2 Valve or 4 Valve ?

[THE DEAN MACHINE]

1 hour ago, Sings4Speedway said:

Agree with everything above, the silencers are shocking and the tyres are dire. These have been introduced as money spinners rather than improvements to the sport. Sadly forcing engines changes is unlikely to take and the rev limiter idea was coming in 3 years ago and has moved nowhere (plus is still another rider cost).

A usable tyre is whats need and 1 per rider per meeting, none of this they shred so have 2 nonsense. If the bikes are destroying the tyres then the riders will have to look at ways of managing it (via engine/setup changes). Riders will change their equipment, riders have changed their equipment but they need an incentivised reason to do so rather than just pandering to their demands.

The limiter was introduced and the limit is set higher than the actual revs achieved during a race, I brought a new anlas tyre last year for the upright championship on the Isle of Wight and used it again this year, so it can do 10 races when the limit is lowered to around 10,000, as bad as the tyre is it is being expected to do a burn out for 5 mins at 11,000+revs, that’s asking a lot of any tyre 

[FAST GATER]

I remember we used to have new tyres (Dunlops were in favour then) and change to a cut tyre if the said rider felt it was an easier race to win ,we worked on the basic that we set the bike up out of the starts or to suit the track if both were achieved it was a very rare  occasion .

We only started doing much to the ignition timing during meetings  when we were using Weslakes .

 

Edited October 22 by FAST GATER

[AFCB Wildcat]

13 hours ago, THE DEAN MACHINE said:

The 2valve/4 valve argument is largely redundant, it’s has no real bearing on the current state of the sport, bikes are no faster now in real time speed than they were 40 years ago, what has changed dramatically is the speed of the back wheel, engine revs now are ridiculously and unnecessarily high, japs revved up to around 6000, 2valve Jawa revved up 7500 revs, 4 valve weslake were up to around 9500 and upright GMs to around 11500, the modern GM can max out at around 13500 revs although during a race you would be lucky to hit 12,000 revs but as I said earlier overall times over 4 laps haven’t really changed, the increase in revs is causing the tyres to disintegrate and it’s causing the tracks to disintegrate and it’s also made the bikes flat out power rather than throttle control, the modern silencer has reduced the usual power down to about 2000 revs, anything out side that usable rev range and you will not go anywhere, imo the introduction of a 10,500 rev limit via the rev limiter, a better tyre and a better silencer would make the bikes easier to control, you could also do things like smaller cam lift or heavier flywheels or softer compression to reduce the overall revs of the engine, it’s not too hard to implement these measures but unfortunately the sport is run by the riders for the riders via the tuners so don’t expect anything to change anytime soon 

I agree that overall times over 4 laps haven't changed significantly since the 2 valve era, so what lead to riders going in this direction to where we are now?

It must be factored in though, that the 2 valves were un-silenced, so was the move to higher revving engines a way to combat the restriction of the silencer when they were introduced?

It seems that every time a new silencer is introduced, that engines have to change to adapt. Or are there other factors that have led us here?

 

Edited October 22 by AFCB Wildcat

[THE DEAN MACHINE]

1 hour ago, AFCB Wildcat said:

I agree that overall times over 4 laps haven't changed significantly since the 2 valve era, so what lead to riders going in this direction to where we are now?

It must be factored in though, that the 2 valves were un-silenced, so was the move to higher revving engines a way to combat the restriction of the silencer when they were introduced?

It seems that every time a new silencer is introduced, that engines have to change to adapt. Or are there other factors that have led us here?

 

It’s the basic principle of the more they rev the louder they are and the original silencers were straight through ones till about 10 years ago, then they put a metal block half way along the silencer which caused extra back pressure and heat so engines had to be altered to suit the back pressure and heat shields were introduced because the silencers were getting so hot, this was the cause of the cheating when riders were drilling holes in the block and then the current silencers have the same hole in them that the cheaters were doing, it’s writing stuff like this and reading it back you realise how stupid speedway really is 

[Youhave2minutes]

15 hours ago, THE DEAN MACHINE said:

The 2valve/4 valve argument is largely redundant, it’s has no real bearing on the current state of the sport, bikes are no faster now in real time speed than they were 40 years ago, what has changed dramatically is the speed of the back wheel, engine revs now are ridiculously and unnecessarily high, japs revved up to around 6000, 2valve Jawa revved up 7500 revs, 4 valve weslake were up to around 9500 and upright GMs to around 11500, the modern GM can max out at around 13500 revs although during a race you would be lucky to hit 12,000 revs but as I said earlier overall times over 4 laps haven’t really changed, the increase in revs is causing the tyres to disintegrate and it’s causing the tracks to disintegrate and it’s also made the bikes flat out power rather than throttle control, the modern silencer has reduced the usual power down to about 2000 revs, anything out side that usable rev range and you will not go anywhere, imo the introduction of a 10,500 rev limit via the rev limiter, a better tyre and a better silencer would make the bikes easier to control, you could also do things like smaller cam lift or heavier flywheels or softer compression to reduce the overall revs of the engine, it’s not too hard to implement these measures but unfortunately the sport is run by the riders for the riders via the tuners so don’t expect anything to change anytime soon 

Thanks for highlighting the real issues regarding the rev etc situation. It’s always nice to hear from an ex rider who is more in the know of how today’s machines work. However I still stand what I’ve seen in the earlier days of more team riding and better control of the bikes, love to see the racing where you could throw a blanket over the four riders as the racing was that close. I feel today it’s gate and clear off. I guess there won’t be any changes even though the injury list will stack up.

