Progression of dirt bikes, which were the pioneers?

[LWC82PE]

Husky is 83/84 510cc Well thats what they called them, true capacity was probably less, remember the 610 was no where near 600CC

First production dirt bike with USD would be the 1984 KTM's (possibly ATK too??) but before that you had a lot of small bikes from europe and england with primative USD forks eg BSA bantam

[Nathan S]

First production dirt bike with USD would be the 1984 KTM's (possibly ATK too??) but before that you had a lot of small bikes from europe and england with primative USD forks eg BSA bantam

And Honda Z50s!

Think the 83/84 KTMs had USDs as an option only - they were production in 1986+.
They became mainstream in 1989, when they were fitted to all of the adult MXers, except for the CR125 & RM125.

[LWC82PE]

Yeah z50's too

83 KTM's ever had USD as they had disc brake and Marzocchi Forks. I also dont think they were exactly an option either. The original inventer said the the 4054 was only on the 1984 MX500 models  (i reckon ive seen them on 84 250/125's though) but i think some countries didnt get the 4054's as in the parts book if shows Marzocchis too. Deliveries of 4054's to KTM started in the end of 1983. So i would have said that they were definitely on production 1984 KTM's.

[David Lahey]

In 1995 Honda released their current trials bike (called Montesa 4RT) with EFI. A programmable throttle body was a popular option and was standard on the Repsol replica version. The motor was developed from the CRF250.
In 1974 Yamaha supplied mechanical fuel injection for their factory-supported trials riders including top level Aussie rider Peter Paice. It was not introduced on any production bikes.

[TooFastTim]

Gas gas have run fuel injection for over 5 years now, does anyone know the first year that atk trialed it?

Gasser introduced FI in 2002. ATK were using it in the mid-90's.

In 1995 Honda released their current trials bike (called Montesa 4RT) with EFI.

2005 Dave. 1995 was the year that Colomer won the W/C.

[David Lahey]

Gas gas have run fuel injection for over 5 years now, does anyone know the first year that atk trialed it?

Gasser introduced FI in 2002. ATK were using it in the mid-90's.

In 1995 Honda released their current trials bike (called Montesa 4RT) with EFI.

2005 Dave. 1995 was the year that Colomer won the W/C.

Thanks Tim - brain affected by painkillers

[Nathan S]

Boxed swing arm pivot - late 1980s, Hondah, I  think.

Long swing arms and big diameter forks (compared to pre-75 bikes which were all pretty much using 35mm forks and short swing arms) are both important ingredients in modern bikes, but there's no Eureka moment - they grew over a number of years as increasing suspension travel made them valuable.

[Boyracer]

Its kinda funny how black seats are cool again after everyone went blue or color coded, is that a black frame on the new YZ80?

[Mike52]

Could that Husky be a 84 model ?
Sweet bike that.
Later 4/S husky was the first production engine to use a cup full of oil in that 2/S -> 4/S thingy.
Brilliant. The lightest 4/S ever made.

[PEZBerq]

85 model I think Mike. The 84 used a plastic tank that looks more like the 83 shape. Twin shocks were still being used in 85.