Removed downpipes looking for Oil loss clues - photos!

[vonny232]

Right! I took off the plugs and used an endocscopic camera to peek into the cylinders via the Plug holes.

Got some pretty interesting feedback.

Summary:
1) As I posted previously, there was significantly more carbon buildup in the exhaust manifold for Cylinders 2&3 than for Cylinders 1&4.
- This seems to be confirmed by the tops of the pistons 2&3 having noticeably more Oil buildup.
- I separately photographed the piston tops around the inlet valve cutouts and the outlet valve cutouts. Piston 2&3 inlet valve cutouts appeared "cleaner" than the outlet valve coutouts.
- Pistons 1&4 inlet and outlet valve cutouts looked very similar.
2) All 4 spark plugs were sooty and grimy, but not really Oily. This could mean its running rich. I wonder if there is a separate issue with the injectors?

Please see photos of the 4 piston tops, focused on the inlet valve cutouts and outlet valve cutouts.

[vonny232]

I wrapped masking trap around a flat headed screwdriver and pushed it into the cylinder cavity and gently scraped the top of each piston. As expected, there was a small oil residue on the screwdriver after piston 1&4 and a noticeably large oil residue after piston 2&3 (I noticed the residue felt grainy when I rubbed it on my fingers, which must be due to the oil getting scorched by the heat within the cylinders). Cant be good for the valve sealing!

[vonny232]

All 4 plugs were quite sooty. The ceramic insulator was totally black. They were grimy too, but was more of a waxy feel, not particularly oily.

I wonder if there is a separate issue here, with the bike running too rich on all 4 cylinders for some reason. Wonder if the previous owner did something to try and improve performance?

Is there anything I can do to check the effectiveness of the injectors, or is it too complicated?

[KiwiCol]

I'm leaving this to the experts, however, my laymans view is those close up pics of the piston shows damage to the top.  you can see small bits of metal embedded into the top of the piston.  Something has been in there while it's been running, maybe a broken ring? n it's been pulverised & fused onto the piston.

[grog]

Strange story this one. I have no idea but will keep following, interested to see the outcome. My only thought is it looks like motor has to come apart. Sad story.

[vonny232]

Cheers for the responses. Not the best opinions to wake up to.

FWIW, I dont believe thats bits of pulverised metal. I used a screwdriver to lightly scrape the top of the piston and that buildup appears to be carbon (it felt grainy on my fingers).

I will have another look today with the endoscopic camera. I will try and get a view of the walls of the cylinder to see if theres any evidence of damage (I dont believe there is as the performance is good and there isnt loads of smoke).

It is however pretty clear that Cylinders 2&3 are where the Oil is being burned...

Question: If the Oil leak is via the PAIRS o-rings or exhaust valve seals, can the Oil be dragged back into the cylinder as what appears here?

[Andre]

I'll try to cheer you up

These are the colder type spark plugs NGK CR9EK. They don't allow for enough heat to burn off the carbon. Better  use standard plugs (NGK CR8EK).

I don't see damage to pistons on the pics.

2+3 are clearly oily.

As to valve stem seals: Do a leak down test.

As to PAIRS o-rings: Get the f...ing cylinder head cover off and take a look.

[vonny232]

It gets even worse lol

Just spoke to an experienced engine mechanic who has overhauled this engine several times, and the bandit engine as well.

He reckons based on me describing the endoscopic photos that its a problem with the bore or the piston rings for cylinders 2&3 (and its very unlikely to be the valve seals or PAIRS o-rings).

He said the cost of an engine piston overhaul (including possible rebore and piston rings) would be as expensive as buying a replacement engine once time labour and unexpected problems are factored in.

To cut a long story short, he said there was no point proceeding with an overhaul as it could end up swallowing loads of money, and instead recommended to keep it topped up with oil and add some STP additive to try and slow down the Oil loss and drive it as normal :(

Ill replace the plugs though, cheers Andre!

[Andre]

Did you also tell him that compression was equal on ALL cylinders?

Seriously, taking the head cover off and a looksy costs almost nothing in dough and labour.

But he is definetly right when it comes to rebuild vs. replacing.

[vonny232]

Yeah I did, he said all 4 cylinders may be worn (maybe prev owner never changed the oil), but possibly more oil escaping from the oil rings for the inner cylinders. That was one theory, but his broader point was that investigating further could become a money pit.

Yeah ill take the valve cover off anyway (as you say, its worth a looksy), need to buy some liquid gasket first!

[Andre]

AND Yeah all 4 cylinders may be worn but NOBODY will know unless a compression test is done using a CALIBRATED tester!

I used two compression testers of unknown calibration status on a good engine. One showed 152 PSI while the other showed 181 PSI. By 152 PSI (156 being the cut-off) Suzuki recommends a rebuild, while 181 is 10 PSI above standard compression of the 14 engine.

Not doing basic tests correctly will certainly lead to unneccessary repairs or replacement engines!

[vonny232]

I might just buy a compression tester myself, they dont seem too expensive 

[Andre]

Question: If the Oil leak is via the PAIRS o-rings or exhaust valve seals, can the Oil be dragged back into the cylinder as what appears here?

Unlikely

[grog]

Vonny, seems you have three choices. No easy solutions except one. 1: Pull your motor down and rebuild as needed. 2: Source another complete motor. 3: Youre only using 1 litre around 2 th ks. Just top it up. No smoke, no leaks, just do it. As i said b4, top it up once, next time is oil change time. Not being blunt but i am. Motor still has enough power? If yes, just ride it & enjoy. Much easier option for you, mentally and money wise. Just my opinion.

[vonny232]

Ok folks. Yeah the choices are not great.

In the short term, I will do the following:
1) Take off the rocker cover and check the valve clearances (might as well while its winter with the tank off).
2) Get another compression test to see if the 130PSI reading is accurate or not (either a 2nd opinion, or ill buy my own and test it). - Question, can you buy "calibrated" compression testers?
3) Put the bike back together and use an additive (like STP?) to try and reduce the Oil leakage.

In the longer term ill keep an eye out for an affordable engine. Maybe for next winters project.