Ray Stadia 1,071 Posted September 8, 2015 A Two Valve Jawa. :approve: I recently read that the new Norton, is 2 valves per cylinder, which surprised me with a modern engine! 1 Share this post Link to post Share on other sites
Vince 9,458 Posted September 9, 2015 It's been said before but make a 2 valve Jawa short stroke with light flywheels (which is what would happen) and it wouldn't be even slightly more reliable than what you have now. Share this post Link to post Share on other sites
speedibee 3,091 Posted September 9, 2015 I recently read that the new Norton, is 2 valves per cylinder, which surprised me with a modern engine! I think the new Norton only has exhaust valves , its high pressure direct injection no need for inlets Share this post Link to post Share on other sites
speedyway 0 Posted September 12, 2015 The engines rev 10-15000 rpm. I was reading about F1 engines having pneumatic springs to cope. Would a speedway bike be allowed a gas bottle on them to run some valve springs? I think it would make the engine run faster. Plus the engine wouldnt have to compress the springs so it should become easier to turn and have less losses in the mechanicals. http://scarbsf1.com/valves.html Share this post Link to post Share on other sites
Alan_Jones 1,005 Posted September 15, 2015 Billy Hamill took a GTR engined bike across the El Mirage lakebed at 142.8 mph at the weekend. As a rookie he wasn't allowed a record attempt and had to stay below 150 mph so he'll be having another go at the October meeting. https://pbs.twimg.com/media/COvv_HrUEAAVIMX.jpg https://pbs.twimg.com/media/CO4K3D8UEAAJF13.jpg Share this post Link to post Share on other sites
SCB 0 Posted September 15, 2015 He got 144mph out of a JRM/Jawa so in terms of top end speed theres not a lot between them. Share this post Link to post Share on other sites
oldace 1,678 Posted September 15, 2015 He got 144mph out of a JRM/Jawa so in terms of top end speed theres not a lot between them. Top end speed isnt, and never has been the be all and end all. The dohc 4 valve jawa was much quicker than the weslake, in a race down the motorway the jawa would win every time. Despite that the jawa was rarely the weapon of choice because converting that rpm to forward motion was difficult. Share this post Link to post Share on other sites
SCB 0 Posted September 15, 2015 Top end speed isnt, and never has been the be all and end all. The dohc 4 valve jawa was much quicker than the weslake, in a race down the motorway the jawa would win every time. Despite that the jawa was rarely the weapon of choice because converting that rpm to forward motion was difficult.I agree. Especially as no speedway bike is ever going to 150mph! If they hit 70 they're going some! Plus isn't a speedway bike ( like most racing engines really) more about getting a steady and even power through the revs (or at least through the bit you use!) rather than the more the curved shaped (when looked at on a graph)? Share this post Link to post Share on other sites
Bream 29 Posted September 23, 2015 A bit off topic but still about engines. Is there anyone who speaks czech? Found an article about new Jawa engine. Looks like a two valve? http://www.speedwaya-z.cz/?cat=1248 Share this post Link to post Share on other sites
Ray Stadia 1,071 Posted September 23, 2015 A bit off topic but still about engines. Is there anyone who speaks czech? Found an article about new Jawa engine. Looks like a two valve? http://www.speedwaya-z.cz/?cat=1248 I did press the translate button and did get English words, but still none the wiser really! I think, maybe, it is an engine which needs infrequent servicing, similar to the Gerhard....but might be making 2+2=5! Share this post Link to post Share on other sites
PHILIPRISING 7,298 Posted September 23, 2015 A bit off topic but still about engines. Is there anyone who speaks czech? Found an article about new Jawa engine. Looks like a two valve? http://www.speedwaya-z.cz/?cat=1248 THINK Sam Ermolenko might be involved. Also that it could be 570cc... 1 Share this post Link to post Share on other sites
MattK 3,447 Posted September 23, 2015 THINK Sam Ermolenko might be involved. Also that it could be 570cc... Classic Sam! 2 Share this post Link to post Share on other sites
iris123 20,990 Posted November 4, 2015 This all makes for very interesting reading(well I did get a little bored!!!) concerning Gerhard and a complaint from ex rider Richard Speiser that he nicked his idea.The lawyers are rubbing their hands at least http://www.speedweek.com//sandbahn/news/84022/Richard-Speiser-wurde-um-den-eigenen-Motor-betrogen.html Share this post Link to post Share on other sites
Bream 29 Posted December 5, 2015 (edited) http://dmon-parts.de/shop/GTR-Speedway-Motor/GTR-500-Speedway-Testmotor?source=2&refertype=1&referid=383 GTR 500 is for sale now. What happened to the problems with Speisser? Edited December 5, 2015 by Bream Share this post Link to post Share on other sites
Guest Posted December 5, 2015 (edited) This is off-topic but I would be interested in a response. Marcel Gerhard (Switzerland) was winner of the world long track championship in the 1980s (?) and also excelled on grass tracks. I have a recollection that (a) he also worked at one time for Otto Lamtemhammer and (had a couple of seasons with a German speedway league club? Edited December 5, 2015 by Guest Share this post Link to post Share on other sites
