PORTING...This has got to be the thinnest intake bridge I've ever seen!

[Larry's Shee]

Copied from that Klemm linc:Low RPM “Surging” - When trying to ride a stock H1 at sustained low rpms, the engine often has rpm “surges” even though the throttle position is not being moved. This surging is not caused by a problem with the carbs or jetting. The surging is a result of the inlet ports having a much larger volume than what is needed for the engine design. The stock H1 inlet ports (at the piston skirt) are the area equivalent of a 34mm diameter …. While the carbs are only 28mm. By reducing the inlet tract volume, the H1 has much cleaner low speed carburetion, as well as the complete elimination of the annoying low-speed surging. We used two different means of inlet tract volume reduction, and both completely eliminated the surging while having “no” loss of high rpm power

Interesting

 

[best]

Copied from that Klemm linc <SOME SNIPPED> By reducing the inlet tract volume, the H1 has much cleaner low speed carburetion, as well as the complete elimination of the annoying low-speed surging. We used two different means of inlet tract volume reduction, and both completely eliminated the surging while having “no” loss of high rpm power

Interesting

Very similar to what Neil and I did with filling the intake reedbox with epoxy and KTM does with its reed stuffers.
There is nothing new under the sun is there?

Steve

 

[Racer51]

I think it 's the idea of the man who invented the thong he only had a little money and some material and made doo with what he had to make something someone will love to put one once and keep it off the rest of the night.
knowing it's on the last bore makes me think he eather went through pistons or got bored enough to try porting since it was on the last bore to begin with.