Heres an update on my, carb tuning. Mainly for people searching for carb settings to reference.
Moriwaki wide open exhaust
Uni-Pod filters
Factory stage 3 jet kit.
Racetech springs and emulators (an absolute must)
Ohlins shock on it's way.
Close enough to sea level but I have the japanese alps on the otherside.
Jet Needle Main Jet Pilot Jet fuel screw Spring float
position size size turns mm mm
Original
Front n/a 142 42 1 and 3/8 168 9.1
Rear n/a 138 42 2 and 7/8 168 9.4
40hp Smooth linear Hp curve from red baron dyno
Any amount of chop and WOT will not budge the front wheel off ground
1st
Front 3rd clip 168 42 2 and 1/2 194 9.1 1/4
Rear 3rd clip 162 42 2 and 1/2 195 9.4 1/2-3/4
Throttle sloppy but ok until 4K, bogs down after 5 k badly. Pretty disappointing really and made me feel like I had made a mistake in deciding to Jet. When I cooked the spring it shrunk a bit but I thought it would be o.k. On the next rebuild I re cooked the spring to the right length and properly set the floats with a decent vernier (Very very important)
2nd
Front 3rd clip 168 42 2 and 1/2 203 9 1/4
Rear 3rd clip 162 42 2 and 1/2 203 9 1/2-3/4
Deffinitely better than the last try but alot more work to do.
Good power right through range with WOT
throttle sloppy but ok until 4K bogs down after
bogs down at 5 k badly
3nd
Front 2nd clip 165 42 2 and 1/2 203 9 1/4
Rear 2nd clip 160 42 2 and 1/2 203 9 1/2-3/4
Throttle smooth as original much better power right through range with WOT Still not achieving full potential
Still flat spot from 4.5k but not severe. Definitely wants to be tuned out but is livable. 2nd clip position made a big difference right through the range. Much much much smoother.
4th
Front 2nd clip 158 42 2 and 1/2 203 9 1/4
Rear 2nd clip 155 42 2 and 1/2 203 9 1/2-3/4
Power wheelied
(albeit small) at mid revs WOT, throttle a little less smoother than original but an improvement on the last try.
Further reduced flat spot from 4.5k.
I reckon I'm gonna try 155/152 next and then 152/150. I think one of them should hit the sweet spot and finally let me move on to the rest of the tuning.
Best advice i've got o far is, if you've got an M4 exhaust then you should start at 168/162 however if like me you haven't then your jetting will likely be down towards the low 150's. This is based on all the jetting settings that i've found from other peoples post here and elsewhere on the internet. I don't think it necessarily means less power if your using a smaller jet sizes, I think it's alot more complicated than that, bigger is not necessarily better. Saying that at the moment i'm all about trial and error and don't really no shit about the finer points of the carb specific fluid dynamics involved.
As the bike is right now, It's a massive improvement on the original. I'm holding off going for a proper ride until I get the suspension balanced out with the ohlins hopefully before this weekend.
After that, it's heating up here and I find a nice sticky 40 mile piece of tar macadam up in thems Japanese alps about 30minutes ride from my door.
Let the summer time roll on.
I'll update with any more changes I make for the carbs.
I'd suggest that anyone else with this kind of data should post it in this thread and i'll format some sort of carb tuning database for others venturing into the black art.
I've also got pictures of the carbs internals if anyone would like to host them.
Good luck with your tuning,
Happy Hawking.
Moriwaki wide open exhaust
Uni-Pod filters
Factory stage 3 jet kit.
Racetech springs and emulators (an absolute must)
Ohlins shock on it's way.
Close enough to sea level but I have the japanese alps on the otherside.
Jet Needle Main Jet Pilot Jet fuel screw Spring float
position size size turns mm mm
Original
Front n/a 142 42 1 and 3/8 168 9.1
Rear n/a 138 42 2 and 7/8 168 9.4
40hp Smooth linear Hp curve from red baron dyno
Any amount of chop and WOT will not budge the front wheel off ground
1st
Front 3rd clip 168 42 2 and 1/2 194 9.1 1/4
Rear 3rd clip 162 42 2 and 1/2 195 9.4 1/2-3/4
Throttle sloppy but ok until 4K, bogs down after 5 k badly. Pretty disappointing really and made me feel like I had made a mistake in deciding to Jet. When I cooked the spring it shrunk a bit but I thought it would be o.k. On the next rebuild I re cooked the spring to the right length and properly set the floats with a decent vernier (Very very important)
2nd
Front 3rd clip 168 42 2 and 1/2 203 9 1/4
Rear 3rd clip 162 42 2 and 1/2 203 9 1/2-3/4
Deffinitely better than the last try but alot more work to do.
Good power right through range with WOT
throttle sloppy but ok until 4K bogs down after
bogs down at 5 k badly
3nd
Front 2nd clip 165 42 2 and 1/2 203 9 1/4
Rear 2nd clip 160 42 2 and 1/2 203 9 1/2-3/4
Throttle smooth as original much better power right through range with WOT Still not achieving full potential
Still flat spot from 4.5k but not severe. Definitely wants to be tuned out but is livable. 2nd clip position made a big difference right through the range. Much much much smoother.
4th
Front 2nd clip 158 42 2 and 1/2 203 9 1/4
Rear 2nd clip 155 42 2 and 1/2 203 9 1/2-3/4
Power wheelied

Further reduced flat spot from 4.5k.
I reckon I'm gonna try 155/152 next and then 152/150. I think one of them should hit the sweet spot and finally let me move on to the rest of the tuning.
Best advice i've got o far is, if you've got an M4 exhaust then you should start at 168/162 however if like me you haven't then your jetting will likely be down towards the low 150's. This is based on all the jetting settings that i've found from other peoples post here and elsewhere on the internet. I don't think it necessarily means less power if your using a smaller jet sizes, I think it's alot more complicated than that, bigger is not necessarily better. Saying that at the moment i'm all about trial and error and don't really no shit about the finer points of the carb specific fluid dynamics involved.
As the bike is right now, It's a massive improvement on the original. I'm holding off going for a proper ride until I get the suspension balanced out with the ohlins hopefully before this weekend.
After that, it's heating up here and I find a nice sticky 40 mile piece of tar macadam up in thems Japanese alps about 30minutes ride from my door.
Let the summer time roll on.
I'll update with any more changes I make for the carbs.
I'd suggest that anyone else with this kind of data should post it in this thread and i'll format some sort of carb tuning database for others venturing into the black art.
I've also got pictures of the carbs internals if anyone would like to host them.
Good luck with your tuning,
Happy Hawking.
Comment