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Honda (4 strokes, sorry) were running tiny bore and stroke roller crank engines 125cc fives, 250cc sixes) at 18 - 20,000 rpms back in the 60s. I...

I believe three things were in play with the KZ engines. Firstly was the big end pin diameter, this was like many engines of the 125 size was 20mm (...

1979 Blair Peach killed in London New Zealander Blair Peach died after a clash between police and protesters at an anti-fascism rally in Southall,...

Wobbly and Frits, Not Diameter of Bore ore Bolt Big end, some use 17mm..."quality " of components ;)...foregive me if i dont want to talk about to...

50cc big end pins are Ø15 or Ø16 mm; that is roughly equivalent to 22 mm for a 125cc engine. The RSA had a 24 mm big-end pin, which posed no...

We ran our 26 cc, 28 mm stroke Zenoahs up to 25,000 rpm during testing. That's around 23 m/sec. It was only for a short time on the water, though. ...

Some of the aftermarket expensive 50cc " racing" cranks are very pure in quality...pure shit :(

Congratulations Neil :woohoo:

You are all in trouble now, retired as of this week, parts are being sourced as we speak (read) for the 'ultimate' 100cc twostroke. Haha, I'm full of...

I am surprised as his is the first decent study you have ever posted in the history of this thread out of hundreds of crap you have posted before....

Gents, you are comparing high quality TM race parts developed as a package since ages for a specific race engine to Derbi aftermarket stuff. While...

I have the same question. I do know that things do not scale linearly with engine size, maybe the issue is the big-end bearing inertia? And in a...

Classic 30's

Shell Advance Ultra2 Full Synthetic. We bought several boxes of 1liter bottles. A job lot cheap, end of line runout. We have used lots of it over...

I was brought up using dreadful Suzuki commuter parts. If you revved the crank regularly to 13,000 the life was short, a yearly rebuild was not soon...

I remember when I was at Orbital and we were initially dealing with Mercury, this being prior to the Optimax engine. The engineers were talking about...

The gay son said; "It's ridiculous they make Pride Month in June - most of the gay sex I have, I do it in August." My wife's been a lot more...

Frits, what is the actual problem with the 50cc racers crank reliability. We run the 125 KZ engines to 14800 all day, and the basically same...

1936 Rātana and Labour seal alliance The alliance between the Rātana Church and the Labour Party was cemented at an historic meeting between...

My casually asking about the fuel-oil ratio was a tongue-in-cheek way of saying that there was no oil at all in that fuel. I advise 1:20, same as...

There was a time when health information from a US govt source could be considered authoritative and reliable. Sadly that time has passed. Under...