Yellow marks on engine

[mamac]

Hi, I'm new on that forum and I registrated because I've just receive my new R1200GSA wich has about 1000 miles. I find today while I was washing my bike a yellow mark on the engine, the cylendar (I don't know if it's the right word in english). It's just like if something has heated. Is it normal or does color of cylenders changes when heating?
Best regards.

Marc

 

[R1150GuS]

No, they shouldn't change colour, this kind of yellow stains usually appear when fuel contacts the hot surface of the cylinders.

Check for a leaking fuel line, or maybe you accidentally spilled some gas on it while refuelling

Cheers

 

[mamac]

No, they shouldn't change colour, this kind of yellow stains usually appear when fuel contacts the hot surface of the cylinders.

Check for a leaking fuel line, or maybe you accidentally spilled some gas on it while refuelling

Cheers

Thanks a lot but is it possible to take them off someway?

 

[mamac]

No, they shouldn't change colour, this kind of yellow stains usually appear when fuel contacts the hot surface of the cylinders.

Check for a leaking fuel line, or maybe you accidentally spilled some gas on it while refuelling

Cheers

Thanks a lot but is it possible to take them someway?

 

[alimey4u2]

Several solvents will remove fuel staining but these are quite aggressive....
Toluolene, Methyl Ethyl Ketone or Acetone but these should be handled very carefully with zero contact to skin & limited contact to painted surfaces......

 

[PhilBolton]

By "cylendar" do you mean "cylinder" -

Or do you mean "exhaust pipe"???

May be a stupid question, but maybe not!!

Phil

 

[mamac]

By "cylendar" do you mean "cylinder" -

Or do you mean "exhaust pipe"???

May be a stupid question, but maybe not!!

Phil

Excuse my bad english... I mean Cylinder indeed.

 

[mamac]

Several solvents will remove fuel staining but these are quite aggressive....
Toluolene, Methyl Ethyl Ketone or Acetone but these should be handled very carefully with zero contact to skin & limited contact to painted surfaces......

Thanks for your advices. Is it possible to do it by myself. It is quite small on the first part of the cylinder.

 

[alimey4u2]

Thanks for your advices. Is it possible to do it by myself. It is quite small on the first part of the cylinder.

Yes.... If these chemicals are commonly available in your country. Extreme caution must be used, IE a well ventilated place ( outside works well) NO smoking & gloves must be worn.... Long exposure will remove paint, so be careful not to damage the finish.... If not available "experiment" with carburetor or brake cleaner.

 

[PhilBolton]

No problem with your English - it's infinitely better than my French or Walloon!

Phil

 

[mamac]

No problem with your English - it's infinitely better than my French or Walloon!

Phil

Thanks a lot...

 

[mamac]

Does someone had the same problem en tried to remove the marks?

 

[bmwrich58]

Does someone had the same problem en tried to remove the marks?

Try an areosol can of "Carb/Throttle Body Cleaner".
While used for cleaning the interior of dirty carburators/throttle bodies,many times the exterior can also be cleanedup of the discolored yellow/brown fuel stains using the same stuff.

 

[mamac]

Thanks for the use of chemical product for carburators but carburators doesn't heat as much as cylinder... I'll try if I can find that can.

 

[Brian ROSEN]

Yellow stains

I had similar stains on an 1100R that I bought secondhand. The previous owner never managed to remove it - and neither did I using all the various solvents and even 'rubbing down' compiound; there must be a simple correct remedy and I would hesitate to do anything at all severe on a relatively new bike until somebody comes up with a solution that they have found sucessful.
(I wonder if this could be caused by some additive in the petrol in Belgium or France ?)

 

[mamac]

In my case it is minor and should be easyly removed. It could stay like that but on a brand new bike it disturb me. I think that if I can't find a solution, I'll made it painted...

 

[Brian ROSEN]

Yellow stains

"I'll made it painted..." No, that is not practical if it is a stain on the cylinder. The aluminium & magnesium is beautifully anodised and you would never be able to match it with a paint. I am sure that there is a simple solution - it is a question of identfying the stain and then finding the right solvent; has your local BMW dealer no ideas? (Or any other motorcycle dealer in fact.)

 

[cookie]

cylinder/head/crankcase/gearbox etc. is painted not anodised.

still be a bastard to match though. doubt carb cleaner will touch it, as it's the actual paint that gets discoloured, not something stuck on the surface.

i'd ignore it.

 

[Brian ROSEN]

"cylinder/head/crankcase/gearbox etc. is painted not anodised." Sorry, I stand corrected. However we cannot expect 'marmac' to ignore these stains now! (Although I did eventually with mine - but it was about four years old at the time.)