Can't decide what carbs to use

i realize they put vac secondarie carbs on street driven cars which is much more drivable than mechanical,but putting a quadrajet capable of flowing 900cfm on a 283 chevy still dont work as good as a small 500cfm carb! :woohoo: a motor can only use as much air/fuel as it can suck into its cylinders at a given speed. try pulling a line of people that are 5' tall and weighs 400 lbs each through a 32"door then try pulling a line of people who are 6' tall and weigh 175lb each through the same door and tell me which one is easier to fill a room with. :laugh:

www.4secondsflat.com/Carb_CFM_Calculator.html i come up with around 65.68ci for a 1075 motor ill let one of you nasa engineer types figure out the VE and convert the required cfm to mm .i realize its from a car site but filling a cylinder is filling a cylinder basically in my book anyway! :laugh: using the same 65.68ci with 88% VE shifting at 7000rpms(good middle ground i believe anyway)i come up with 117.069 cfm total for all cylinders or 29.267cfm for each,now what is that in mm anyone? sure you could plug 9500 in there for a shift point if youre smoking crack but i dont believe many people shift at 9500 on a regular basis on a 2v streetbike when cruising around town. B)

Via Nads...

"I've never had a set of cv's hesitate whatsoever, unless the airbox was off or jetting wrong.

Ask Larry 'c what happens when the dyno talks on this issue? Only prob is when u whack the throttle, the bike bogs and the front drops down proceeding are two consecutive front rolls."

You started off spewing I don't know shiza by quoting my response, then in the very next post you write about the problem the bogging effect... Somewhat as I wrote, low/mid range performance issue...hmmm, interesting.

Am I a carb expert, hell no, never claimed to be but I did do my research and have found here in KZR and other locations using search and in speaking with others with experience all state the same, stay away from them for a PITA to tune for ideal and desired performance/operations especially in my mild build..

BTW, Larry was one of the mentioned reliable sources regarding the preferred carb based on as I mentioned, riding style and engine/head mods...

Sure if you ride mid to WOT all the time, 34's will perform no doubt but who here truly rides that way more than 80% of your riding time on a street Kawi....

And this would still only truly work out regarding performance if the head porting and valve build is accomplished for the ideal air flow requirement.

If your into drag racing, 28mm would not be the way to go but as mentioned, his question is in regards to a street ride...

Dude, take your meds... :whistle:

nads.com wrote:

Big blocks, funnels, plummers, more money eithers or's and such. Royal nonesuch. Cv carbs out pull, out dyno tune, outsmart, litterly outset vm 28's all day long ev. day. Ask Larry 'c what happens when the dyno talks on this issue? Only prob is when u whack the throttle, the bike bogs and the front drops down proceeding are two consecutive front rolls. Never seen it hap, but been hearing stories. We need a couple of kz myth busters. Couple new ones anyhow.

actually its very simple if you ever compare a rectangular port intake and an oval port head on a bigblock chevy the intake will bolt right on but it will only flow as much air as the port on the head will allow .same reason that you dont port an exhuast port bigger than the inside diameter of the exhuast gasket which is smaller diameter than the header tube,keeps exhuast gas from being sucked back in as easily same affect on the intake port.simple enough?

ok ill use fish instead of bigblock chevys or plumbing termanology for ya! :woohoo: the salmon is the air/fuel mixture trying to get from the 34mm carb bore to 27-28 mm port but its got a big step in its way demonstrated by the water fall! make sense now? :laugh:

:laugh:

edited because it just ain't worth my time.

And now back to our regularly scheduled program...


I've been watching ebay like a hawk for a set of mikuni VM 28's. So far I've noticed a trend to be around $110 to $125 depending on condition. I saw a nice set go for $82 and I just paid all the bills and couldn't pony up the cash. If you can get a set for cheaper go for it. But you might wanna rebuild them. There's another $80 - $140 or so right there. Maybe get a stage 3 jet kit. There's another $95-$112. good luck.

Ford-Truck... PM timebomb33 for he's replied he has a set of 28's that may be just what your looking for... Tim's a good guy with a whole slew of experience in these old machines and carbs...

In any manner you go, just do your re-search first and honestly ask yourself what your expecting in performance based on your engine/head build and your riding style as well. From this, you'll know which model & size you want.

Outside of our wife's/Girl friends miss informing us neanderthal cavemen, bigger is not always better and this does hold true in carb selections...

The best story Larry provided was as follows....
Forget the guys name but goes like this where a small 1045 build, CR 31/33mm and the guys was kicking the crap out of everyone back east... The big blown motors with massive carbs just couldn't figure it out how this little as 1045cc was handing them their ass....

Larry replies wisely, "the guy had this engine, cam selection, head valve/porting and carb selection just so perfectly tuned, that's why!"... Smart man that Larry...

OMR

fordtruck wrote:

I'm getting ready to put a 1075 kit in my 77 KZ1000 and I'm going nuts trying to decide what to do about carbs. I have VM26's on now. Here's a list of mods that will be done:

1075 10.5:1 pistons
Head rebuilt and probably mild port job
V&H megaphone with baffle
Air Pods
Dyna S with green coils

I won't be able to afford smoothbores. I'm torn between BS34's and VM28's. I had planned on running the stock VM26's for a while, but I may be able to squeeze enough money out for a different set. Can someone help me make up my mind? This bike won't be on the strip, I just want a strong street bike.

Thanks

I'd go BS34s and posted why ..Seems everyone has a opinon. If you were Dragging the bike yes some flatties but you asked a simple question.In your quote you said 28s vs Bs34s and quote This bike won't be on the strip, I just want a strong street bike. Merry Christmas Brother..
WoW its Christmas:woohoo:

:laugh: :laugh: :laugh: :laugh: :laugh: :laugh:

You guys! :laugh:

Merry Christmas :laugh:

This guy did say that its a 77 KZ... that means old head.
Even if he does polish it up a bit, it wont flow like the J heads of later models, that had the BS34s'.

If it was a J head, then yes to all the BS34 yay sayers, they would out perform all around. Snappy even like slides.

But it aint! :laugh: :laugh:

I have 79 KZ1000 that only works well with the VM28s.
My 81 KZ1000 has a polished J head (of course), and the 28s' were anemic on it. The BS34s (after like a whole month of tuning) flat out kill my 79.

And then came the pods... :laugh:

Ended up (so far) with the 79 faster with pods, and I'm using a K&N in the air box of the 81.
Which is just almost as fast...

I love pods, and will be going to them on the BS34 soon, which I'm absolutely certain will be faster than my 79 once dialed in.

Its all up to you man!

If you like tinering and tuning, the BS34s will give you the oportunity to swap heads later, and not worry about having to change carbs. If your really not going to do that (like most people), the 28s will be very fast, and fine.

CHEERS!!

:lol:

It doesnt have to be absolutely perfect... You're going to love the #@$% out of it no matter! :laugh:

I should have a set of 28's in the shop. I probably got three sets.

If you want to buy a set i will sell you a set for a hundred bucks and pay the shipping.

I will try and find a set of jets that won't starve the engine.
You will have to do the set up on the floats and what ever else they might need.

If you have the 26mm float bowls you are good to go.

I probably got a set of 34's also with the intake boots. I haven't been through them. They have just been sitting on the shelf.

Just send me a PM.