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2 Valve or 4 Valve ?


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Also I've noticed what appears to be a new design of wheel rim & hub used by Martin Vaculik & a few others: the spokes hook in 'lugs' mounted on the rim and the adjustment of spokes for tension & trueness of the wheel is at the hub, as opposed to being the other way around as has always been the case.  Literally don't understand this; same design but different method of assembly there doesn't seem to be any less spokes, tho the spokes themselves do look a little thicker, so can't see any benefit i.e. lightness or strength....

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6 hours ago, martinmauger said:

Also I've noticed what appears to be a new design of wheel rim & hub used by Martin Vaculik & a few others: the spokes hook in 'lugs' mounted on the rim and the adjustment of spokes for tension & trueness of the wheel is at the hub, as opposed to being the other way around as has always been the case.  Literally don't understand this; same design but different method of assembly there doesn't seem to be any less spokes, tho the spokes themselves do look a little thicker, so can't see any benefit i.e. lightness or strength....

It’s for tubeless tyres, spokes are on lugs on rim so no holes like conventional wheels which would let air through, as I said yet another expense added with no benefit to the sport, something I can’t understand about tubeless tyres in speedway is how they stay on the rim, they don’t use tyre locks apparently and in speedway we have all seen how a tyre distorts on the corners I just can’t believe they don’t lose air but apparently they don’t, I got hold of one a couple of weeks back and they have a slightly different inner wall but look identical to a normal tyre, I thought maybe they use a mouse like in motox but they don’t 

Edited by THE DEAN MACHINE
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Is the laydown engine of today massively different to that of say 1995 when they were fairly new? Was the difference so great that it made the upright obsolete quite quickly?

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I remember in the 70's JacK Millen found out that Ivan Mauger had cut away part of  the throttle slide on the Dellorto carb in a certain way ,one of our riders did it but  it made no difference what so ever as far as he was concerned

Edited by FAST GATER
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21 minutes ago, 40-38 said:

Is the laydown engine of today massively different to that of say 1995 when they were fairly new? Was the difference so great that it made the upright obsolete quite quickly?

No they pretty much the same, better quality materials and everyone pretty much went for short stroke over long stroke but I have seen a couple of top riders experimenting with long strokes again, the carburettor was the big difference, the first laydown used upright carbs converted to laydown and this created a problem similar to turbo lag on an 80s turbo car where when you apply acceleration there is a slight gap before power kicks in but by the time the BZ carb came out around 98 that problem had gone 

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Something I have noticed in speedway is when something new comes around you usually find someone had already done it decades before like when gravity fed floatless carbs came out it was like wow but if you know your history wal Phillips has been doing this decades before on japs

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11 minutes ago, FAST GATER said:

I remember in the 70's JacK Millen found out that Ivan Mauger had cut away part of  the throttle slide on the Dellorto carb in a certain way ,one of our riders did it but  it made no difference what so ever as far as he was cocerned . 

Delorto made different slides with different cut always for different power delivery 

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Last year I did a bit of messing about with one of my weslake’s, I made a inlet manifold so I could fit a modern blixt laydown carb on to it,after a bit of messing about with jets I took it to Leicester for a blast and it was really good for 6 laps and then the conrod snapped destroying the engine, engine plates and frame and ignition box 

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12 minutes ago, THE DEAN MACHINE said:

Last year I did a bit of messing about with one of my weslake’s, I made a inlet manifold so I could fit a modern blixt laydown carb on to it,after a bit of messing about with jets I took it to Leicester for a blast and it was really good for 6 laps and then the conrod snapped destroying the engine, engine plates and frame and ignition box 

Very costly exercise

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Just now, Youhave2minutes said:

Are you still moto crossing it nowadays

I still ride veteran speedway stuff,,I raced in the jap championship on Saturday at the iow on a 1958 jap 4a, I’ve never raced motox bike, I’ve rode one and have recently brought a 1980s YZ at auction 

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4 hours ago, THE DEAN MACHINE said:

It’s for tubeless tyres, spokes are on lugs on rim so no holes like conventional wheels which would let air through, as I said yet another expense added with no benefit to the sport, something I can’t understand about tubeless tyres in speedway is how they stay on the rim, they don’t use tyre locks apparently and in speedway we have all seen how a tyre distorts on the corners I just can’t believe they don’t lose air but apparently they don’t, I got hold of one a couple of weeks back and they have a slightly different inner wall but look identical to a normal tyre, I thought maybe they use a mouse like in motox but they don’t 

Thanks for that Deano, makes sense now, 'mystery' solved, as with many things in speedway: all just to do 4 laps in (still) 60 secs or so.....

Edited by martinmauger
spellling
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1 hour ago, THE DEAN MACHINE said:

This is my jap I race currently 

IMG_0313.jpeg

Lovely bike( IMO best looking engine of all time )  always wanted to own and race a Jap powered  bike ,now i suspect I will just buy one and polish it  to look at !

Edited by FAST GATER
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3 hours ago, FAST GATER said:

Lovely bike( IMO best looking engine of all time )  always wanted to own and race a Jap powered  bike ,now i suspect I will just buy one and polish it  to look at !

There is one in the back of my van, it will be at Kempton Park autojumble for sale Saturday 26th Oct., 1930's Rudge Martin J.A.P., it could do with a polish 😁

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What used to be enjoyable about uprights & earlier laydowns was their unreliability. 

Every race was unpredictable in the sense that even if a rider was miles in front they could (and did) breakdown at any point.

Most breakdowns now are just dropped / snapped chains

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