URGENT HELP REQUIRED

[Bob1150GS]

Just back from holiday and this morning wheeled out the GS started first time after standing on the centre stand for 2 1/2 Weeks whilst fastening my helmet the OIL SIGHT GLASS blew out of its housing. I immediatley stopped the bike phoned Clarks BMW who informed me that it is only a push fit so pushed it back in a fired it up again no problem gradually added oil back up to full and all seems fine. So on a bike which was put into a garage and not touched for 2 1/2 weeks what could possibly cause the back pressure? Has it happened to anyone else? Has anyone modified the seal or housing? If so how? I will be off for a ride later but for the first 15 or so mins will only be 200 yards from the front door. If further problems will post again when back.

 

[Greg Masters]

Bob

I think that this is a rare, but not unknown, problem.

I would be inclined by buy a brand new sight glass and seal, remove the old sight glass again, meticulously clean the location with a rag soaked in cellulose thinners (or something similar which will remove the oil but not leave a film deposit) and very carefully fit the new window.

Greg

 

[Deadskin]

Sight glass popping out

As Greg says it's pretty rare,
but you could make one of these

 

[cdw]

Urgent Help Required

Suggest de-greasing with IPAlchohol available from Maplins as cellulose thinners will attack the lacquer on the sump casting.

Scary what happened to you, imagine the result if you were going round a left-hand bend at speed. From reading these threads, GS's are getting worryingly prone to mechanical failures, disasters even.

Regards

Chris

 

[Deleted Member Mtn]

what's a sight glass?

 

[Deadskin]

what's a sight glass?

It's the ickle round window on the side of your bikes engine

 

[Dahoum]

From reading these threads, GS's are getting worryingly prone to mechanical failures, disasters even.

Which threads are these?

 

[cdw]

Urgent Help Required

Other worrying threads include loose lower triple clamp bolts and brake failure due to easily damaged ABS wiring.

There are enough nutters on the roads already without having to be bothered with potentially dangerous mechanical failures IMO.

Regards

Chris

 

[Mr K]

Other worrying threads include loose lower triple clamp bolts and brake failure due to easily damaged ABS wiring.

There are enough nutters on the roads already without having to be bothered with potentially dangerous mechanical failures IMO.

Regards

Chris

Thought it was the 1200 that had the above maladies?

 

[Pukmeister]

what could possibly cause the back pressure

On most engines, the pressure in the crankcase is caused by the rings passing, which could be the most likely cause if your piston rings have settled and the oil seal around the rings has drained away over 2 1/2 weeks of standing. I suspect that after a few revs, the oil pressure would build up and the bores/rings would be lubed and sealed tight by the oil film.

As for the excessive pressure, not sure about the particulars of an 1150 (mines a 1200) but most engines are designed with a crankcase breather circuit to vent excess pressure into the induction system where any oil vapour can be breathed and burnt off.

Like has already been mentioned, if the original sightglass should be an interference fit, I doubt it will be effective anymore. Buy a replacement, thoroughly degrease the housing and fit a new one. Be sure to investigate the crankcase breather/vent circuit on your bike (eg blocked) to prevent a reoccurrence of the sightglass incident.

 

[Ste@SSB]

I have only heard of one other 1100/1150 doing this in the last 18 months or so ... and that was due to some serious overheating ... poor guy had started his bike in the garage then forgot about it and gone to the shops ... it blew the sight glass out but enough oil stayed in the sump for it to run till the heat melted the battery terminals ... we replaced the brake pipes, battery, sight glass and ran some flush through ... all it needed was the tappets doing and the job was a good 'un...

Never ever heard of one coming out with the bike moving ... though it could I suppose if the crank case breather was blocked...

Quite sure that if you refit the old one it will blow out again...

 

[jeff garnett]

Hi
was the circlip in the hole No 1 in photo

 

[Bob1150GS]

Update

The old sight glass has held for 250 miles up to the revlimiter at times. I am still concerned. How do I locate and check the crank case breather? Also in the back of my mind is there a pressure releif valve in the oil filter? Looking forward to the replies.

 

[Steptoe]

Also in the back of my mind is there a pressure releif valve in the oil filter? .

There is a relief valve in good quality filters (mine have them ) - But not in the cheapo cheapo budget filters

 

[Bob1150GS]

Releif valve

Would the genuine BMW part contain a valve?

 

[Bob1150GS]

Reply to Jeff Garnett

Jeff is that a genuine picture? It looks it to me. Because Clarks BMW insisted that the sight glass was not retained by anything and was just an interference fit in the housing this I did query as being an engineer of many years in a past life would not be normal. The standard practice would be a retaining ring of some sort. Anyone else got an opinion on this?

 

[Steptoe]

I've never come across any retaining rings holding the sight glass in place.

They often leak. And i just replace them with a new one.

I've heard of them popping out ( i've never had it happen to me) - usually when the engines revved while cold.

The bikes it's happened to, have just replaced the sightglass and never had another problem -

Just replace yours and i shouldn't think you'd have anymore worries -

 

[Polarbear]

me thinks jeffs photo is of a 1200 engine not an 1150.

 

[(RIP) Bin Ridin]

I read that to remove them, you drill a hole, screw in a selftapper and give it a good pull.

 

[jeff garnett]

me thinks jeffs photo is of a 1200 engine not an 1150.

Yes it is a 1200 sorry

I have a 1200, Thought we all had a 1200 sorry Bob1200GS

jeff