2015 ~5k Oil Weep

[OpusNectar]

I picked up a 2015 with 5k on the clock a month ago, and am now tackling the oil weep that it's had since I got it. The drip collects on the left side of the bike, right where the left hand rear stay for the belly pan is. Its about 3 drops after every ride on the tarmac.

No oil is coming down the head thankfully, so in thinking its the LH engine cover or the counter shaft sprocket seal. One is easy, one is not so easy.

Anyone have any helpful feedback as to common leak spots for the 390 I should look at first?

Honestly the weep is so minor I may just put a fluid retentive belly pan on and call it a day..

 

[Formula390]

If the engine is overfilled with oil then the shiftshaft seal can leak. It's actually easy to replace and you just pull the old one out and push the new one in. You can use a dental pick to snag the old one to pry it out. No need to split the case to get it out like on some other bikes. When filling the oil, it has to be on a level surface, NOT on a rear stand, and the engine must be up to operating temp. If it's filled to the fill line while still cold, it's overfull, and is the common issue which can cause a leak on the shift shaft seal. If I were to guess, I'd say this is the more likely source of a leak.

Another possible leak location is if the sprocket cover bolts are not tight, you can get a weep (or full blown leak) from there as well as there is a through hole into the transmission area of the case which is normally plugged when the bolts are in and tight.

If you need a race belly tho, I've got plenty in stock.

 

[OpusNectar]

Thanks for the reply! That is all very helpful information, I very much appreciate it. IIRC the oil level is a bit high last I checked, past the upper level in the sight glass. I am planning on doing an oil change this weekend so I'll ensure the level is set correctly then. Fingers crossed its something so simple.

Funny enough, I already did order a Tyga race belly pan from you when I discovered the weep on Saturday. Its the one heading to San Diego Looking forward to receiving it. Love my Tyga Oval system I got from you.

 

[Formula390]

Wow! So yeah that's REALLY over full. Any leaking is likely going to be from the oil being so overfull. It may resolve itself, but my guess is that your shift shaft seal is toast. Luckily, it's cheap at something around $1.25 for a replacement. I'm pretty sure that it's part number is 90130003004. I've seen that one fail and start to leak twice from overfilling on locals bikes alone. So, if your motor is THAT overfilled, then that's my bet as to where your oil leak/weeping is coming from.

The output (countershaft) seal is about $3 I believe, with part number 90230077000. From memory, it's only retained by a circlip, so I THINK that one can be pulled as well without having to split the cases. My guess tho is that is' going to be the shift shaft seal. PacMan or Chad should be able to say for sure one way or the other on if the countershaft seal can be swapped just as easily. I haven't had to replace that one yet on the test mule, or any of the locals bikes I've wrenched on.

Your belly (as well as the other orders that came in over the weekend) will all be going out later today or tomorrow morning... Technically I'm closed Mondays, and I use Sunday and Monday to get "Other Stuff" in life done on those days. I'm getting a slow start for the day today tho. I had to take the boom and stick off the back of my Backhoe this weekend. I've got some new parts inbound to do some repairs, and am also rebuilding all of the hydraulic cylinders... My problem is even with some help from one of my buddies, I'm still moving REALLY slowly (and painfully) today. Using equipment to do all the lifting and dragging helps a lot, but driving those old and slightly corroded pins out was way harder than I had anticipated! Problem is, once you start, it's almost harder to say "ABORT! Let's do this some other time when it's not so balls hot and humid!!!"

 

[OpusNectar]

Oh man, this whole time I had the shift shaft seal and counter shaft sprocket seal mixed up. Looking at the weeping, it looks to be coming from higher up than the shift shaft. In any case, i ordered both parts to be safe. Wince I am running no belly pan, im sure the oil gets pushed around by the wind, so it could surely be the shift shaft.

I believe you can also finagle the countershaft seal out with tools.

 

[Formula390]

Oh man, this whole time I had the shift shaft seal and counter shaft sprocket seal mixed up. Looking at the weeping, it looks to be coming from higher up than the shift shaft. In any case, i ordered both parts to be safe. Wince I am running no belly pan, im sure the oil gets pushed around by the wind, so it could surely be the shift shaft.

I believe you can also finagle the countershaft seal out with tools.

If it's higher up, then that could be one of the bolts which has a through hole into the transmission area of the case. Those bolts are what holds the front sprocket cover. If they are loose, you can indeed get oil seeping out from there. Some have tried taking their bike out for "a quick test ride" after changing their chain and/or sprockets... forget to put the cover on (or think "I'll just put it back on once I finish the test ride") and drench their left boot with engine oil. Ooops! So, yeah... higher up from those two points would then point to those bolts.

...and yeah, the seals can be a bit fussy about their names. LOL
Countershaft == output from the transmission / what the front sprocket is attached to
Shiftshaft == input to the transmission gear selector drum, so it goes gear shift lever -> shift link rod -> shift shaft arm -> shift shaft (sung to the tune of ""Dem Bones")

 

[Formula390]

...and, if you get tired of replacing seals on the RC... you are more than invited to come out and lend a hand rebuilding the hydraulic cylinders on my backhoe. I don't pay much, but you'll go home full to your eyeballs on Texas BBQ Brisket. I consider it a personal failure if anyone visits and DOESN'T leave at LEAST 10# heavier from the fabulous food in the area. LOL Everyone is invited out to the ranch during MotoGP weekend each April.

 

[OpusNectar]

I definitely warmed up the bike with the sprocket cover off the first time...whoops.

But, leak was there when i bough it, so I'm guessing a seal still. Will report back! Time to get some cheap dental picks.

 

[Formula390]

I definitely warmed up the bike with the sprocket cover off the first time...whoops.

But, leak was there when i bough it, so I'm guessing a seal still. Will report back! Time to get some cheap dental picks.

It's not something all that uncommon, so don't stress it. It's why I mentioned it...

Also, let me make a recommendation on the dental picks! What you want to search for are Root Elevators for oral surgery! You'll REALLY be glad you did. They have large handles and you can REALLY lean on 'em!

https://www.ebay.com/sch/i.html?_nkw=dental+root+elevator



when you are trying to pry out an old stuck seal, or wrangle with a stubborn c-clip and the like, you want something you can hold onto really well... not some dainty little spindly thing used to poke gingerly at something. "Get OUT of there you ***** ***** *********** **** ** ******!!!" I love mine!!! Buy once, use for your lifetime!

 

[OpusNectar]

Jesus, my teeth cringed once I read the words Root Elevator. Thanks for the rec, I can see these being way better than the dental picks I was about to steal from the GFs toiletry bag.

 

[Karfanatik]

If it's higher up, then that could be one of the bolts which has a through hole into the transmission area of the case. Those bolts are what holds the front sprocket cover. If they are loose, you can indeed get oil seeping out from there. Some have tried taking their bike out for "a quick test ride" after changing their chain and/or sprockets... forget to put the cover on (or think "I'll just put it back on once I finish the test ride") and drench their left boot with engine oil. Ooops! So, yeah... higher up from those two points would then point to those bolts.

...and yeah, the seals can be a bit fussy about their names. LOL
Countershaft == output from the transmission / what the front sprocket is attached to
Shiftshaft == input to the transmission gear selector drum, so it goes gear shift lever -> shift link rod -> shift shaft arm -> shift shaft (sung to the tune of ""Dem Bones")

I did this the other day. Didn't put the front sprocket cover on and noticed a good drip after the bike warmed up. Luckily caught before a ride.