Why did engine make gunge

Posted: Thu Jan 14, 2016 5:01 am

Ok a brief history of the bike is PO rebuilt the engine replacing
Main shells
Big end shells
Piston rings
Oil seals
Cases Block and Head cleaned and resprayed all put back together and looking like a brand new 30 year old if you know what I mean. When he got the engine started she needed very little work to have her ready for a run on the road the usual of a cylinder and carbs needing balanced. I don't live that far away from him so he decided that the first run on the road after a 2 year lay up would be to my house but about a mile out the oil light started to flicker so he pulled over and give me a call and we pushed her to my house. First thing to check was the oil level it was at the right level but it was dark and had a silvery sheen to it so while she was still warm we drained the oil and instead of finding clean oil it was black with a silvery sheen and it smelled of fuel. He told me that the carbs took a while to stop leaking out the over flows but not enough to find its way to the oil.
Next was the sump to be removed and what we found was what can only be described as black grease with a silvery sheen to it my first thoughts are that its the Babbot of the shells
The next day I had a look at the drained oil to find that the dirty part had separated and was settled at the bottom of the drain bowl like a black grease.Took of the valve cover to find the same thing that were the oil pools in the head dip your finger in and black sludge. The engine is now out of the frame and completely stripped down to find the sludge every place were the oil pools and that all the shells are showing copper. Crank and Cams are scrap along with the Head and the PO was so devastated he just walked away and told me to keep her because on the strip down we were expecting something to really jump out as to what went wrong. The oil pump is also scrap but what I found was that it had been assembled with the dots on the main ( large rotors ) facing towards the engine when the manual says to face them to the outside casing of the pump would having this the wrong way trash the engine also PO said that he had to replace the A marked cam bearing cap as the original one had split and a piece of the threaded part was missing so it couldn't be repaired using a helicoil could the wrong clearance here also trash the engine. Any input would be welcome as I now have all the parts to start the rebuild and I don't want this to happen again
I have tried to attach photos and a video of the engine being run for the second time prior to having the carbs balanced. Hope someone on the forum can point me in the right direction as to find out why this all went horribly wrong for PO.

Posted: Thu Jan 14, 2016 8:49 am

Id bet the black was burned aluminum in the oil. Did the bearings spin in the cases? Or do you have the crank out yet.

Posted: Thu Jan 14, 2016 9:23 am

Could the fuel have thinned the oil enough to reduce its effect and then trash the bearings?

Regards,

Max

Posted: Thu Jan 14, 2016 3:05 pm

Hi thanks for responding. The engine has been stripped down and the crank is removed and the bearings were all snugly in place none had spun but they were all showing the copper.
As far as having fuel in the oil correct me if I am wrong but looking at the carb float bowl setup that if the carbs were to over fill due to a stuck needle or dirt the fuel would go out the over flow before it got high enough to travel down the the carb throat PO said that the engine was fed fuel from an auxiliary 1litre fuel bottle on first start up and was only on as the engine was running he also said that the fuel leaks at the carbs was short lived with a few taps on the bowls with a screwdriver help them to settle. Before the engine was removed I did a compression test thinking that the new rings hadn't seated and maybe there was a bit of blow by but the test came back solid at 160ish across all four

Posted: Thu Jan 14, 2016 3:24 pm

Sorry guys my photos seem a bit big slowly getting used to this posting lark but here are more of the bearings.

Hawk Joined: Aug 17, 2013 Posts: 302 Location: Devon. UK

I've seen that kind of mess in a 900 engine only once before.
It's blast media.
my guess is the previous owner had the cases cleaned for painting by having them media blasted and then failed to clean out all the oil galleries properly before building the engine up.
There are a few oil galleries in the cases that are very difficult to clean out properly, and if not done properly then the oil carries the blast media to every bearing surface and wrecks the engine.

Edit.
If you are intending on rebuilding this engine with any parts that haven't been wrecked then make sure every re-used part including the cases are thoroughly ultrasonically cleaned.

CB1100F Joined: Jun 18, 2006 Posts: 2529 Location: UK

Stueecat wrote:

I've seen that kind of mess in a 900 engine only once before.
It's blast media.
my guess is the previous owner had the cases cleaned for painting by having them media blasted and then failed to clean out all the oil galleries properly before building the engine up.
There are a few oil galleries in the cases that are very difficult to clean out properly, and if not done properly then the oil carries the blast media to every bearing surface and wrecks the engine.

