Help with jetting a 77 kz400 please.

teddpage said:
Emgo pods...sure. But a Uni-Filter...doubtful.
Click to expand...
anytime you have a capped off restrictive screen clamped right on the carb you are not allowing the air to run in a continuous fluid column, it has to make a turn and is too turbulent to be effective
with those silly little pods it is the worst case, you couldn't really make it any worse if you fucking tried
you are asking the air to break up into little tiny streams (restriction) then it has to make a turn right away and it is not a homogeneous fluid column ....not efficient at all or able to react properly to the pulses of the intake port..
now large LONG unis or large LONG pods will be better, best case with an internal velocity type stack, but still not as good as a longer smooth tube to straighten the air and allow it to be fluid.and the airbox adds resonance as well and is a big part of the picture for flexability of the power.
some hi spec engines use variable length velocity stacks that are movable by servo motors to the resonance of tune of the intake
but you will never :) never :) never :) see any engineer or tuner that knows his salt allow you to clamp a device onto the intake like a little cute "cool" looking POD
it is just so fucking hilarious every time i see it ....
 
Hmmm, ???? I'll look into this further. The air coming in from a pod filter seems like it'd be a straight shot, and turbulent? Maybe, but again, when performance is what most guys are after when building these, there has to be something to the fact that they are on so many bikes? I'm not saying I don't believe you but I am going to look into it.
 
xb33bsa said:
anytime you have a capped off restrictive screen clamped right on the carb you are not allowing the air to run in a continuous fluid column, it has to make a turn and is too turbulent to be effective
with those silly little pods it is the worst case, you couldn't really make it any worse if you fucking tried
you are asking the air to break up into little tiny streams (restriction) then it has to make a turn right away and it is not a homogeneous fluid column ....not efficient at all or able to react properly to the pulses of the intake port..
now large LONG unis or large LONG pods will be better, best case with an internal velocity type stack, but still not as good as a longer smooth tube to straighten the air and allow it to be fluid.and the airbox adds resonance as well and is a big part of the picture for flexability of the power.
some hi spec engines use variable length velocity stacks that are movable by servo motors to the resonance of tune of the intake
but you will never :) never :) never :) see any engineer or tuner that knows his salt allow you to clamp a device onto the intake like a little cute "cool" looking POD
it is just so fucking hilarious every time i see it ....
Click to expand...

My K&N's and Uni's are not as restrictive as those cheap emgo units. Turns and turbulence?
How about short turn radius? Tumble and swirl? Resonance? Is there enough volume in an air
box to catch the wave in a different spot to make a relevant difference? Does a longer velocity
stack restrict flow?
 
Jchaplin, I don't know if it can help you or not, or if your thinking about new carbs, but for my 74 kz400, I got new intake boots, VM30 mikunis, and k&N pod filters put on this summer. My carbs and boots were both shot, so I had to get new ones. It took a while to get the jetting right, but the bike runs great now, the little 400 actually has alot more get up and go than I thought it would.
 
thovda said:
Jchaplin, I don't know if it can help you or not, or if your thinking about new carbs, but for my 74 kz400, I got new intake boots, VM30 mikunis, and k&N pod filters put on this summer. My carbs and boots were both shot, so I had to get new ones. It took a while to get the jetting right, but the bike runs great now, the little 400 actually has alot more get up and go than I thought it would.
Click to expand...

That sounds good to me.
 
Going Mikuni VM30, K&N pods, new ignition/coils, spark booster, velocity stacks and whatever else it needs.
 
Have fun tuning those primary type needle jets, which are designed (primarily)for two strokes. You get to chose if you want midrange rich or top end lean. :)
 
mlinder said:
Also, I'm SURE the slide piston cutaway will be PERFECT!
Click to expand...

I'm SURE the original poster will be chiming in to thank you for all you helpful suggestions
to guide them in the right direction. 8)


.
 
Nebr_Rex said:
I'm SURE the original poster will be chiming in to thank you for all you helpful suggestions
to guide them in the right direction. 8)


.
Click to expand...

I have a bunch of shit I wrote down for vm30's on a cb350... I went through 5 different bleed-type needle-jet sizes, 6 different jet-needle size and profiles, 2 slide cutaways, 5 or 6 air-jets, more than a few main-jets and idle-jets, etc. until I got them right.

I wish I could find that piece of paper...

I hear CX man has that down pretty well though.

The OP should prolly contact him.
 
Good idea, thank you for your response. Maybe this type of information
could be posted as a sticky somewhere.


.
 
Nebr_Rex said:
Good idea, thank you for your response. Maybe this type of information
could be posted as a sticky somewhere.


.
Click to expand...

Are you being facetious? Is it already stickied somewhere?
 
I meant to say I like to think outside the box. To go against the
status quo. To skin the cat a different way. If any disparaging
remark was incurred in my last post I apologize, because it was
directed at myself.


.
 
Nebr_Rex said:
I meant to say I like to think outside the box. To go against the
status quo. To skin the cat a different way. If any disparaging
remark was incurred in my last post I apologize, because it was
directed at myself.


.
Click to expand...


No no. I was just saying that I respect your build. skills and ingenuity. There was nothing that could be misconstrued as a slight in your posts.
 
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