1979 KZ400B2 Carb question

Hello, I am sure this has been addressed but I could not find any info (even on google) about how to properly tune my carbs for sea level. I am sure the stock jets 90/70 are in it now. I am a little new when it comes to motorcycle carbs.
Any recommendations?

Why do you think they are not tuned properly?

Bike is having issues running, rather idling while hot. While its cold it will run WITHOUT choke at 1500+rpm and then after riding will drop below 800 and stall out when stopped. Its even stalled out a couple of time while moving in neutral. I have yet to check the valve lash or look at a plug though. I did install the electronic ignition and has straight through shorty mufflers with headers wrapped. Stock airbox is still installed but going to be installing pods. I have a feeling it needs to be re-jetted. Carbs have been thoroughly cleaned and inspected during restro. Funny thing is, since I installed the electro ignition, the choke no longer makes any difference while cold. If anything it just chokes it out.

The addition of straight through mufflers will likely require some jetting changes. The addition of pod filters will likely require years of therapy. If you insist on going that route, please carefully preserve the air box and its hardware and attachments, they are nearly worth their weight in gold.

Here is a workable solution for the anti-airbox crowd
kzrider.com/forum/3-carburetor/587526-kz...ngle-carb-conversion

I have thought about doing the 2-1 conversion but hesitant from hearing horror stories about it. Also thanks for the info on the pods, maybe I should just keep the stock box.
Going to be working on the bike tomorrow and see if I can get it running good. Hopefully my local CycleGear will have some jets.

Cycle Gear won't have the jets you need, This is where I get the ones for my 76 D3
www.power-barn.com/
They run like a sewing machine stock.
Good Luck

If you put pods on the stock CV type carbs plan on spending a lot of time and $$ on jetting and probably more than a few hours in a psychiatrist office. :laugh: :laugh: :laugh: Ed

I have a 78 kz400 with cheapo pods and a 2-1 exhaust with baffle removed. In that one I am running 95 mains and I forget what the float height is set at (2mm below top of bowl?) but it played a big part in getting the full range of power. Had some quick-idle to WOT bog but doing a vacuum sync and getting the mixture screws set right cleared it up. I have a set of 92 mains that would probably work even better since it's just a hair rich according to the plug chop, but it runs fine so I'll just leave it.

I have another 78kz400 with pods and a 2-2 exhaust and I think I have the stock 90 mains and it runs great all day long, however, that bike actually came with a 2-1 exhaust originally so it might have canceled out.

I also just finished a 440 hardtail chop with the stock cv carbs, pods and extended 1.5" pipes that I put slip-in baffles in it (although I bet those provide more back pressure than the original 2-1). Haven't touched the jetting on that one yet but it runs great so far, haven't had it to WOT though...

Anyways, yeah one of the bikes was a bit of a PITA to dial in, but it is worth taking the pods and carbs off 20x than trying to get the carbs out from the stock airbox setup just one time, man that sucks. I think I cussed more messing with the old setup than dialing the podded carbs in.

One thing I tried that I still have on one bike is I put some black socks rolled over twice over the cheap pods. I can't tell you if that helped or not, but I'm afraid to take them off the bike is running so well...make fun of me all you want!

Can't say anything about the 2-1 setup but I'm tempted to try one out just for giggles when the pinhole in one of my carb diaphragms finally gives out, there's a thread on the kz400 forum about who is running what carb and setup and how they jet it and how it is running for them, but as far as I know there is no magical setup.