2T oil

[bigk]

Hello all,
Some thoughts on the following please.
My boys fitted a complete after market crankshaft assy rather than a rod kit, to a KTM85 recently, 4 engine hours later the crank has failed. We removed the crank and sent it back to the supplier who came back with, no fault of the components, failure due to "roller skid", your oil is too good. A phone tennis match later and too their credit, the suppliers are giving us another crankshaft, but still maintain it's no fault of their components, but the oil used. I say OK, please document this on your letter head so I can contact the oil people. No was the answer. I am yet to contact the oil supplier, suffice to say I have over 30 customers, some A grade motocrossers, who use this well known, name brand full synthetic oil with no drama's. The engine component suppliers say they are seeing this regularly with people who use ester based full synthetic oils, regardless of brand. I will be interested to see any thoughts on this.
Cheers,
K

[Tony T]

The theory seems sound as amazing as it sounds. 
The oil has been specifically designed for this application, so it appears that they have failed to produce a product that meets the standards for it's intended use.
If there are so many cases of this, you should be able to get something in writing from the component suppliers that are dealing with this problem.
On the other hand.............. would an OEM crank have failed just the same? And so is the difference in the aftermarket part?
Are genuine parts having the same issues or only the aftermarket ones?
If not, maybe there lies the answer...........
Remember the coloured Bel Ray oil in the 80's that had the crank rebuilders working overtime? 

[Lozza]

It is a possibility for rollers to skid but IIRC the 85 has a cylindrical roller on the stator side, making skid highly unlikely.In what way has the crank 'failed'?

[bigk]

The big end is affected by the oil in the fuel and has failed, not the main bearings.
Cheers,
K

[Hoony]

my first reaction is its a cop out by the component manufacturer to blame an oil company. the old blame game. more so since they would not put this on a company letterhead.

for my piece of mind K man, i am using Motorex Crosspower 2 T, pm me if this was the so called oil or not please when you have time.

[oldfart]

Very interesting post .....love to be a fly on the wall when push comes to shove if it fails again using the same oil
K  I'm using Motul with no problems at all , and seems to be working fine .
Test case will be in a few weeks as I have just dropped a Pro X kit in my PE 250 

[bigk]

Not Motorex or Motul, so no need to stress fellas. Funny thing is the same client has been using the same oil in his KTM 50's & 65's for years without incident. It's just his KTM85's which are widely known to have big end problems anyway, which is one of the reasons we chose the non genuine crankshaft. Funnily enough we fitted the same brand crankshaft to his other childs KTM85 SX which has done more work, with the same oil, with no problems.... yet. Fingers crossed. I use a different synthetic oil from the same company which is specifically designed for air cooled engines in my vintage bikes, and have even used it at 50:1 with no problems. I don't think it is an oil problem myself.

[Marc.com]

I am not buying it, rolling elements would be expected to skid only they are accelerated rapidly without any load, internal combustion engine is always under load, more likely the selection of bearing was the problem, hence the weakness of the design in the first place.

[Maicojames]

While I would run it ( or think it is needed) in a liquid coooled powervalved engine, I stick with the old bean oil-Blendzall Green Label, though I believe in Oz as well as the UK, you can still buy Castrol R30 or R40, or a replacement.

For the old air cooled engines, I have found this by far best, hough you do live with some issues here, like separation in colder weather, though there are additves to help this. For the crank failure, I would be inclined to think a bearing or component ( crank) failure. While it is certainly possible for the suggested scenario-it seems quite unlikely.

[Lozza]

A big end failure won't be caused but the oil. Only if there was no oil in the fuel.

[Tony T]

A big end failure won't be caused but the oil. Only if there was no oil in the fuel.

Now that's interesting, Lozza. Tell us more. 
Me and most of my mates had big end failures in the 80's using the first coloured Bel Ray oil. No problems once we changed. So my thinking is that it is then the oil that caused it.

[mboddy]

Me and most of my mates had big end failures in the 80's using the first coloured Bel Ray oil.

Me too.

[jimg1au]

when i owned a tm300en 2002 i was talking to a large dealer in vic who told me that castrol tts is hydroscipic.thay had a customers bike that the bigend failed due to the oil and lack of use mostly.rust had appeared on the bigend and crankshaft.i ran castrol in guilford and got onto the tech dept.after talking to 3 different people there the 3rd agreed with me saying it is hydroscopic and will atrack moisture if left for a long time.the only factor i dont know is how long the bike was left
cheers
jim

[oldyzman]

Funny u should mention tts, my cousin swears by it, but over the years he rides less and less on a old kdx200-anyway after he nad not ridden for approx 6 months we went for a weekend down past cooma, he was saying that it was not quite right power got less and less and he took the bike to the shop- the issue was a seizing crank not totally seized, i was either big end or mains- i didnt pull it down..
OLDYZMAN

[oz555ktm]

Why would a oil be Hydrosipic if its is a Mineral Oil...

Out of the AIR ??

I have many bike just siting in the shed I do not want any Danage to Them.
if it is a Veg base then ok .
I have been useing Super tt from the about 1980 when it came out
in a white bottle with a red funel on top.

But I run my 495  ,400, all my 250s on 25to 1
and my 125 on 16 to 1

My sons KTM 85 race it for 4 years in canberra and got a 1st for the
year on the 2nd year .
I did not replace the Piston or Rod in the 4 years .
Piston was still in speck ..

But I ran it on supper tt a 25.1 as well ..