Edit.
If you are intending on rebuilding this engine with any parts that haven't been wrecked then make sure every re-used part including the cases are thoroughly ultrasonically cleaned.

Yes that could be the case, the inside of the sump looks like its been blasted, and if the oil gallery plugs were not removed from the upper crankcase and everything not flushed out that will make a right mess with blast media being pumped round the engine

Hawk Joined: Aug 17, 2013 Posts: 302 Location: Devon. UK

Thing is keith, I recognised the mess as soon as I saw it.

I did exactly the same thing during a 900 rebuild 25 years ago. On that occasion my engine did exactly the same thing, ran fine for a short period of time, then the oil light came on, then the engine died. When I pulled it apart I found the exact same mess inside.
Live and learn eh !!

Posted: Thu Jan 14, 2016 11:08 pm

Hi guys thanks for response with the wealth of experience on the forum I knew someone would have come across this before. Will check with PO to see how he had his parts cleaned. I have built a few engines in my day and it is amazing what the oil will pick up from what looks to be a clean rebuilt engine. Will get the cases out and work out how the oil works through them and get cleaning. Thanks again for the input and I will keep you posted on my progress.

Posted: Fri Jan 15, 2016 10:47 pm

You definitely have some type of medium that has gone through everything...... So besides changing out parts that have been destroyed you "MUST" remove every cap, plug and restrictor in the cases to clean and brush thoroughly every nook and cranny in addition to the obvious oil galleries ................... and repeat until you can eat your dinner off any part of them.

Note (1) The oil restrictor supplying the primary shaft (to get this out use a 7 mm tap and cut a thread into it so you can pull it out) This restrictor is feed by the main oil delivery line coming from the oil filter and any medium can collect under it and there is no other way to clear it other than the restrictor removal.

Note (2) Remove the end caps from the camshafts and clean inside them !!! This is missed by many and material can and will collect here.......... So remove it.

Captain

Posted: Sat Jan 16, 2016 8:42 am

Captain wrote:

Note (2) Remove the end caps from the camshafts and clean inside them !!! This is missed by many and material can and will collect here.......... So remove it.

Captain

that was one of my bucket list questions - where do you get replacement end caps ? is it a spare part

Posted: Sat Jan 16, 2016 1:43 pm

Thanks for the heads up Captain another question I will need to ask PO is do you have a small resistor oil jet in a jam jar somewhere in your garage by any chance for as you can see in photo it's not there. This no doubt will have contributed to more loss of oil pressure at the crank and cams.

Posted: Sat Jan 16, 2016 10:03 pm

I just did a VW motor for a guy that had the cases blasted. I specifically told him I wouldn't do the engine if he did. He did it anyway and then told he he'd cleaned it perfectly. All of the oil gally plugs were loose, (some VWs have threaded oil plugs) so I assumed he'd cleaned it.

Luckily for him, the thing leaked from case center-line and I had to re-split the cases to get it sealed up and what I found...a huge very annoying mess. He got lucky. He said it only ran for a minute because it wouldn't idle. Turned out the guys that rebuilt his carbs didn't bother to reset a initial throttle setting and the blades were closing entirely. But it was enough to fill the bearings with glass bead but not lock up the engine.

I pulled every plug in the cases and blasted that thing in the high pressure car wash for an hour. Through every oil passage etc. Exactly the way I told the owner to do..but he didn't.

All new bearings and a surgical cleaning of everything else.

I'm making a new labor sign

Labor $95 per hour
If you watch $120
If you help $145
If I have to redo your work $250

Posted: Tue Jan 19, 2016 3:27 am

Had a chat with the PO and he said that he had the whole engine vapour blasted Head Block and Cases he also said that he took care to plug the oil galleries in the cases and then he flushed the cases with a water hose and air pressure. I have an aircraft factory at my disposal so I can take the engine parts to work a bit at a time and have them cleaned in the degreaser and hot solution baths.
My new friends at DSS have already sourced me a oil resistor jet that's missing so once again THANKS for all the input from you guys and I will continue to post my progress in the What did you do to your bike today thread. Cheers Paul