January 11, 201412 yr Hello, Wonder if anyone can help me i have a 1992 gas gas contact 250 that im rebuilding im just wondering what the best 2 stoke oil and fuel/oil ratio to use in it? thanks Russell
January 11, 201412 yr i would use 70 to 80 ml of putoline trials 2 stroke oil in 5 l of the high octane petrol
January 11, 201412 yr Author Thanks for the info, should it be putoline pro, 2T etc or does it not matter?
January 11, 201412 yr Author The guy i got it from said to run it at 25:1 which would mean 200ml of oil to 5 litres petrol which to me seems very rich, he also told me to run it on castor based mineral oil i take it he didnt have a clue??
January 11, 201412 yr My 98 contact runs @66:1 (same ratio as nelly1 above) smokes a lot @50:1 I use putoline mx7 or motul as mentioned in the link above, have a read of that, basically find a mixture that suits your riding. maybe start at 50:1 then go from there!?!
January 11, 201412 yr Author thanks i will start from 50:1 as suggested. I did read that link posted but there is a lot of options to choose from.
January 13, 201412 yr Castor based mineral oil! I knew a grasstracker who had SAE 50 castor oil for his 4 stroke total loss grass tracking engines. He used the same stuff in his 250 Bultaco trials at 25:1. Totally gummed up the engine and the big end failed. Following some lengthy discussion on another thread about oils and mix ratios I contacted 3 oil blenders / manufacturers, all of whom produce mineral, semi and fully synthetic grades of 2t. None gave definitive mix ratios saying follow engine manufacturers / tuners guidance on oil specs and mix ratios. 2 no longer suggest any ratio on their packaging, the other says according to manufacturers (of engine) guidance up to 50:1 2 said semi synthetic was more than adequate for trials and fully synthetic was not required. One was quite adamant on this pointing out their fully synthetic was a racing oil and trials engines were not racing engines. Another pointed out that their semi synthetic was their recommendation for older air cooled MX and trials engines. One pointed out that the additive package and oils specification / approvals was more important than the base oil type.
January 13, 201412 yr Author i have a couple of 80's 2-stroke go karts and they run on Shell Advance R castor oil other than that have never heard of it being used for anything. Thanks for the advise, i will go with the 50:1 semi synthetic and see from there. Thanks again. Russell
January 13, 201412 yr Author Sorry lads have another question!!! is it ok to use fork fluid in the rear shock on my bike? Or do i need special fluid??
January 13, 201412 yr Sorry lads have another question!!! is it ok to use fork fluid in the rear shock on my bike? Or do i need special fluid?? Is it April already ?? TLTEL
January 13, 201412 yr Sorry lads have another question!!! is it ok to use fork fluid in the rear shock on my bike? Or do i need special fluid?? The answers are probably "no" and "yes". Jon
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