KB2T,A Warning!

Bob Monkhouse · December 04, 2008, 05:01:56 PM

I\'ll start this with a disclaimer first and foremost having just seen a report from El Presidente regarding synthetic and non synthetic oils. The following are my views and in no way are they to be taken as a critism of the oil concerned. Our Grants FD motor had to stripped after 2000miles due to an unforeseen problem. He\'s been running the engine on KB2T at 125:1 pre-mix after we took the oil injection pump off. My own field of expertise is(or was) tuning two strokes and for all intents and purposes the rotary is a mix of two and four stroke lubrication. My own feelings on running a high powered engine and lubricating the seals with a 10/40 engine oil were such that I felt a good quality two stroke oil would be better for the seals in a rotary. KB2T is used in high revving two stroke engines,particularly Rotax disc valve kart engines. My opinion (for what its worth) was that this semi synthetic two stroke oil would be far superior to crappy engine oil for lubricating the rx engine. However, after stripping the engine the carbon build up on the rotors was far in excess of what i would have expected,in fact was more in 2000miles than the carbon build up from 60000miles before the engine was pulled and rebuilt. My own feelings and other more expert advice from someone who knows a lot more than me regarding oils used in rotarys is that theoil in question is brilliant in two stroke engines( and I personally will continue to use it in two strokes) but don\'t use it in mazda engines, there is a possibility of excess carbon build up which may result in seals sticking, my opinion and mine alone, Bob Monkhouse.

Brett · December 04, 2008, 05:06:52 PM

Thanks for the heads up Bob,

Got any pictures of the carbon build up? I remember what it was like on a rotor that had done 160k....

:wave

memski · December 04, 2008, 05:14:13 PM

Interesting, quick question - who mapped the car? I know a lot of people including myself use Kb2t and I\'m yet to hear of any who have had similar problems with it. Just wondering if any other factors may be at play?

kev-yorks · December 04, 2008, 05:53:24 PM

As above what A/F\'s, heat plugs where you running?
Kevin

clive · December 04, 2008, 10:20:49 PM

Good info Bob, well done never having gone down the remove the OMP route I had never heard of this KB2T "oil" really until now on this post however it\'s good to know the problems you have seen,

Like you this is a personal opinion, but in a two stroke you HAVE to put oil in the fuel but in my head it is better to keep the petrol pure to help atomisation.

Also an FD isn\'t like a bike where you can sit astride it and give it a good ol shake to make sure any seperation is remixed, mind you the bloke below might manage it , he looks like a big boy :cool.

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Prof · December 04, 2008, 10:55:29 PM

I\'m using Quicksilver TCW3 in mine with the OMP adaptor. Seems to be working well, but only time will tell. I get through about 1L every 1000 miles so OMP is working about the same as it would be with engine oil.

The oil is apparently formulated for high revving / higher temp performance outboards and has detergents to help reduce carbonising. Will be interesting to see how this arrangment holds up against premixing or using engine oil.

Hayward North · December 04, 2008, 11:00:04 PM

Iv been using Millers KB2T for a while now and would also like to know the other factors involved if at all posible

HaywardRotary · December 05, 2008, 08:47:19 AM

Speak to me if you want to know more.
Regards
Carl

BlitzBoy · December 05, 2008, 08:55:54 AM

Bob I would say the map on the car needs to be looked at as it sounds it was running real rich, probably on the cruise cells of the map, I doubt the build up of carbon was due to running premix, I have run 2 stroke premix for two years had two strip downs no signs of carbon build up. I
have seen a few engine strip downs on people running premix on KB2T with no carbon build, so please dont assume its the premix oil at fault, find the root cause of the carbon build up as it will happen again.

Bob Monkhouse · December 05, 2008, 09:39:18 AM

Quote from: Brett;562240Thanks for the heads up Bob,

Got any pictures of the carbon build up? I remember what it was like on a rotor that had done 160k....

