blowing oil

[denaamisarjan]

Hi everyone,

I've been reading the topics for a couple of months now, but hadn't anything to write so far. So here's my introduction.

I'm Arjan, from Holland. I got a XS650 custom with a velorex sidecar.
I bought 1,5 year ago, rather cheap. So before driving it, I had to repair some stuff.

What I did so far:
changing the tires,
mounting a modern alternator and regulator
repairing electrical stuff (indicator, break lights etc.
changing the slides inside the carbs.
adjusting the valves

what I have to do: fix the Bendix, the starter motor won't kick in.
check the carb. alignment, since the bike is vibrating between 3000 and 4000rpm.


For now, the bike is running great. There's just this one issue, that keeps on following me:
the crankcase vent. is blowing enormous amounts of oil. everything behind the opening is covered in oil, lots of oil!
To solve this, I made a hose, leading from the vent. to the intake-filters. Didn't help, there's still lot's of oil on the bike. I think it's blown away by driving-wind, before it is sucked into the engine.

Today I drove about 150km, mostly highway. I must have lost about 0,3 liters via the ventilation.

I'm afraid, i'll have to pull the heads. But am not sure what the problem might be. Since the bike is running great en has plenty of power, i'm not sure if for example the piston-rings are worn..

what do you suggest I do?

 

[5twins]

How much oil are you putting in? Yamaha recommends only filling to about half way between the low and high marks on the dip stick. Go to the high mark and you could get excess oil coming out the breather.

 

[denaamisarjan]

I read that somewhere indeed. Normally I fill it up till just above the "low" mark. Than, the amount of oil, coming out is, much less. But still, i have to clean my battery and regulator every 100 km's..
This time, I filled it about halfway, even a bit less in fact. But indeed, more than normally.

 

[5twins]

You might want to check your dipstick. Yamaha revised the amount of oil used in these around 1975. They lowered the level about 10mm to help solve the very problem you're having. A new dipstick with lower marks was installed. Maybe someone swapped an older dipstick into yours. Here's how to check it .....

 

[MaxPete]

Huh. As I've said before - I have been around these bikes since the late 1970's and I have never been aware of a dipstick mod before. I have been overfilling my '76C (Lucille) just as I used to do on my '75B back in the day.

5Twins - you are amazing.

Thanks!

Pete

 

[grizld1]

If the dipstick is correct for your bike, check compression; bad compression rings can leak pressure into the crankcase. If compression is OK, install a one-way valve in the breather line.

 

[MaxPete]

Griz - do you have a suggestion about what type of check valve to install (perhaps a photo....?)

 

[denaamisarjan]

thanks for the tips.
I'll check all of them next week. I'll report my results!

 

[grizld1]

Pete, I use the krankvent valve from ET Performance: www.krankvent.com . Sorry, I'd have to pull the tank to get you a photo. It's a very spendy item--$95.95 US for the metric kit, which is what to use on our bikes--but it's purpose built as a crankcase breather valve. I've used it for several years, and it's very effective; oil loss from the crankcase breather just doesn't happen any more. The thing is noisy, but I don't see that as a downside; it's lots of fun to stand there acting concerned while the smart guys tell me what's causing the "engine noise" and what I'll have to do to fix it. Breather valve: $95.95. Entertainment value: priceless!

 

[denaamisarjan]

I haven't had much time last week. But I checked the dipstick. Mine is the "new" type, so that's not the problem.

Next, i'll see if I can find a place to do a compression check.

 

[fredintoon]

Hi Arjan,
that's my rig, too! And my bike also started blowing oil worse than an elderly 2-stroke running a 12 to 1 fuel mix.
I checked all manner of things, gave up on finding the cause, parked the XS650 rig and ran my XS11 rig instead.
Then my son shamed me into taking another look.
Removing the bike's gas tank let me see that the breather casting on the back of the cylinder head had a 5mm gap
all round and that only 3 of the required 4 bolts were still there.
The fix took all of 10 minutes.

 

[wrenchjohns]

if you drop the hose near to the chain, it won't go dry. john

 

[5twins]

....... yes there's only a finite supply of oil on this planet, best not waste it, lol.

 

[Michaelo]

2.5 litres of oil, simple. Drain, clean both filters, replace. Fill with oil (2.5 litres) then check in the dip stick. The level is taken from the dip stick out and sitting in the hole. Not screwed in.
Then go for a ride, see if the engine is "drinking" it. What are the plugs like?

 

[peanut]

compression leaks from the cylinders into the camchain tunnel /crankcase from a leaking head gasket is a common cause of this symptom too.
A lot of folk use liquid gasket on both sides of the head gasket, around the cam chain tunnel and stud holes to prevent or cure this problem.
I remember Anlaf of yellow banana fame rebuilt the engine 4x times before curing his issue.
Always worth retorquing the head to see if the problem is reduced or eliminated which is a good diagnostic

http://www.xs650.com/threads/help-third-top-end-rebuild-and-still-blue-grey-smoke.30829/

 

[retiredgentleman]

denaamisarjan.........................your engine needs a top end re-build, simple as that!

 

[denaamisarjan]

thanks for all the reactions!
Fredintoon, I'm hoping my problem is just as easy to solve! I've checked to breather box before, and torqued in down. But, still hoping for a solution like that.

Michaelo, i haven´t checked the plugs jet, but will post a photo soon. I'm expection black plugs. When the engine is cold, there's blue smoke from the exhaust.

peanut, that's a great tip, thanks! I'm gonna check it and post the results.

retired gentleman, i'm afraid so, but before I spend a lot of money on doing that, I first like to be sure, that this is actually the problem.

 

[retiredgentleman]

Quote:
"I bought 1,5 year ago, rather cheap."
The reason you were able to buy it so cheap, is that the previous owner knew the engine needed a top end re-build, but he didn't want to go to the work and expense of doing it, so he sold it.
How many kms are on the engine?

 

[5twins]

Blowing blue smoke out the exhaust is a pretty good indication that your motor is not healthy.

 

[peanut]