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Old 10-20-2012, 06:31 PM   #6
Kai Ju
Beastly Adventurer
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Joined: Jul 2009
Location: So Cal
Oddometer: 1,910
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For this to be useful, posters need to add Model/Year/level of modifications such as exhaust and intake/airbox. Cylinder head work, cam, compression etc.

So here goes:

1977 R100/7 with stock replica mufflers ( EMGO), '79 starter cover with the cast aluminum intake opening, stock clamshell airbox with stock paper filter and the stock elbows going into the bellmouth of the carbs and sealed. Stock engine with 42,000 miles and 150 lbs compression.


Main Jet 210
Pilot Jet 30
Airscrew 1 2/3 turns from seated
Needle Jet 166 P-8
Jet Needle 6DH3
Slide Cut Away 2
Main Air Jet 0.5
Needle Valve Ass'y 3.3

I started with a 200 Main Jet but power would increase when I backed the throttle off some. May go to 220 to see what happens.
Pilot jet was a 17.5 which was recommended by a friend of a friend. Totally inadequate, engine wouldn't run/idle unless the airscrew was seated all the way. Worked my way up to 25s and was pretty happy except slow to warm up. Went to 30s a couple of days ago. No change in warm up but off idle transition at speed,i.e accelerating from steady state throttle, feels better.
In mixed riding I used to get 35 mpg with the Bings, now I get right at 40 mpg. The engine pulls really clean through the rev range and, if I use common sense, giving it a handful results in clean acceleration. No hole to climb out of, just acceleration.
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