Kreidlers like to stay stock, but a few things can help on the hills.
The first mod - Removing the baffle in the exhaust pipe.
- The end-cap unbolts, a 10 or 12mm, hit it with carb cleaner, and pull it out.
- Drilling a little to weaken it helps if it is stuck.
- It adds a crackly-crack-crack when you let off or hang at like 1/3 throttle. Sounds cool
- Adds 1-3 mph. Improves acccel in your head only.
(If you have a Batavus, the 30mph pipe will bolt on nicely to a Kreidler. It seems to add acceleration and 2-3 mph.)
Second mod - Take off the airbox and using panty-hose as a filter.
This caused my bike to actually hit 41 max downhill with two people, 36-38 down grade flats, and 27-33 sustained on up and down roads. This is with a 64 jet-12mm bing. A 68 improves accel, but limits top speed. I need to try a 66, that might be the trick.
Third mod - Second gear clutch spring mod---coming soon with pics
This mod involves two people and patience.
Remove second gear clutch, disassemble - don't lose your chin, and removing with a belt sander 5-13 or 17 coils of the single spring-it only has one.
What this mod does, is cause a lag until the second gear hits-shifts and lets the motor rev up past 1/4 throtttle before shifting.
Stock is 9-11
I got mine to 13 by taking 5 off.
I am shooting for 17-19 shift-downshift to help keep the revs up on the hills.
CAUTION -- It is very dangerous and requires two people for reassembly because the sping is so much tighter.
Fourth mod - Carb upgrade to 14mm
This needs a new body and intake
I have not yet got the carb or intake, but you can reuse the top part of the carb. I'm thinking the 68 jet would work in the 14mm.
Tested 14mm bing (bored stock intake, no air filter) along with biturbo pipe on stock header. 68 jet runs extremely lean. Ordering 70's range jets, will post results after testing.