Greetings, all. '76 R90/6, build date 01/75. Uses oil have rebuilt the top end (rings, valves, guides, etc) and it still uses oil. Referencing various posts in Airmail recently, there is supposed to be a drain port from the crankcase breather. I have the breather out again and am unable to find where the port is supposed to be, so I can verify it is clean. Has anybody got a photo or drawing of where I can find said port? All I can find is what appears to be a rough casting in the area. I would really like to be able to ride this bike and not have to carry a lot of oil.
Randy
ABC 8200
Welcome Aboard !
The subject breather and collection well lie under 2 thumb-sized covers on the RH side, under the electric starter. You can gain easy access by removing the top engine cover. The breather rubber hoses are generally no longer available, so be very careful when working with the rubber parts.
You could have one of 2 issues...
• The early style breakers used a phenolic disc (similar to circuit board material) that eventually gets chipped and eaten up. The disc needs replacing when it no longer makes a good seal (which was usually about 15 years ago !), but the better repair is to install the later model all-metal flapper valve that never has any issues. The parts fiche will probably guide you to that decision if you look up the replacement parts.
• The well is located under the second breather cover. There's a small depression (or "well") in the top of the engine that collects liquid oil droplets. In the bottom of that cistern is a small hole to allow the oil back into the engine.
If your breather is indeed blowing oil, then your air filter stands a good chance of being oil soaked. So you might check that as well.
Hope this helps.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Therein is my problem. At the right rear of the block is the vent valve(called non-return valve on the fiche). I have a new hose that goes from the valve cover to the right side airbox clamshell. I don't see anywhere in the well below the valve any holes, just a lot of rough casting residue, as in bumps. If I understand correctly, there is supposed to be a small drainback hole visible that I could use a wire to verify its cleanliness. So far I haven't found the hole. I have sprayed carb cleaner and brake cleaner in the well and it appears to go somewhere faster than just evaporating, so I presume it is finding its way back to the sump. I have tried probing with thin stiff wire at likely indications of pits or maybe holes to no avail. Maybe it doesn't exist on my engine. Or maybe I could drill one of my own?
I feel your pain, Had the same experience searching for that tiny drain hole, It's there!
Check Snowbum's site under the link below. There's a good photo of said port and a whole oil system schematic.
Thanks for the info. After perusing 'bum's site, it appears that my engine probably doesn't have the drain port in the breather cavity, based on its date of manufacture. So I think I'll have to look for another cause for the usage.
Yes I was thinking that also but you never know exactly when updates and changes were made on these old airheads.
Reference your oil usage I slowed mine down drastically by taking Oak's recommendation and switching to Golden Spectro 20/50 SYN. Believe it can take the heat our engines produce.
Good point there, 15087.
Exactly what engine oil are you running, 8200 ??
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
I have used Amsoil 20W50 and am presently using Castrol Actevo 20W50. The bike only has 125K on it.
Actevo is API SL rated, meaning it is not the best protection for your older design engine. I don't think that's the cause of your issue, but thought you'd like to know. You should be using something with the older rating of SF, SG, or possibly SH.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Castrol 4T 20/50 would be a better choice in a Castrol oil. It is a motorcycle specific oil and has the level of ZDDP your lifters demand. I use it because I can get it down the street at the FLAPS. I also run a touch of moly (Lubrimoly oil additive) in the oil. The moly is a plating lube and one must remember it was used if doing a tear down. It makes a mess and you think horrors have happened inside. Nope.
Reflecting on your query: The oil drain location on the later blocks is towards the front of the stilling chamber that runs along the right upper side of the block. It is indicated on the oiling diagram. But at 125k you can expect to be using some oil past the worn rings and valves. At 150k plan on spending some serious cash on a top end job, or sourcing a lower mileage engine.
I seldom check my oil. I have a mechanical oil pressure gauge on the dash. As long as I have good pressure I am good to run. I don't care overmuch for the crankcase level. On a very long trip I might take a peek every 1500 miles or so.
On my old leaky /5 with the original shallow pan the oil light would flash under heavy braking if the oil was low. This was caused by the oil sloshing in the unbaffled pan. I just always carried a bottle of oil and replaced lost oil as needed.
Advertisement
