toofasttim Posted November 12, 2010 Report Share Posted November 12, 2010 Two-stroke engines in personal watercraft in California are certified as "low emission" vehicles but they rely on "direct injection" EFI where the injectors are located in the head and the throttle body modulates air intake and houses sensors. Jon How do they lube the big and small ends and the mains? Quote Link to comment Share on other sites More sharing options...
zippy Posted November 12, 2010 Report Share Posted November 12, 2010 How do they lube the big and small ends and the mains? Bottom end filled with oil like a 4 stroke? But the combustion is 2 stroke? Quote Link to comment Share on other sites More sharing options...
jse Posted November 12, 2010 Report Share Posted November 12, 2010 How do they lube the big and small ends and the mains? As I understand, they use an oil injection system and special formulation oils made just for PWC use. The new oil injection systems are a lot more sophisticated than the old ones most of us remember with distain (and quickly disconnected for competition use). The PWC engines tend to operate at more consistant temps as one is essentially skating across the top of a huge cooling system that remains at a fairly constant temperature. Jon Quote Link to comment Share on other sites More sharing options...
jordi Posted November 12, 2010 Report Share Posted November 12, 2010 Well, was it only Mr Dabster who got to ride this thing at BVM.,s test day? Must be some other poor soul who posts that could take the day off to ride possibly the most talked about new bike of the year. Quote Link to comment Share on other sites More sharing options...
toofasttim Posted November 13, 2010 Report Share Posted November 13, 2010 Bottom end filled with oil like a 4 stroke? But the combustion is 2 stroke? That would be the ideal but you'd lose the bottom end as a pump. Well, you'd get lots of oil being pumped into the cylinder through the transfer ports. As far as I know marine 2 stroke deisels do it by blowing the charge into the cylinder so crankcase compression isn't needed. Quote Link to comment Share on other sites More sharing options...
zippy Posted November 13, 2010 Report Share Posted November 13, 2010 That would be the ideal but you'd lose the bottom end as a pump. Well, you'd get lots of oil being pumped into the cylinder through the transfer ports. As far as I know marine 2 stroke deisels do it by blowing the charge into the cylinder so crankcase compression isn't needed. No transfer ports. All oil stays in bottom end and transmission like a 4 stroke. Basically just mix fuel and air in the compression chamber. All that would be there is the intake port direct to cylinder from carb and exhaust port. Hold on, I may have found a flaw in that theory. As the piston goes up the cylinder does the piston completely block off the exhaust port. If not then there would be a "hole" directly to the bottom end where the oil is and it would all go into the exhaust pipe. But if piston seals the exhaust port this should work. Somebody let me know if this makes sense or if I have had too many I can tear down an engine, replace what is broke and put it back together..........but some of the actual theory and design is a bit lost on me sometimes. Quote Link to comment Share on other sites More sharing options...
toofasttim Posted November 13, 2010 Report Share Posted November 13, 2010 Hold on, I may have found a flaw in that theory. As the piston goes up the cylinder does the piston completely block off the exhaust port. If not then there would be a "hole" directly to the bottom end where the oil is and it would all go into the exhaust pipe. But if piston seals the exhaust port this should work. You catch on quickly Problem is that a 2T HAS to have the air "forced" into the chamber because the piston is going UP when the charge is needed. If a 2 stroke came before the FIMs technical committee today it would be classed as a supercharged engine. Quote Link to comment Share on other sites More sharing options...
baldilocks Posted November 13, 2010 Report Share Posted November 13, 2010 I think from memeory that the Honda version released the fuel and air into the combustion chamber after the piston had closed off the exhaust port on the way back up. That way no unburnt fuel gets out. this is me trying to recall the article in Motor Cycle News from about 1990 and now trying to picture it in my head so forgive if i'm talking more cobblers than usual. Quote Link to comment Share on other sites More sharing options...
jse Posted November 13, 2010 Report Share Posted November 13, 2010 That would be the ideal but you'd lose the bottom end as a pump. Well, you'd get lots of oil being pumped into the cylinder through the transfer ports. As far as I know marine 2 stroke deisels do it by blowing the charge into the cylinder so crankcase compression isn't needed. I know we're getting off the OSSA topic, but in the absence of available info on the OSSA, I guess we'll pull on this thread till it breaks. In years past, both marine and road-going two-stroke diesels have used the supercharger to scavenge the cylinders, mainly the positive displacement "Roots" type, like the GMC. During my teen-age racing years in the 50's/60's we used to patrol the truck wrecking yards for cast off engines and take the superchargers off the two-strokes, the "8/71" being the prize at the time, to use on our drag engines after modifying them somewhat. They were classified as to displaced volume, usually 3/71 to 14/71, with a "3/71" for a "3" cylinder engine of not more than "71" cubic inches per cylinder, an "8/71" for an "8" cylinder engine of not more than "71" cubic inches per cylinder etc. Jon ps. I'm still looking forward to seeing the OSSA in person, I'm sure the details are as nice as the overall unique design. Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted November 13, 2010 Report Share Posted November 13, 2010 Ask away I've been on it. Quote Link to comment Share on other sites More sharing options...
jse Posted November 13, 2010 Report Share Posted November 13, 2010 Ask away I've been on it. Nigel, You've probably rode just about all the available bikes through the years, if you were to compare the OSSA to a modern bike in terms of ergonomics and "feel", what modern production bike is the OSSA most like? Jon Quote Link to comment Share on other sites More sharing options...
johnq Posted November 13, 2010 Report Share Posted November 13, 2010 Well, was it only Mr Dabster who got to ride this thing at BVM.,s test day? Must be some other poor soul who posts that could take the day off to ride possibly the most talked about new bike of the year. Quote Link to comment Share on other sites More sharing options...
johnq Posted November 13, 2010 Report Share Posted November 13, 2010 No Mr Dabster was not the only one to ride it I had a ride at midday and was quite danted to ride it given all the hype/talk over the preceding months of press talk. I jumped on it nervously, it rides softer than other bikes but not dissimilar to an evo in feel, at first I felt that I was higher up than normal but then I realised that this was due to not having a petrol tank in the usual position. Having then ridden it for a short while I became very confident/comfortable on it, the suspension is so forgiving it seems to just float over things. I liked it. Quote Link to comment Share on other sites More sharing options...
trickymicky Posted November 13, 2010 Report Share Posted November 13, 2010 I'm trying to make the advantages of not having a stand outweigh the disadvantages,but i'm not doing very well. Can someone help? Quote Link to comment Share on other sites More sharing options...
toofasttim Posted November 14, 2010 Report Share Posted November 14, 2010 I'm trying to make the advantages of not having a stand outweigh the disadvantages,but i'm not doing very well. Can someone help? No. You got yourself into this mess now you can get yourself out of it Quote Link to comment Share on other sites More sharing options...
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