jsteve1999 Posted December 8, 2016 Report Share Posted December 8, 2016 Hi Everybody I am in the process of re building my 890 2 valve jawa but it will only be run a few times a year and never raced can anybody tell me if it is possible to change from methanol to unleaded to get rid of all the problems with alcohol fuel as far as I understand rejet carb lower compression retard spark are easy to do, but I need to do any drastic internal mods I am also thinking of changing the oil to mineral again to get rid of the problems of leaving castor based oil in the engine over prolonged periods Any help or suggestions would be a help Regards to all Steve Quote Link to comment Share on other sites More sharing options...
Mark Hales Posted March 27, 2017 Report Share Posted March 27, 2017 Hi Everybody I am in the process of re building my 890 2 valve jawa but it will only be run a few times a year and never raced can anybody tell me if it is possible to change from methanol to unleaded to get rid of all the problems with alcohol fuel as far as I understand rejet carb lower compression retard spark are easy to do, but I need to do any drastic internal mods I am also thinking of changing the oil to mineral again to get rid of the problems of leaving castor based oil in the engine over prolonged periods Any help or suggestions would be a help Regards to all Steve Hello Steve. From my drag racing background, an alcohol (methanol) engine runs cooler, so you may have a heat problem with petrol? I "think" the Jawa Metisse uses older 2 valve speedway engines with a pre unit gearbox and they run on petrol. Other than that, all of the above you seem to have a handle on. Mark. Quote Link to comment Share on other sites More sharing options...
Ray Stadia Posted April 9, 2017 Report Share Posted April 9, 2017 Hello Steve. From my drag racing background, an alcohol (methanol) engine runs cooler, so you may have a heat problem with petrol? I "think" the Jawa Metisse uses older 2 valve speedway engines with a pre unit gearbox and they run on petrol. Other than that, all of the above you seem to have a handle on. Mark. Hi Mark, I spoke to a rider at a Pre-65 Scramble (Marks Tey) who had a Jawa 2 valve Metisse and he was using methanol. Clive Quote Link to comment Share on other sites More sharing options...
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