[THE DEAN MACHINE]

1 hour ago, Youhave2minutes said:

Thanks for highlighting the real issues regarding the rev etc situation. It’s always nice to hear from an ex rider who is more in the know of how today’s machines work. However I still stand what I’ve seen in the earlier days of more team riding and better control of the bikes, love to see the racing where you could throw a blanket over the four riders as the racing was that close. I feel today it’s gate and clear off. I guess there won’t be any changes even though the injury list will stack up.

My point to your point was you could make the bikes like they used to be and make the racing closer/better with the modern bike, the number of valves isn’t the problem, it’s the way they are set up,flywheels, cam’s everything on the modern engine is there to make it rev, I’m not sure of exact weight but a modern GM is probably 1/2 the weight of a jap. I raced a jap at the weekend and you really have to man handle the bike into the turns, the modern bike pretty much goes in to the turns on its own but so did weslake’s and other uprights 

[Youhave2minutes]

1 hour ago, THE DEAN MACHINE said:

My point to your point was you could make the bikes like they used to be and make the racing closer/better with the modern bike, the number of valves isn’t the problem, it’s the way they are set up,flywheels, cam’s everything on the modern engine is there to make it rev, I’m not sure of exact weight but a modern GM is probably 1/2 the weight of a jap. I raced a jap at the weekend and you really have to man handle the bike into the turns, the modern bike pretty much goes in to the turns on its own but so did weslake’s and other uprights 

Thanks for that👍

[Technik]

2 Valve/4 valve, Upright/Laydown the difference is the progress that Riders/tuners want & it appears they want an engine that revs way more than it is required to do so. many things have changed over the years in speedway & we all look back to say how great it was way back when.

Todays engine as a a laydown is much the same as it was 40 years ago. The insides have changed, to achieve the massive amount of revs todays engine make they have moved to a short stroke engine which makes for smaller flywheels & bigger pistons to get towards 20,000rpm & then fit a limiter to reduce it to 13,500rpm. The only time an engine might go over this is on the start line when the engine is not under load.

The quickest solution would be to limit the bore size this would increase the stroke to make 500cc & dramaticly reduce the upper rev limit also reducing potential noise levels. With lower revs it would also reduce maintenance costs for the rider. This would also increase the useable rev band making the machine more rider friendly for those that choose throttle control over twist"n"go

[Garry1603]

I thnnk it would be good if speedway could follow a system like Formula One where the 'formula' is revised and updated every five years or so. Whether it's 2 or 4 valve or upright or laydown I'll leave to more technically minded people, but it would make the sport interesting and relevant.

As long as there is a sufficient lead in period to the next formula there would be no issues with equipment becoming obsolete, they would just get old and be out of date anyway.

It hasn't done Formula One any harm to introduce elements to the sport which effectively slow down the cars - why not speedway?

 

 

[THE DEAN MACHINE]

1 hour ago, Garry1603 said:

I thnnk it would be good if speedway could follow a system like Formula One where the 'formula' is revised and updated every five years or so. Whether it's 2 or 4 valve or upright or laydown I'll leave to more technically minded people, but it would make the sport interesting and relevant.

As long as there is a sufficient lead in period to the next formula there would be no issues with equipment becoming obsolete, they would just get old and be out of date anyway.

It hasn't done Formula One any harm to introduce elements to the sport which effectively slow down the cars - why not speedway?

 

 

Because speedway is run by the riders, F1 isn’t run by the drivers, the solid block tyre was an attempt to slow the sport down and was met with dummies out the pram from all concerned, the sport will continue to run away cost and speed wise because there is no Bernie eccleston type character at the helm dictating the sport, there are various examples of expensive parts that have had no beneficial impact for the sport, tubeless tyres and the wheels needed,, karger ignition boxes, blixt carbs,hydraulic valves being some examples 

[Chadster]

This has been a very interesting thread for someone like me who has not much interest in machinery and even less knowledge about it. It's a shame because when I got interested in speedway in the late 60s there was little talk about the machines beyond whether someone was riding a JAP  or a JAWA and set up seemed to be about picking the right gearing. So speedway could sell itself as a motor sport for people who weren't much interested in motors. Now it seems you have to be a mechanical expert to take part or pay someone a lot of money to be one for you.

[THE DEAN MACHINE]

11 minutes ago, Chadster said:

This has been a very interesting thread for someone like me who has not much interest in machinery and even less knowledge about it. It's a shame because when I got interested in speedway in the late 60s there was little talk about the machines beyond whether someone was riding a JAP  or a JAWA and set up seemed to be about picking the right gearing. So speedway could sell itself as a motor sport for people who weren't much interested in motors. Now it seems you have to be a mechanical expert to take part or pay someone a lot of money to be one for you.

