iainb 4,863 Posted July 24, 2021 And have they always done? Share this post Link to post Share on other sites
ch958 2,387 Posted July 24, 2021 is it to do with temperature of the motor? Share this post Link to post Share on other sites
steve roberts 9,241 Posted July 24, 2021 I remember Paul Gachet riding a trial petrol driven bike during a second half event at White City...not sure what became of it? Share this post Link to post Share on other sites
iainb 4,863 Posted July 24, 2021 I wonder what would happen if you ran a speedway engine on petrol? Would it even start? Would it blow up? Share this post Link to post Share on other sites
Pieman72 588 Posted July 24, 2021 Speedway bikes can run on petrol or methanol but the engines are different. Methanol engines run cooler so they need a higher compression ratio and would not be adaptable for petrol. There have been many trials Honda and Kawasaki engines ran perfectly well. If speedway was more flexible there could be an amateur class for petrol powered bikes probably be a lot cheaper and easier to maintain if you could use a cut down stock engine. 1 Share this post Link to post Share on other sites
steve roberts 9,241 Posted July 24, 2021 I also remember that Eric Boocock was part of a team that was experimenting with Honda engines with a view of standardising/cutting costs? Share this post Link to post Share on other sites
steve roberts 9,241 Posted July 24, 2021 5 minutes ago, Pieman72 said: Speedway bikes can run on petrol or methanol but the engines are different. Methanol engines run cooler so they need a higher compression ratio and would not be adaptable for petrol. There have been many trials Honda and Kawasaki engines ran perfectly well. If speedway was more flexible there could be an amateur class for petrol powered bikes probably be a lot cheaper and easier to maintain if you could use a cut down stock engine. ...you beat me to it! 1 Share this post Link to post Share on other sites
iainb 4,863 Posted July 24, 2021 53 minutes ago, Pieman72 said: Speedway bikes can run on petrol or methanol but the engines are different. Methanol engines run cooler so they need a higher compression ratio and would not be adaptable for petrol. There have been many trials Honda and Kawasaki engines ran perfectly well. If speedway was more flexible there could be an amateur class for petrol powered bikes probably be a lot cheaper and easier to maintain if you could use a cut down stock engine. 52 minutes ago, steve roberts said: I also remember that Eric Boocock was part of a team that was experimenting with Honda engines with a view of standardising/cutting costs? I remember the Booey Bikes, I went to a "test" match at Peterborough I think... they kept breaking down if my memory serves me right 1 Share this post Link to post Share on other sites
old bob at herne bay 828 Posted July 24, 2021 I was always told this was about safety - methanol has much lower flammability than petrol. But it burns witha clear flame which when it does catch light makes it harder to spot. Methanol also has a high octane number allowing the use for high compression ratio engines as used in speedway. Conversely it is less enegy dense than petrol hence more fuel is needed and the "mpg figures" for a speedway bike are so poor. Indy carts used to use Methanol after a number ofpetrol fires , but now use ethanol fuel. I 1 Share this post Link to post Share on other sites
OveFundinFan 4,133 Posted July 24, 2021 Does methanol burn cooler too. Share this post Link to post Share on other sites
Tsunami 10,219 Posted July 24, 2021 2 hours ago, steve roberts said: I also remember that Eric Boocock was part of a team that was experimenting with Honda engines with a view of standardising/cutting costs? 1998 1 Share this post Link to post Share on other sites
Rich 75 Posted July 24, 2021 Speedway / Grasstrack engines are designed to run on Methanol as, together with the heavy flywheels used,. it gives the best type of power delivery required for the sport, that is the explosive acceleration from a standing start with a single gear. They can run on petrol with a lot of modifications internally and to the timing and carburation, and quite a few Pre 65 Scramblers / MotoX riders use 2 valve Jawa engines. Engines designed to run on petrol can also be modified to run on Methanol, but many of the 1000cc Sidecar Grasstrack bikes using multi-cylinder Japanese road bike engines, although tuned, still use petrol. 2 1 Share this post Link to post Share on other sites
Pieman72 588 Posted July 24, 2021 Hopefully the was Speedway is morphing petrol could well become an option. Who would have expected Grasstrack bikes on a Speedway track? Share this post Link to post Share on other sites
Rich 75 Posted July 24, 2021 23 minutes ago, Pieman72 said: Hopefully the was Speedway is morphing petrol could well become an option. Who would have expected Grasstrack bikes on a Speedway track? Nothing new, I rode in the South West Speedtrack Championship (for Grasstrack bikes) at Exeter in 1990 and my son rode in a couple of Meetings at Stoke in 2004/5. Next round of the World Longtrack Championship is at Rzeszow Speedway track in Poland. 1 Share this post Link to post Share on other sites
steve roberts 9,241 Posted July 24, 2021 55 minutes ago, Pieman72 said: Hopefully the was Speedway is morphing petrol could well become an option. Who would have expected Grasstrack bikes on a Speedway track? Those were tha days...second halves at Cowley when the likes of Julian Wigg, Ken Matthews and the Drewitt Brothers would ride their grasstrack bikes! Share this post Link to post Share on other sites