View single post by Esprit2
 Posted: 03-08-2022 09:44 pm
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Esprit2

 

Joined: 05-01-2005
Location: Minneapolis, Minnesota USA
Posts: 575
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 Of the JH OEM spec Dellortos, I'd recommend the later 40E... regradless of how you wish to jet it. Evolution brought improvement, and the 40E is better than the 40 (no suffix) that was used on the earlier, non-emissions JH 907. Both the 40 & 40E are considered "2nd Generation", and still used "Weber Science".

If you don't mind more of an adventure, the 40N is "Third Generation", and re-wrote the book on carbs... ie, "Dellorto Science".

The 40N is for 1.3 to 2.0 Litre 4-cyl engines, so the 907 fits in that group. There is no OEM standard set-up for a 40N on a 907, so you'd be plowing new ground. On the other hand, jetting the 40N from scratch is less complicated than the "2nd Gen", "Weber Science" 40 & 40E carbs. And once set-up, the 40N is about as smooth running and maintenance free as any carb available (no carb is truly maintenance free). They're not the best for a hotrod motor seeking peak power, but would be very good for the J-H owner who is trying to create a milder mannered, easier to drive engine.

Regards,
Tim Engel

Last edited on 03-08-2022 11:44 pm by Esprit2