theirs.
* Don't forget to seal the half moons as @ibike2havefun said, these are semi circular cut outs at the front of the valve cover.
* The valve cover bolts are long, and seal by means of a flat rubber washer. These do compress with age, you might consider replacing them.
* Those valve cover bolts - #18 in the picture in post #5 - are long and are somewhat difficult to thread correctly since you are aiming for a hole on an angled cylinder head. Be very careful not to cross thread them. Some guys have done so. Do NOT over torque them, they seat on that collar just above the threads. Tightening them too much to seal the rubber washers will strip the threads.
* The Honda Service Manual is the most useful accessory you can buy for this bike.

I don't want to overwhelm you, but you might find this Article useful:

Article - Maintenance Items Needed for a New (old) Bike | Articles

This article is the result of collaboration by Andrew Shadow, CYYJ, jfheath, Max Pete, SMSW, and SupraSabre. Igofar’s list was copied from the first link listed above. Click on the attached file. This one is V.11; in the future, any changes will be noted in the title on the first page as the...

www.st-owners.com

 

[BakerBoy]

+1 to a number of opportunities discussed for oil leaks.

It is also possible for the valve head cover gasket itself to not have been positioned correctly or to be damaged. If so, oil can leak into any spark plug well. You can pull the spark plug connector caps and look down in each spark plug well to see if there's oil film/drips in there. Honda added a weep hole to each spark plug well to allow any fluid accumulating around the spark plug to drain out the side of the block (dripping onto the exhaust header).

 

[MysterYus]

@rogo has it correct. The "maintenance lid" is part of the exterior cowl; what I'm talking about is the thing underneath that cover:

2004 Honda ST1300 A CYLINDER HEAD COVER | Service Honda

(never mind that I linked to the 2004 diagram- this component of the ST1300 engine has not changed over the production time, AFAIK.)

The rubber heat mats are behind the cylinder heads, and can be a little hard to see. (That's why they are so easily pinched.)

This is the cylinder head cover (in this image the front of the bike is to the left) and the "half moon" tabs in the gasket are visible at the lower left area just tot he right of the "F-24" label:



I tried to find the mats in the online parts diagrams but came up empty. In hunting for a photo, I found the thread I started on this very same issue, back in 2018. My photos look very much like yours.

Thanks for this. Still trying to find time to get it checked.

My guess would be the output shaft seal. I had an on and off drip / burn-y smell and it took me over a year to figure it out. The seal itself is not particularly difficult to r&r but the flexible boot on the front of the swing arm can be a real pain. I'll see if I can find some pictures if you think you want to take a look.

I have that feeling too! Based on where the oil landed, its definitely from up tops Will attempt to check for trails to find the source.

A few more points. You did not say what year bike you have. Most of them are at least 10 years old, some pushing double that. Look carefully at the valve cover gasket. These last a good long time on 1300's, but a few guys have replaced theirs.
* Don't forget to seal the half moons as @ibike2havefun said, these are semi circular cut outs at the front of the valve cover.
* The valve cover bolts are long, and seal by means of a flat rubber washer. These do compress with age, you might consider replacing them.
* Those valve cover bolts - #18 in the picture in post #5 - are long and are somewhat difficult to thread correctly since you are aiming for a hole on an angled cylinder head. Be very careful not to cross thread them. Some guys have done so. Do NOT over torque them, they seat on that collar just above the threads. Tightening them too much to seal the rubber washers will strip the threads.
* The Honda Service Manual is the most useful accessory you can buy for this bike.

I don't want to overwhelm you, but you might find this Article useful:

Article - Maintenance Items Needed for a New (old) Bike | Articles

This article is the result of collaboration by Andrew Shadow, CYYJ, jfheath, Max Pete, SMSW, and SupraSabre. Igofar’s list was copied from the first link listed above. Click on the attached file. This one is V.11; in the future, any changes will be noted in the title on the first page as the...

www.st-owners.com

Based on the previous owner, it is a 2007. Hence, the bike is definitely more than 10 years. I'm planning to change all the gasket. Not sure how much this will cost. Hopefully, it will not be expensive. Thanks for the sharing of the link

+1 to a number of opportunities discussed for oil leaks.

It is also possible for the valve head cover gasket itself to not have been positioned correctly or to be damaged. If so, oil can leak into any spark plug well. You can pull the spark plug connector caps and look down in each spark plug well to see if there's oil film/drips in there. Honda added a weep hole to each spark plug well to allow any fluid accumulating around the spark plug to drain out the side of the block (dripping onto the exhaust header).

This is what I am worried about. Better to get this checked before riding it more.

Hopefully the fixes are within repair and not as costly. Most importantly, I HOPE that the bike will be running as great with minimal problems after the repairs. High mileage scares me but ST1300 is just such beauty to not get one

Thanks for the share of knowledge. Greatly appreciate it Will try to get this checked and update here on my findings.

 

[SMSW]

Most importantly, I HOPE that the bike will be running as great with minimal problems after the repairs. High mileage scares me but ST1300 is just such beauty to not get one

These bikes run well with few problems if regularly maintained. And high mileage for an ST is north of 200,000 miles. Your bike is just shy of middle age. Most of our problems with these bikes are due to lack of maintenance.

 

[MysterYus]

Its been awhile and here's an update.

As I am not mechanically inclined as I expected myself to be, I decided to drop my bike off at a trusted workshop of mine.

After thorough check, it was due to gasket/seal issues.

My mech mentioned that the main leak was actually from the output shaft seal. NobodySpecial, you're spot on with this one.

However, when the mech did further checks after fixing the leakage on the output shaft seal, there are leakage (minor) at the head cam cover. As ST1300 is not a mainstream bike here, he followed ibike2havefun tips in ensuring that the rubber did not get "caught/pinched" during reinstallation. The gasket/seals have been replaced too and problem solved for this one. Thanks

In summary, it was all due to wear and tear. The bike being 14 years old, I understand that such problem may arise.

All in all, no more leakage, and am a happy owner of this beautiful ST1300

Thanks again everyone for sharing your knowledge of the bike. Highly appreciate it!

Ride safe everyone!