Two Stroke, Motorcycles.

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Dirk

If 6 Was 9
Location
Watchet
Not being much of a mechanic Dirk I loved 2 strokes as decoking the head was so easy. Unlike my current BMW GS1200.

Why would you need to decoke your BMW?
 
....did the first year of my apprenticeship at an engineering college in Henley, and most of the guys
there had AP50's and FS1E's etc. I waited until I was 17 to get my first bike, and
thought I'd bypass mopeds and get a 'proper' bike, so got a Honda CD175 (blue) - built like a tank
and handled like one it must be said. Anyways, it was secondhand and in good nick, but exhaust
was rotten, so needed a new one. From Honda cost an arm and a leg, so got a pattern 'mega' pipe
instead - loud as f**k. I was consigned as the tail-runner in any group rides we did, the noise was too
deafening for anyone at the rear, and to this day I can still remember that awful 2-stroke smell filling
my nostrils and lungs from the gaggle of oil burners up ahead!

Happy days looking back - but never was a 2-stroke fan...........xx(
 

flatflr

Guru
Location
Just over here
Spent a fair bit of my free time in the early 90s as a mechanic for a mate who raced two strokes.

Krauser 80 (30 bhp and 120 mph from 80cc)

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Honda RS125 (43 bhp and 140 mph)

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and as my own ride I had a KR1S (totally bonkers)

2206833_orig.jpg
 

Dirk

If 6 Was 9
Location
Watchet
I used to build motors for some of the lads who were using CR80 motors in RS125 chassis being run in the 80cc Club. Best result was one of my engines finishing 2nd in the 1997 national championship.
Great fun!
 

Drago

Legendary Member
The lead was added to fuel of old to raise octane level, and thus increase the amount by which the mixture could be compressed without unwanted detonation. The lubricating and cushioning properties we're a happy accident, undiscovered for some decades after lead started going in there. Of course, once discovered the engine manufacturers started to exploit this property.

Fortunately, with no valvetrain and with relatively low cylinder compression the lead is utterly redundant in fuel burned in a two stroke.
 

flatflr

Guru
Location
Just over here
I used to build motors for some of the lads who were using CR80 motors in RS125 chassis being run in the 80cc Club. Best result was one of my engines finishing 2nd in the 1997 national championship.
Great fun!

Saw a few of those around the 80 club scene.

We won the ACU clubmans championship back in 93, then moved up to a TZ250 (in a custom Spondon frame) which was stolen together with the van:sad:

Ended up going back to the RS125 with a RS250 barrel giving us a power valve which we used for wet races, changing wheels and barrel when it started raining before a race could be a bit fraught.
 

flatflr

Guru
Location
Just over here
The lead was added to fuel of old to raise octane level, and thus increase the amount by which the mixture could be compressed without unwanted detonation. The lubricating and cushioning properties we're a happy accident, undiscovered for some decades after lead started going in there. Of course, once discovered the engine manufacturers started to exploit this property.

Fortunately, with no valvetrain and with relatively low cylinder compression the lead is utterly redundant in fuel burned in a two stroke.

The guy who came up with the idea of using lead in petrol was the same guy who came up with the idea of using CFCs in fridges!!!
 

Dirk

If 6 Was 9
Location
Watchet
I remember Jason Absalom racing in the 90s.
I finished 5th in the British Clubman's championship in 91 or 92, can't remember now LOL, when I was racing sidecars. Yamaha TZ powered, of course.:okay:
 

Dirk

If 6 Was 9
Location
Watchet
You might remember a mate of mine ? Geoff Rushbrook. Maybe he'd packed up racing by then.
The name certainly rings a bell, but I can't remember racing against him. Did he have a passenger named Leach, or something like? I think I was probably a few years after him.
 
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