Speedway is full of BS, half the riders haven’t a clue why they use something they just see a top rider use it and think they have to as well, the riders at the top understand that speedway is very rider specific, what works for 1 rider won’t work for another and around 50% of riders throw money at something that doesn’t work, I remember when I worked for Adam skornicki him telling me at a meeting his bike packed up and Jason crump lent him a bike, he said it was the worst bike he had ever raced, it didn’t want to turn but obviously it worked for Jason 

[Technik]

So much has changed within the sport, the biggest is "The Sump" when engines ran oil on a total loss system the used oil would go onto the track making the surface bind together then with the the oil catcher in the 80's followed by the recirculating oil system less & less oil went onto the track & over time the tracks became very loose & slick as there was no binding agent (Waste oil) this has in the past seen track men pour oil onto their tracks to reproduce the surface they require. Their actions have been to over oil or use incorrect oil & now the enviromentalist's have put a stop to it all.

todays engine would struggle to work on a 1970 track as much as a 1970 engine would be poor on the slick surface we have today

[THE DEAN MACHINE]

5 minutes ago, Technik said:

So much has changed within the sport, the biggest is "The Sump" when engines ran oil on a total loss system the used oil would go onto the track making the surface bind together then with the the oil catcher in the 80's followed by the recirculating oil system less & less oil went onto the track & over time the tracks became very loose & slick as there was no binding agent (Waste oil) this has in the past seen track men pour oil onto their tracks to reproduce the surface they require. Their actions have been to over oil or use incorrect oil & now the enviromentalist's have put a stop to it all.

todays engine would struggle to work on a 1970 track as much as a 1970 engine would be poor on the slick surface we have today

At Carmarthen in 2002 we had shale from the GP at Cardiff and it wouldn’t bind so me and Gordon meakins went at midnight to roll waste oil drums all over the track and then prep the track, next morning it rained hard and the track was a nice rainbow colour but it did bind the shale 

[Garry1603]

1 hour ago, THE DEAN MACHINE said:

Because speedway is run by the riders, F1 isn’t run by the drivers, the solid block tyre was an attempt to slow the sport down and was met with dummies out the pram from all concerned, the sport will continue to run away cost and speed wise because there is no Bernie eccleston type character at the helm dictating the sport, there are various examples of expensive parts that have had no beneficial impact for the sport, tubeless tyres and the wheels needed,, karger ignition boxes, blixt carbs,hydraulic valves being some examples 

You're right, but that's where it needs to change. It should be run by the FIM or an Eccleston type character and everyone else has to fall in line for the greater good.

Edited October 23 by Garry1603

[FAST GATER]

Speedway is team sport in name only as Dean says , I have witnessed you get a young lad (in most cases ) who ride will ride anything with an engine and two wheels at a training school where you break the ice off the puddles .5yrs later he won't ride if he hasn't got a GP standard bike  the track is not like billard table ,I have seen this so many times .

Rider demands are why we pulled out of sponsoring what was in the end a thankless expensive  pass time .

[THE DEAN MACHINE]

1 hour ago, FAST GATER said:

Speedway is team sport in name only as Dean says , I have witnessed you get a young lad (in most cases ) who ride will ride anything with an engine and two wheels at a training school where you break the ice off the puddles .5yrs later he won't ride if he hasn't got a GP standard bike  the track is not like billard table ,I have seen this so many times .

Rider demands are why we pulled out of sponsoring what was in the end a thankless expensive  pass time .

One thing than infuriates me is when a company sponsors a rider with their products and then the rider sells the products, I see it so many times, it’s not a new thing either, sometimes it may be part of the deal with the riders but a lot of times it’s not 

[FAST GATER]

18 minutes ago, THE DEAN MACHINE said:

One thing than infuriates me is when a company sponsors a rider with their products and then the rider sells the products, I see it so many times, it’s not a new thing either, sometimes it may be part of the deal with the riders but a lot of times it’s not 

We asked nothing our riders except that they do their best in some cases all they had to purchase was their racing attire  , the final straw was when we just bought two brand new jawa four valves and a month later one rider  put his own weslake in our  chassis . He said the Jawas would make good door stops and were no longer competitive the weslakes hadn't been out five minutes ! 

Edited October 23 by FAST GATER

[The White Knight]

40 minutes ago, THE DEAN MACHINE said:

One thing than infuriates me is when a company sponsors a rider with their products and then the rider sells the products, I see it so many times, it’s not a new thing either, sometimes it may be part of the deal with the riders but a lot of times it’s not 

Thank you for the benefit of your experiences Dean. I am nearly 80 years old and I have learn't a hell of a lot just reading this Thread.

I have followed Speedway since 1964.

Again - Many thanks.

[Youhave2minutes]

5 minutes ago, The White Knight said:

Thank you for the benefit of your experiences Dean. I am nearly 80 years old and I have learn't a hell of a lot just reading this Thread.

I have followed Speedway since 1964.

Again - Many thanks.

I echo that and I’m pleased I started the thread to gain some knowledge