KZ750 - 4 Jetting for K&N inside AirBox and 4-1

I have just bought but not yet installed a 4 into 1 Vance&Hines exhaust. I already have a K&N filter inside the airbox, replacing the original paper air filter.

I am checking the valves the next weekend, but I want to be sure I won´t get the chrome pipes turn into blue :sick: .

What is you carb jetting recommendation for my setup, assuming the factory jetting is:

Keihin CV34
Pilot / Slow jet: 35 --> fixed - can´t change them
Main Jet: 62
Secondary main jet: 125

Carbs were bought from Wired George 2 years ago, it was plug and play then. Fuel level is perfect.

Thanks for your inputs!

EDIT: sorry, this goes into Carb section. Please Mod change it if you want.

I have a 1980 kz750/4 E1 with the same Keihin CV34 carbs. I have a Mac 4-> 1 exhaust and a no name air filter. I have a 130 secondary main and the other jets are stock. You might find no need to re jet but if you do I would suggest you try the 130.
I got the Keihin jets from z1enterprises.
Good luck

Before installing brand new headers, I sprayed numerous coats of VHT paint inside each one, layered nice and thick.
Used two large cans for the four pipes, spray into the end where the exhaust enters. It runs out the muffler end. And have been very well-pleased with the protection it has provided against any discoloration.

And this includes riding smoking hot for prolonged periods at off and on bumper-to-bumper pace down A1A during Daytona Bike Week.

I thought for sure the pipes would blue, but they didn't. And are still looking fresh and gleaming shiney white chrome after several years riding, including spirited highway cruising, and occasional acceleration exercises.

All the above being with K&N filter in stock air box with perfectly tuned 29 smoothbores, and Vance&Hines exhaust system.

Check out the Z1 in my signature. Pipes look the same today.

Good Fortune!

Thanks for the advice.
Is there any quality difference in buying genuine Keihin jets (6 USD each) or OEM jets... like what Z1 Enterprises sells (less than 2 USD each) ???

undiablo wrote: Thanks for the advice.
Is there any quality difference in buying genuine Keihin jets (6 USD each) or OEM jets... like what Z1 Enterprises sells (less than 2 USD each) ???

I always thought the jets from Z1Enterprises were Keihin. They have the same Keihin parts numbers which are listed on other sites at much higher prices.
If they are not Keihin then all I can say is that I have no complaints about quality. Over the years I have bought quite a few of these jets, both primary and secondary main (never had need for pilots) and never had the slightest issue .

Hi guys!

I have received the 4-1 Vance&Hines exhaust system. I have to say I`m very happy with the craft quality - welding and chrome finish.

I have followed Patton advice and painted the inside of the exhaust with one can of RustOleum 2000ºF high temp spray paint.

However,,,and I know there is always a however.... I have a trouble.

My oil cooler system is:

GPZ750 oil pan
3/8" ID hose (not braided)
HD shovelhead oil thermostat and oil cooler

The thing is the 3 houses are routed between exhaust pipe 2 and 3, but the V&H system has less space there.... what do you guys suggest to do?

I will upload pictures tomorrow.