Topic: jetting after a bore

[Techedtyler]

So I've made some intake and exhaust mods on my K5 750 and of course I need to make some carb jetting adjustments. My bike is also bored for one piston size over stock. Will boring one size over make a huge difference when selecting jets?

I've decided to start with #128 mains and #42 slow jets

Does anybody have experience with jetting after boring?

[SONIC]

The bore wont matter as much as the intake and exhaust so jet away

[Red Good]

No it should not , I would ride it and check what the plugs are telling you before I just jumped in with new/different jetting . Unless it is unrideable .

[NewOldSchool]

I recently rebuilt my bike. From my experience and from everything else I've read, switching to 42 slow jets is completely unnecessary unless you have open drag pipes and no air box/ pods.

I have the stock airbox with a K&N filter, rebuilt head and fresh hone, rings, etc. Mac 4 into 1 with the "competition" baffle and a Dyna S ignition.

Jetting:

Slow = 40 (stock)
Air Screws =  1 turn out
Needle = 4th clip from top (1 richer than stock)
Main = 125

Plugs are Denso X24ES-U (factory stock type) and they are perfectly coffee brown.

[Techedtyler]

Newoldschool,

I am running pods and open exhaust so I think the #42 may be a good idea. From what I've read the intake pods have a more drastic effect on jetting needs over exhaust mods. But it sounds like you have a really setup with the ignition system too.
I went with the Pamco electronic ignition and I'm pretty happy with it so far. I'm also running aftermarket coils but I have no idea on their output compared to stock. I really just wanted to be able to change the wires instead of using the old crusty stock wires on old coils forever : )

Only time will tell if my modifications work well together...
I'm waiting for new intake boots and cant wait to try my new carb jetting setup!

I'll report back!

[NewOldSchool]

I'm sure you'll get some flack around here for running pods, but if you like the look and sound of them no worries. Good luck!

[lucky]

Newoldschool,

I am running pods and open exhaust so I think the #42 may be a good idea. From what I've read the intake pods have a more drastic effect on jetting needs over exhaust mods. But it sounds like you have a really setup with the ignition system too.
I went with the Pamco electronic ignition and I'm pretty happy with it so far. I'm also running aftermarket coils but I have no idea on their output compared to stock. I really just wanted to be able to change the wires instead of using the old crusty stock wires on old coils forever : )

Only time will tell if my modifications work well together...
I'm waiting for new intake boots and cant wait to try my new carb jetting setup!

I'll report back!

You are right about the #42 idle jet for pods and open 4 into 1 exhaust.
But do not forget to drop the clip on the needle one notch from stock or it will have a serious hesitation.

I would go with a # 120 main jet.
Try 1 turn open on the mixture.