Re: Largest size for an exhaust 0.71 bore or?

Probably Fred /
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1960s books written by Bell, Graham and others are great info but it’s info is mostly for larger displacement manual shift race bikes that can take high rpm narrow power bands,

It wasn’t written for feeble one speed thin case e50s that are very hard on the clutch, bell, main gear and has crank walk/flex with hi power at hi rpm, narrow powerbands

I wouldn’t wanna make the powerband possibly more narrow or higher rpm to get more power by increasing exhaust size and possibly snagging a ring doing so,

I’d rather have less max HP and a more tractable powerband if the bike is going to have any street use and reliability so I would say leave it where it is at 55

You could actually go pretty fast with better speed control with a lower rpm broad powerband e50,

Stock bottom end and crank, Unported 64cc kitted e50maxi with 15mm bing (90jet) and trick reed plate that makes good power but mostly from 5,000 RPM to a bit over 9,500 rpm,

It cost around 435$ USD to build (not counting the bike) in 2006-2007

And it still runs great years later with routine ring changes every 3-5k mi, piston with ring changes at 8k-10k mi, head temps are cool never goes over 330f, bottom end has over 23k mi on it and has never been rebuilt,

I rode it twice this week and it still put a smile on my face!

Stock clutch is tuned for around 5-5,500 rpm so any speed you’re at : 10, 20, 30, or 40 mph when you twist the throttle it pulls with no lag to 55-57mph making it great for late breaking into corners and blasting out of them and clutch slipping just perfect for hills,

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