:wave

Sorry no pics. However Carl has seen the carbon and he was concerned about it. I would have just accepted it as normal. I used to use Castrol \'R\' in the \'70\'s and found it the best two stroke oil there was. I then started using Shell \'R\' in the 80\'s on karts that I was tuning at the time. One point to mention is that race engines are stripped after every race so there is no chance for any carbon build up to occur, my road bikes used to be stripped and re ringed every 4-5weeks(unless I blew the ****ing things up before that which was a regular occurence)!!!One of the things that I liked about \'R\' was that ,when stripped, an engine was coated in it and had to be washed off with neat petrol, this didn\'t happen with other oils at the time and seizures were much more common. The reason originally to use \'R\' in Grants engine was to try and get it through the mot by mixing methanol in the fuel, castor based two stroke oil is the only thing that will mix successfully with it and Matt from York suggested Millers(it ****ed the emissions by the way).I would have continued to use it but for Carls concerns. My own thoughts on lubricating the equivalent of two stroke piston rings with ****ty engine oil are that it is the worst thing(apart from maybe hair gel) that you could use. Engine oil isn\'t designed to keep metal components apart at high temperatures and will \'flash off\' - see what happens in an over heated frying pan-,the oil keeping those parts apart disappears and hey presto, you have a violent seize which ****s the entire engine!!Anyway,what do I know as Mazda have more knowledge on lubricating rotarys than me, I just thought that anyone running on KB2T should know that it \'might not be\' ideal to do many thousands of miles on it particularly in light of my comments above regarding the frequency of engine rebuilds on the two strokes I have experience on. However, if anyone has stripped a rotary that has done tens of thousands on \'R\' and they are happy with it then let me know cos I would rather run with it than GTX!!!Bob.

Bob Monkhouse · December 05, 2008, 09:51:21 AM

Sorry its nowt to do with the mapping its been done(very expertly)by Carl. We have a SUN diagnstic gas analyser at home and its regularly checked on that and is around 1.5-2%CO. If that was a two sroke I would be crying as you need anything from 5-6.5% or its hole in the piston time!!!!Please don\'t let me put anyone off using KB2T these are my thoughts only. One thing I may suggest is Putoline TTS for the rotary on premix. I have recommended this to hundreds of lads on two strokes and NEVER have any problems with it either on road bikes doing tens of thousands or racs bikes for that matter,Bob.

BlitzBoy · December 05, 2008, 09:51:27 AM

......ignore double post

BlitzBoy · December 05, 2008, 09:53:43 AM

Quote from: Bob Monkhouse;562432Sorry its nowt to do with the mapping its been done(very expertly)by Carl. We have a SUN diagnstic gas analyser at home and its regularly checked on that and is around 1.5-2%CO. If that was a two sroke I would be crying as you need anything from 5-6.5% or its hole in the piston time!!!!Please don\'t let me put anyone off using KB2T these are my thoughts only. One thing I may suggest is Putoline TTS for the rotary on premix. I have recommended this to hundreds of lads on two strokes and NEVER have any problems with it either on road bikes doing tens of thousands or racs bikes for that matter,Bob.

What AFRS are you running on it Bob at idle, have you used a Wideband on it?
What AFRS are on cruise?

Bob Monkhouse · December 05, 2008, 10:07:41 AM

Er, two stroke oils haven\'t needed shaking up since before God was born!!!! The quality and design of them these days is such that they stay suspended in the fuel,which is no doubt a good thing for everyone with an FD running premix!!! Anyway, how do you know he\'s a big boy???lol( I hope that means \'lots of laffs and\' not \'lots of luv\' otherwise peeps might be getting the wrong impression of me)!!!Bob.

clive · December 05, 2008, 01:56:33 PM

Quote from: Bob Monkhouse;562438Er, two stroke oils haven\'t needed shaking up since before God was born!!!! The quality and design of them these days is such that they stay suspended in the fuel,which is no doubt a good thing for everyone with an FD running premix!!! Anyway, how do you know he\'s a big boy???lol( I hope that means \'lots of laffs and\' not \'lots of luv\' otherwise peeps might be getting the wrong impression of me)!!!Bob.

Hang on you have met me and you know I actually could be older that god

Reading your post made me remember, why on earth would anyone want to progress beyond Castrol R, don\'t care what it ever did to the engine because once smelt that gorgeous smell lives with you for ever :Thumbs-up:Thumbs-up:Thumbs-up