Jetting 83 KZ750 h4

So the elevation here in Farmington is about 5400FT an old coworker says instead of needing a tuneup my bike might need different size jets.

For me this is uncharted territory, as far as I know they're still stock.

Think there's any truth in his statement? If so, any recommendations?

A tune up was recommended on here because my bike couldn't make it over 105ish mph with stock gearing. It does about an even hundred now with 14-39.


1983 kz750 H4 LTD.

Yes he is right. Every additional 2000-2500 feet above seal level or where you started from, should also be accompanied by fuel mixture changes.
Is the bike stock... with stock exhaust and stock air cleaner assembly, etc.?

Try one size down on the jets. Fine tune it with the needles. Don't expect more power than you had at lower elevations.
Steve

Everything is stock. How different might I have to go with pods?

whirlwind598 wrote: Everything is stock. How different might I have to go with pods?

OK... i would leave it stock for now and go smaller in the main jet by at least one number and maybe drop the needle (if possible) into the emulsion mixer tube by one notch.
Not so sure I would change the pilot jetting yet unless the needle is not adjustable,
You probably could lean out the idle mixture screw or increase the air if it is an air screw and not actual mixture.
That I would do by idling the engine as slow as it will run smoothly when fully heated up and turn the mixture screws in or out for maximum RPM... just keep closing the throttle/slide down a tiny bit so the carbs are actually running on the idle circuit.
Using pods now might give you a PIA and possibly throw complications in you don't need now.
I'd get it running right for 5500msl with the stock air cleaner setup first ....(It will get even worse [more rich] in the summer time due to additional lowering of the air density at higher temps) .
At a density altitude of 7500ft to 8000ft... (very easy where you and I are, at 5200ft to 5400ft msl in high plains, or Rocky Mountains and any 80-95 degree day) the engine will be very hard pressed to make 70% to 75% of it's sea level power when jetted right... compared to sea level and jetted correctly!!

Ugh I hate the carbs. Lol them rubber hoses going to the air box are a nightmare to put back on haha.

You can soften them up to be as soft as new:

v4musclebike.com/forums/showthread.php?t=13477

Yeah, Bossie runs like a dog at my daughter's house and that's at 4500'.
Steve

Who was that directed at kawi?

You'll hijack any thread to continue your attacks.
Steve

[Two subject posts moved to Poser topic in Engine forum]