KZ900 Carb Re-Jet and Tuning

Still having issues...
So I flooded the carbs the other night by leaving the petcock on overnight.
Got everything apart and dried overnight the next day.
I put new sparkplugs in because I wasn't getting a great spark on the originals.
With new sparkplugs and dry cylinders I started it up and it idled at 900RPM. Great news!
Let it idle for about 5 minutes and shut it down.
Started back up and the idle is back up to 2000rpm. No other changes.
Pulled the new plugs and they were completely black, fouled, too rich?!
Air screws are at 1 1/2 out at this point on all 4 carbs.
Got on the throttle a bit in neutral, hanging idle...generally considered a lean condition yes?
Went for about a 5 mile ride, no popping on decel, black soot in the exhaust pipe, but still high RPM.

I got the stock airbox in the mail today. Will be installing that and possible jetting down a size to 117.5 pilot.
Any ideas on the following questions:
1. Idle at 900rpm with brand new sparkplugs, plugs show rich condition after 5 minutes, idle then jumps to 2000rpm - Could the change be due to the new plugs having a good spark and the increased RPM be due to the plugs getting fouled leading to weaker spark?
2. High idle is generally considered a lean condition yes? Why would I have black plugs and an idle that will not dip below 2000rpm?

Nebr_Rex wrote: [I have not bought a head for a while.
Compare price against ebay. Local prices should be a little less.
You will need one with new valve stem seals and valves that seal.
You will also need to set valve lash/shim the head. The valve train
on your head can be transferred to another head.


.

Ok...next on the list. I just talked with someone about repairing or replacing my cylinder head due to the broken exhaust mounts and the issue with the spark plug hole. He agreed that it would be better to replace than attempt to repair. He does not however have any z1 heads. He said that a kz900 and a kz1000 head would both be an acceptable swap. He said the kz900 is a direct swap with the z1b and that the kz1000 would just have bigger exhaust bolts (8mm instead of 6mm). He has several kz1000 heads in his shop to be sold however he said the kz1000 is more expensive because of the 8mm bolts. He quoted me $400 for a kz1000 head. Ebay is all over the place with pricing. Anyone know of other outlets to get a new head?

You might try KZ Market on face book. It is a closed group that one has to join but it's pretty easy. I've seen about every thing for sale there except a decent period correct sissy bar. Tim

Thanks for the heads up. Will try.

Will be attempting to fit my new stock airbox on the bike tomorrow. I read it can be a bitch to get them on the carbs. One positive of the pods is that I can pull the pods and carbs off the bike in about 2-3 minutes. Maybe that is more an indicator that I've been having to pull them too often haha.

Also - I am able to get my hands on a float height guage, is that an acceptable way to measure versus the clear tube method?

Yes the runners are hard to get on the carb but. I smear a very light coat of Vaseline on the inside of the runner. I get them close then use a 90 degree pick to move the runner onto the carb. The pick goes between the carb and the runner rubber and gently massage into place. Be careful not to poke anything.

I know of no other method to measure float heights other than the clear tube.

Air filter doesn't want to fit in its housing

Made the filter fit. Now having trouble with the pieces I got in the mail. It doesn't look like an airbox will fit between the battery and carbs.
Do I have to use the short attachments or can I connect the airbox directly to the carbs?
If I force the rubber from the air box onto the connector it doesn't fit right.

Also-
Where does the breather tube go?

Yes? No?
I do not have instructions and cannot find an install on YouTube

You have a 76 KZ900 bike. The filter body you are try to fit in is for 73 Z1 and 74-75 Z1A and B models.
Your battery holder is different mounted

My Z1B battery and filter body setup



Michael

Scirocco wrote: You have a 76 KZ900 bike. The filter body you are try to fit in is for 73 Z1 and 74-75 Z1A and B models.
Your battery holder is different mounted

My Z1B battery and filter body setup

Michael

Ya....I got so hung up on it being a 75 engine and carbs that I forget the frame is a 76.
From what I've heard, the 76 stock air boxes are hard to come by right? If I return this and cannot find the stock 76 airbox it looks like I'll be trading this in for K&N pods.

K&N Pods will be delivered today (cannot get my hands on a kz900 air box) and I want to do clear tube method.
Most of the videos I see show the clear tube hooked to the drain, and the drain is opened using an allen wrench or something. However my carbs only have a drain plug. In order to test it seems I will have to hook up the clear tube, fill with fuel, test, then drain, replace with drain screw and refill. It seems that I will have to do this four times, unless I want to cut 4 pieces of tube and do it all together. Does anyone have any other recommendations? I'd rather not do it 4 times, and I had to use a razor to cut the tube to fit in my drain hole. Thanks,