kimpybugalugs Posted February 9, 2008 Report Share Posted February 9, 2008 (edited) In the process of converting my TY175 from autolube to premix I have had differing advice on pre mix ratio. Suggestions ranging from 40:1 to 70:1. It will be used in twin shock trials so mostly slow speed work in 1st and 2nd gear. I will run it on a synthetic oil (Castrol TT). I would like to know what ratio others have used and for how long? I'd like to avoid it blowing up but also would like to avoid it oiling up. Any advice/opinion/debate etc. greatly appreciated. Cheers. Edited February 9, 2008 by kimpybugalugs Quote Link to comment Share on other sites More sharing options...
feetupfun Posted February 9, 2008 Report Share Posted February 9, 2008 If your jetting is good, you can run as much oil as 20:1 and still not have oiling up problems. If your jetting is too rich, you can have oiling up problems with much less oil in the fuel. Where I live, Castrol TT is not a synthetic oil. Maybe you mean Castrol TTS? I have been using mineral based, full synthetic and semi-synthetic two stroke oils in the premix for my TY175 since 1976 and all my other twinshock trials bikes since I got them (ranging from 4 to 13 years ago). I have consistently run 33:1 fuel:oil with all three types of oil and have never had oiling issues. My sparkplugs last many seasons and never foul. I eventually replace them because of electrode wear. I have noticed that modern synthetic oils produce an almost invisible exhaust plume while the mineral based oils from the 1970s produced a more visible plume at the same ratio. I'm sure people have run their bikes on less oil and also not had problems but I'm just telling my story. David Quote Link to comment Share on other sites More sharing options...
kevin j Posted February 9, 2008 Report Share Posted February 9, 2008 I run 50 or 60:1 with synthetic oils in the air cooled yams. 80:1 in the water cooled moderns. k Quote Link to comment Share on other sites More sharing options...
kimpybugalugs Posted February 9, 2008 Author Report Share Posted February 9, 2008 Yes I should've put Castrol TTS. Thanks for the info David and Kevin. It's interesting to get the different opinions - so far on this thread we have 33:1, 50:1 and 60:1. I am interested in the reasons people have picked a particular ratio. Was it recommendation? Personal experience? Shop advice? Something else? I think (at the moment) I'll go with 51.5:1 (probably 50:1 will be easier to measure) as it's mid way between 33:1 and 70:1 and these are the top and bottom of advice I've had so far. Any further comment, advice or debate greatly appreciated. Cheers. Quote Link to comment Share on other sites More sharing options...
scottt Posted February 9, 2008 Report Share Posted February 9, 2008 I run mine at 50:1, Birkett told me that, never had any problem with it. Quote Link to comment Share on other sites More sharing options...
mollygreen Posted February 10, 2008 Report Share Posted February 10, 2008 20:1? 33:1? 50:1? What are you lot doing? Choking everyone and everything around you, that's what! This is 2008. There are now quality oils available these days that are designed for air-cooled as well as water-cooled two strokes that can be run at 100:1. I have used Amsoil Saber Professional 100:1 pre-mix for years. I ride my TY250 Twinshocker on the road without any problems at all. With oil mix ratio's like you are taking about, are you surprised that everyone wants to ban the two stroke? Run 100:1. Do yourself and the environment a favour! Quote Link to comment Share on other sites More sharing options...
kimpybugalugs Posted February 12, 2008 Author Report Share Posted February 12, 2008 100:1 makes me nervous. Has anyone else used this Amsoil Saber Professional stuff? As for saving the environment - burning any fossil fuel is bad so leaving the oil out (as with 4 strokes) is still bad for the environment. Maybe we should park the motorbikes up and go bicycle trialing? I wouldn't have to worry about pre mix ratios either. Quote Link to comment Share on other sites More sharing options...
feetupfun Posted February 12, 2008 Report Share Posted February 12, 2008 Kimpybugalugs I just remembered something else about 2 stroke oils that might influence what you use. While full synthetic premix oil generally provides the lowest smoke and engine deposits formation rate, it does not protect the rolling element bearings from corrosion during non-use periods as well as semi-synthetic and straight mineral two stroke oils do. So if you only ride your bike once in a while and store it exposed to high humidity, or if you are not able to run the motor after washing your bike, you may want to consider using semi-synthetic oil. If you ride at least every week and keep your bike in a low-humidity environment, it probably doesn't make any difference in this regard which oil you use. David Quote Link to comment Share on other sites More sharing options...
kimpybugalugs Posted February 12, 2008 Author Report Share Posted February 12, 2008 Thanks David. No humidity problems where I am and it'll get regular runs so synthetic will be fine. In the late 70s/early 80s I had some friends that ran their YZ80(F I think?) on Castrol R - lots of smoke but I loved the smell of that stuff. Anyway, at the moment I'm still thinking Castrol TTS at 50:1 (sorry mollygreen) but am still open to further advice, debate or comment. Cheers. Quote Link to comment Share on other sites More sharing options...
kevin j Posted February 13, 2008 Report Share Posted February 13, 2008 Wasn't castrol R the full racing castor bean oil product? Great lubrication but nasty if left in the engine a week or more. Lots of maintenance and flushing on shutdown, etc. required to get it out of the system before storage. The synthetics have sort of taken over the high performance market. I don't know anything about 2s racing anymore. jon stoodley be the man... k Quote Link to comment Share on other sites More sharing options...
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