Oil spray ?

[nb1914]

Hi all,

After my bikes first ride i noticed that there was a light oil film everywhere i.e. even on the head steady brackets rear frame, barrels near the plugs where there is a large air fin etc etc. Still plenty of oil in her, i thought perhaps the oil feed to the head might be leaking but then i would have imagined an oil pool in the head but no. there doesn't seem anything obvious and i thought these engines were a very low oil pressure system. Is it possible for oil to spray out the rocker covers ?, i remember the PO had used gaskets as well as O rings on all rocker covers but i can see any leak on them. Is it possible for the oil system to become over pressurised if the sump oil filter and the other small one on the right become clogged ? also any well know issues that might cause such a wide dispersal of oil ?, engine runs fine so at a loss.

 

[MaxPete]

The rocker covers are not pressurized at all - its atmospheric in there. The gaskets or o-rings are only there to stop the odd oil drip and keep dust out.

As was said recently in the oil pressure gauge thread - the bearings in the XS650 engine are nearly all roller or ball bearings and these do not require high pressure oil as is needed by journal bearings (as found in Honda CBs and, I think, some Brit bikes). Rolling element bearings work fine with just a bit of nice, clean, relatively cool oil. The downside is that they cost more, take up more space and run noisier than journals - but I'll take those disadvantages anytime because they're tough as nails.

It turns out that Yamaha did a great job in making the XS a pretty tough ol' gal. I guess that's what sparked the legend that at the end of time after the nuclear holocaust - only three things will survive:
1) cockroaches;
2) Rolling Stone musician Keith Richards;
3) the Yamaha XS650.

Cheers,
Pete

 

[retiredgentleman]

These engines do leak a small amount of oil. Oil on the upper part of the engine is not due to either oil filter becoming clogged.
Certainly you should open up both the sump strainer and the right side strainer to inspect as that is just normal maintenance.
The only solution is to clean the engine very thoroughly. Once the engine is oil free, you will then be able to see where the oil is coming from.

Yes the rocker covers can leak a small amount of oil. Remove them and inspect. All years can use gaskets I believe and some years use O-rings. I have actually used both gaskets and O-rings at times. I now use just O-rings and find I have zero leakage, so I recommend O-rings as the best solution for the 4 covers. A member here (ggGary) used to sell them.

 

[MaxPete]

I wonder if your oil feed pipe is leaking? Check the two banjo bolts are the top fittings that take oil into the cylinder head cover.

 

[5twins]

What kind of washers did you use under the 4 outside acorn nuts on the top of the head? Those studs drain oil back down to the bottom end and require a sealing washer of some sort (brass, copper, rubber/metal).

This motor can be made relatively oil tight but it does have lots of potential leak points. Besides what's already been mentioned on top, check the points and advance housings, rocker end caps, and the top cover joint.

 

[fredintoon]

FWIW, check the engine breather vent casting. My Heritage Special had developed a 1/2-litre per 100 KM oil leaking habit that Mr. Stupid couldn't find the source of but became obvious when my son asked if the one missing bolt, the three loose ones and the 3MM gap around the breather vent casting's gasket might be a clue.

 

[nb1914]

thanks all , i will check everything mentioned, 5twins interesting you mention those 4 bolts. originally i thought the rear left one was leaking but when i saw oil on top of the head steady brackets i didn't follow it up, i suppose being thinner i,e semi synthetic 10/40 a leak or leaks could be sprayed with the air rush. I think the 4 bolts have a thick copper washer as per the below picture. Can these be removed and re-torqued without removing any other head bolts as they are the outermost bolts

 

[fredintoon]

thanks all , i will check everything mentioned, 5twins interesting you mention those 4 bolts. originally i thought the rear left one was leaking but when i saw oil on top of the head steady brackets i didn't follow it up, i suppose being thinner i,e semi synthetic 10/40 a leak or leaks could be sprayed with the air rush. I think the 4 bolts have a thick copper washer as per the below picture. Can these be removed and re-torqued without removing any other head bolts as they are the outermost bolts

View attachment 90760

Hi nb1949,
well, you may well "get away with it" like that but a better way would be to slacken off every head fastener in reverse tightening order, check those sealing washers, replace them if they need it then re-torque the head like the book sez.

