Forum

[Smudger]

Noticed that there's a sooty deposit on the inside of the exhaust. I have a CGT 535 that has Cover ed only 1700 miles. Obviously I'm concerned that is burning oil which is a worry. Inside the air box was a film of oil which suggests that it's coming up the breather pipe.
Could this be a result of overfilling with oil?
I did change the oil late last year but have checked the levels after starting from cold and allowing it warm up on a flat surface and then checking the level via sight glass after a few minutes and it's bang on the top marks.
any ideas what could cause this?
Thanks

[Tim NZ]

If you have not given the bike a THRASH for a wee while, then the build up of the amorphous carbon soot in the exhaust pipe is to be expected.


Take a blast the length of a motorway and recheck...

The potential for condensate to get into the air box is similar to the earlier bikes; there is a dip in the main breather pipe immediately after where it exits the cases. Condensate accumulates there and is eventually spat into the air box.


Eliminate that dip in the breather pipe and the situation is negated.

[jefrs]

Some fine soot is normal. Actual oil in the air filter is not. It is very very easy to over-fill with oil, and then it does spit oil out of the breather. Have you topped up? Or maybe they over-filled on first service? It is nigh on impossible to drain all the old oil out and a variable amount, at least 600ml, remains in the motor. Suggest drawing a cup of oil out of the front drain/filter on side stand and only topping up to the bottom mark. Do read the owner's handbook for diabolical and gloriously inaccurate oil-level method; after 3 minutes it may be between the marks but by next morning full to the top and over-full. Under-fill is ok, over filled is bad.

The EFI is very oil-tight so the only way it can burn oil is from the breather which dumps its oil into the clean side of the filter straight into the intake. Been there, done, this.

Italian tune-up, full chat up a motorway for 20 miles will burn a lot of crud out.

RedEx de-coke - add at least double the normal stated amount to the tank and italian tune-up to loosen carbon deposits. Do not use for normal use, not required except as a petrol preservative if you store the bike for months.

[nigelphoto]

Smudger, sooty carbon deposits is normal for modern fuels which are based on part petroleum, part benzene, and part horse manure (or 'animal products' as its referred to in the latest EU directive). Go to your local RE Dealer and stick your finger up all the exhausts of the second hand EFI engined bikes and your finger will be black in the twinkling of an eye! You need to do the second oil change/service at 1,850 miles (3,000 km) so the trick is to warm up for 10 mins, drop the oil from fr and back cranckase plugs and also the pick-up filter (clean the gauze gently as it distorts easily) lean the bike well over to the left and right for a minute or so to try to get all the old oil out . Measure it - should be 2.75l less about 150-200cc for tappet chest/chaincase/various nooks and crannies. Fill with the same amount that came out +/- whatever it takes to get the level is correct in the sight glass . . . 150cc either way isn't going to spoil. Use Motul 15W-50 semi-synth esther based (as per the owners manual) and a new cartridge filter. Promo on ebay at the mo for 4 litres of Motul is £27.95 free delivery. Leave it to stand overnight - check it in the morning and add small quantity of oil until its correct. You can use the sight glass as a guide, but the more accurate way is to do a measured fill.

[jefrs]

Measuring the oil in may not work. I estimate it left a good 600ml in the motor when I drained it warm. Maybe I should have waited until cold again? Tipping the bike left is easy onto the side stand, to the right not so much. Refilling by the amount that came out assumes the correct amount was in it, that is not assured.



What concerns me with this one is oil coming out of the breather. That happened with mine when I over-filled it using the wretched sight glass. Removing the breather tube had oil spitting out of the hole, it is supposed to be displaced air. There is a cast plate below the filler to stop oil splashing, if the oil is above that it will be thrown out. I drained down a little and it stopped occurring.

I had done the 'second oil change' when it started filling the air filter with oil. So I did a third oil change on the same new filter; I drained and then half-filled, ran it and stopped and added eggcups of oil each time until it just showed in the sight glass and then left it to settle. Running it half full it was pretty obvious when the oil hit the pumps because the engine note changed, this would be around 1.5 litres. By next morning the oil had settled to the low mark so I added a little more to bring it to the middle. Which was fine until the next morning when the oil had gone over the top mark, so I had to drain a cup of oil out; it has not been touched since and no oil spits out of the breather. Oils shows between bottom to middle, never over the top mark.



My motor did soot up but for another reason and two tanks full of "RedEX Decoke" (half a bottle each time) got rid of it. I do have a hard soot deposit in the exhaust now but not the soft fluffy black snowflakes, they're gone.



Btw I'm using Mobil 1 full synth (Motorcycle Racing 4T 15W-50) by reason I got over 350,000 miles out of the Volvo 245 on full synth and would have got more if a big lorry hadn't hit it whilst parked.

[Smudger]

Thanks for the replies.

[Smudger]

Could this also be a result of over fuelling as I have a power commander fitted?

[jefrs]

I also have the PCV. Assuming you got yours from Hitchcocks you have a "Bullet" map for CGT. This map covers your normal power band but where the noughts are (use the laptop) it reverts to the OEM ECU mapping, which now does not have an O2 sensor but a resistor and has to run in "open loop" mode.

That map makes a lot of difference. If you switch it off you will notice that you lose the strong thud as you open up, it provides a significant increase in torque.



I've looked at the output from my wide-band O2 sensor running on my AT-200 which sits on top of the PCV and with the AT-200 switched out (not correcting) can see the oem ECU's AFR is all over the place from 10 to 20. Does this matter? Not a lot because it only affects the mostly unused out of map areas, but does include idle. However idle is usually open loop on ECU systems



The PCV map will give you a richer mix, an AFR of 13.2 is suggested for power whereas the ECU is mostly trying for 14.7 (it is lean-burn). However I seriously do not think the PCV will cause heavy sooting, mine was caused by intermittent sparks meaning I was getting unburnt fuel (sorted), in fact I think the PCV will control the mix better and reduce sooting.



If a significant amount of oil is getting from breather to inlet then it will burn that oil and make a filthy black mess. As a temporary measure you could try sticking a cheap breather filter from Halfords on the spigot to see if that has desired effect. Too much oil will reduce engine power (I noticed an improvement when I reduced) and can even damage an engine e.g. hydraulic-lock.

Too little oil is far better than too much. It really just has to cover the pumps.