Revs dying on full choke (Oil leak fixed? 12/06/12))

[CRM]

ah the red herring post then

ignore the plug for now. remove the tank, degrease the lower engine and jetwash - just be careful with the lower rad and dont blast it and bend fins.
once its dry and degreased should be very easy to spot where its coming from.
take pics as you go - i want to see how much oil was in the airbox lower please. a mist is one thing but a puddle means its been run with way to much in and puked it all out into the airbox.
this is where my money is at, and the vent pipe i bet if you trace it down - i bet it appears just above the oil slick

[missis sumner]

So I had another look last night.

It's definitely not the sump plug or oil filter, and I don't think it's the sump itself. The oil is dripping down and collecting around the underside of the gearbox(?) and sump bolts:



And then I started cleaning/more dismantling:


The air box was fairly clean, certainly no more oil in there than when I last looked (before I overfilled the oil).


It's definitely not the breather/drain from the air box either, as this exits way down the bike, second from the ground in the above photo.

This is the state of the front sprocket before I started cleaning around the area:


Is this push-rod supposed to slide out easliy?


There appeared to be some oil, or it could have been chain gunk around the corner of the cylinder head:


So I didn't trace it last night, but it's all clean(ish) now, so that if it reappears, it may be a bit easier to see tonight.

While I was at it, I pulled plugs 1 and 3. They were all new some 1000 odd km ago and they both had a slight bit of oil in a patch around the base?
No 1:

No 3:


I take it it's not a good idea to start it with the exhaust off? I'll need to get that back on to run it.

Wooo... and I just found this thread:
viewtopic.php?f=24&t=23527

Looks very useful.

[Neosophist]

I've seen the rocker box's leak many times, there sealed by a rubber gasket. Oil will seem out, drip down the engine and collect at the bottom.

Check around there, especially if you have the tank and carbs off.

[missis sumner]

I've seen the rocker box's leak many times, there sealed by a rubber gasket. Oil will seem out, drip down the engine and collect at the bottom.

Check around there, especially if you have the tank and carbs off.

I've left the carbs on, but the lower edge of the rocker cover over cylinder one did seem a little suspect. I'll see if anything has emerged from lower down later on, but I need to get my exhaust polished up and back on the bike before I run it.

I also need to buy some more hand wash...

Also talc and a 36mm spanner may be on my shopping list.

[missis sumner]

I still haven't put my exhaust back on so haven't run the bike since cleaning it, but last night I ran my finger along the rocker cover gasket only find a slight trace of nice fresh oil...

It was enough to convince me to whip the cover off and sure enough there was what looked like a tracked path of oil on the gasket in that lower corner over cylinder one.

So after cleaning it all up, what should I use to seal the gasket into the rocker cover groove? The Honda manual says "Honda Bond A" - I haven't a clue what this is so would something like Hylotyte Red be ok (or even plain silicone sealant)?

[missis sumner]

Just looking at my plugs again, could the same gasket be responsible for the oil on my plugs?

[Neosophist]

I still haven't put my exhaust back on so haven't run the bike since cleaning it, but last night I ran my finger along the rocker cover gasket only find a slight trace of nice fresh oil...

It was enough to convince me to whip the cover off and sure enough there was what looked like a tracked path of oil on the gasket in that lower corner over cylinder one.

So after cleaning it all up, what should I use to seal the gasket into the rocker cover groove? The Honda manual says "Honda Bond A" - I haven't a clue what this is so would something like Hylotyte Red be ok (or even plain silicone sealant)?

Honda Bond A is like a silicon gasket, you use this to glue the rocker gasket into the metal cover, not the rubber to the engine, it's only used to stop the gasket dropping out while you put it together.

I wouldn't put anything on it, if you use silicon etc, if can get into the camshafts etc and cause trouble.

You can still buy new gaskets and they are quite cheap. Clean it up and reseat it for a start.

And yes.. if its' leaking the oil could go into the spark plug recess too.

[missis sumner]

I still haven't put my exhaust back on so haven't run the bike since cleaning it, but last night I ran my finger along the rocker cover gasket only find a slight trace of nice fresh oil...

It was enough to convince me to whip the cover off and sure enough there was what looked like a tracked path of oil on the gasket in that lower corner over cylinder one.

So after cleaning it all up, what should I use to seal the gasket into the rocker cover groove? The Honda manual says "Honda Bond A" - I haven't a clue what this is so would something like Hylotyte Red be ok (or even plain silicone sealant)?

Honda Bond A is like a silicon gasket, you use this to glue the rocker gasket into the metal cover, not the rubber to the engine, it's only used to stop the gasket dropping out while you put it together.

I wouldn't put anything on it, if you use silicon etc, if can get into the camshafts etc and cause trouble.

You can still buy new gaskets and they are quite cheap. Clean it up and reseat it for a start.

And yes.. if its' leaking the oil could go into the spark plug recess too.

Ta. I did clean the gasket and wipe all around the top of the cylinder head with brake cleaner on a clean cloth last night (as per the Haynes instructions), before I put the cover back on as a temporary measure. It may be ok as it is then.

What I don't understand though, is when you replace an oil filter, you put a bit of clean engine oil on the rubber gasket to seal it, but with this rubber gasket on the rocker cover, it has to absolutely clean and dry to seal properly. Odd. Is it because you screw the filter on, so the oil is there to allow it to slip, but when you bolt something down, it's not needed . Thinking out loud, really...

Edit: Oh, and the obligatory photo:



It does look like dried up oil down the plug holes, no?

[missis sumner]

I think I've finally sorted it. It's a bit of a botch, and I really need a new gasket as it's perished a bit above the exhaust outlet, but this seems to be holding:



I ran the bike on the stand until it warmed up, then put it away on the sidestand on Sunday. There was no sign of any leakage when I checked last night.

Yeah, I know it's a mess, but it'll do until I get round to checking my valve clearances.

Oh, and I think it's still dying down on full choke - I'll have to post a video when I have a bit more time, and when I actually try to start it with the fuel tap on...