Oil?

[Mcallan]

Hi guys-ladies just bought my first trials bike a gas gas txt 300 and I’ve still go 2 stroke oil in the garage. Castor 927. What’s your thoughts and would you recommend a mix ratio? 

Thanks  

[faussy]

Possibly too good for trials if that makes sense. Personally i prefer a thinner oil. But for the 927, id say around 70 to 80:1

Edited January 22, 2019 by faussy

[peterh]

Hi, I have used a 927 castor oil and here are my thoughts. I was using 80:1 in a 98 Octane petrol

Smells great - brings back memories and of course is environmentally friendly being a castor oil.Is promoted for a high performance 2-strokes and doesn't suffer the old problems of sticking up rings etc. But is a trials engine a high performance 2-stroke engine? We all like to think the rider is a high performance rider but do we put the engine to the same high performance requirements of motocross or karts.

Advantages:

1. smells great (for those waiting in line behind you waiting to ride a section) - might put them in 2-stroke heaven or higher and then they muck up their ride - as long as they do not float through.
2. those using mineral based or fully synthetics won't be able to "borrow" your pre-mix as strongly recommended not to mix castor with others
3. I was happy that I thought it helped ignition and consistency of idle - or at least there was no detrimental effect.

Disadvantages:

1. You won't be able to use your fellow riders mineral or synthetic premix if you just need that little extra to complete the next lap of the trial.
2. While I found that initially e.g 3 months, I could still see the arrow and size of my piston with a bore scope but after 6 months or so that disappeared and when I did have to take the barrel off the piston (for another reason) the piston dome and compression insert were caked with a really hard carbon which took a lot of soaking and gentle plastic card easing to decoke my piston dome and compression insert.
3. There was also a lot of really hard caked carbon build up in the exhaust header - took a good amount of heat (butane gun - didn't have oxy-acetylene) and a wire rope abrasion inside to decoke the header (titanium header pipe)
4. Not sure whether it was the 927 or I did not change my muffler packing often enough but when I did it was more oily than I had experienced previously - always having used 80:1 ratio
   • 927 has a high Flash Point temperature - 218°C - might mean less oil burnt off in a trials bike i.e more spread through header, mid-section and muffler

I changed back to a fully synthetic with a much lower Flashpoint. Last clean of piston crown and compression insert was a very easy clean. Will see what transpires with the muffler packing in the next 6 months.

Those are just my thoughts and experiences.

A good link here: http://www.dragonfly75.com/motorbike/oil.html

Edited January 25, 2019 by peterh
updated