 

[5twins]

That washer doesn't look like copper to me, it looks like steel. If it is, that could very well be your problem. And yes, synthetic oil is much more prone to leaking out of an old bike than regular oil, probably another one of the many reasons I don't use it. Yes, you can pull the nuts off one at a time and replace the washers.

 

[nb1914]

thanks again all, i have picked up some SAE 40 mineral oil ( rock oil classic ) which i will change after hopefully tracking the leak or leaks down, yes those washers under the 4 bolts do look like steel. do the nuts screw down ok onto a standard thickness copper washer i.e. the thickness of the current steel washers has been done to allow the nut to torque up without running out of thread

 

[retiredgentleman]

I use copper washers that are 0.071" thick. If you buy some that are at least that thick you will have no problems at all.
If you want to have a quiet top end, its best to use 20W50 in these engines.
30 ft/lbs torque is recommended.

 

[5twins]

MikesXS sells 4mm thick brass washers for this purpose. They work OK but are getting very (too) expensive. Before that, many of us used the 2mm thick copper washers from Suzukis, part #09168-10017. That's what I put on mine .....

http://www.partzilla.com/parts/detail/suzuki/SP-09168-10017.html

The Suzuki copper washer tip and the increased torque value tip come from here .....

http://www.650motorcycles.com/CopperWashers.html

If you don't mind waiting a couple weeks for delivery, you can use these .....

http://www.ebay.com/itm/10-Pcs-Copp...49f2811&pid=100005&rk=2&rkt=6&sd=231479115961

 

[nb1914]

i had another close look at those 4 nuts and washers, I'm not sure what the originals were like but i did see what looked like a plastic coating on one washer peeling off. could the washers be the original where the oil seal part has perished or even possibly the PO re-torqued and knackered them.

 

[5twins]

The originals were thick black rubber bonded to a thin metal washer. The metal washer was at the top so even if the rubber had peeled off it, you would still see black rubber all around the sides. Honestly, yours don't look at all like that. They look all steel, which is the wrong thing to use in this spot.

 

[nb1914]

looks like i will need to be brave and pull them off a put copper whalers on. Would it be best to completely remove and re-torque one at a time or gradually loosen all 4 in a diagonal sequence then re-torque in a diagonal sequence. Any chance that instead of the nut coming off the stud might undue

 

[5twins]

I would do one at a time. Bring it back up to about 25 pounds and move on to the next one. When all 4 have been done like that, go back around and bring them all up to 30. I do it this way all the time without problems. Most of the ones I work on locally have never had the head bolts and nuts touched since they were new. Yes, many, if not most, have leaky head gaskets because of this. When doing one of these, I do all the head nuts and bolts, not just those 4 outside acorns. Even if I find some of the nuts or bolts tight, they still come off so I can apply anti-seize to their threads.

 

[nb1914]

thanks i will have a go at it

 

[nb1914]

final check, i have managed to get 8 x 10mm id 22mm od 1mm thick copper washers (solid), not sure if i should use a single washer or 2 per nut to keep thickness something like original.

Is there a chance of the entire stud coming undone ?? if the nuts are seized slightly

 

[5twins]

It's not very common for the studs to come loose. I've never had it happen. If your new washers are only 1mm thick, I'd double them up. Then I'd place an eBay order and put the thicker ones on when they finally arrived.

 

[gggGary]

pretty much impossible to remove studs from case without heating them first, they are installed with locktite from the factory. Yep found out the hard way, wasn't pretty.
May slot the studs on an engine I build one of these days, install the studs without locktite, per the Yamaha racing guide, top jobs can be done without pulling the motor.