1976 kz900

Hey guys, I tried searching the forums, but could not really pinpoint the solution. So, a preliminary "THANKS" for all the advice.

Just bought a 1976 Kz900 and the only problem is that once you turn the petcock on, a few seconds later gas starts rushing out of carb #2, through the needle in the bottom of the carb. If the tube is attached then it starts rushing out of the airbox, and all over the bike and floor. Is it an issue with the float?

Also, it seems to be quiet a pain to get the airbox on and off, so while I am down there I am definitely going to rebuild and clean the carbs. However, before I buy the kit, what are the stock jets? Everything is stock on the bike, and its a 1976 900 LTD. The other question is I am living in Park City Utah, which is at about 6500 ft. The surrounding area is around 5000, which I will be riding in a lot, so I dont know if I should use standard jets or not...

And the petcock needs to be replaced, mainly due to convenience because the switch it broken so I have to use a pair of pliers to switch between on and off. It is a dual valve petcock, can I use a single valve? and it doesnt seem to be vacuum driven. Is this correct?


Thanks again!

<Is it an issue with the float?>
The Needle is prolly stuck in the down position due to varnish/gummed up gas.

<it seems to be quiet a pain to get the airbox on and off>
Use a heat gun to warm up the rubbers so you can get them off and put them back.

<what are the stock jets?>
It came with 26mm Carbs.
Depending on which market it was built for it could have any of the following Main Jets.
110, 112.5, 115, 117.5, 120

<can I use a single valve?>
Yes, Get a Pingle brand valve from Jeff Sanders at Z1 Enterprises

<it doesnt seem to be vacuum driven. Is this correct?>
Yes that is correct, you need to turn it on to ride then shut it off when you stop - or else it will overflow the carbs.

After you heat up the carb boots, instead of just trying to pull the carbs out (like the manual says), try folding the boots back onto themselves. This will make it fairly easy to get them out and, more importantly, get them back in after you clean them!

Brian, My KZ900 LTD (76) came with 28mm carbs. Yes you most likley just have a piece of crud in the needle of that carb. I removed the airbox on mine and put pod filters on. Now the carb stack comes off in about 5 minutes. Trust me the carb stack will come off alot. Pretty simple with practice. My carbs had 115's installed when I got it. The kits came with new 115's and 118's. I tried the 118's but ended up back to 115's. Bozeman, Montana is about the same elevation as Park City. My KZ gets about 38 MPG if I ride it like I stole it. I have gotten 45 with the wife on the back and behaving myself at the same time. When the mileage dips to about 32 it's time to service the pod filters.

Awesome! Thanks for the help...

I had a kz650 once, and had pods on her, but i think I am going to keep the airbox this time. 10bucks.. you said you use 115s? What about pilots? do you ever take her to lower elevations (near sea level)? Wondering if I would run into issues if i ran the bike down to sea level for a thousand miles or so? Also, say if i was to move to sea level, what would be the rejetting? up or down? just curious.

Thanks!

i race in calgary and the actual elevation is 3720 ft. but i have never seen it [corrected altitude] because of the lack of humidity and air pressure less then about 5500 ft. so when i race in mission b.c elevation 60 ft i have to go up 2 sizes on my main jets minimium i have 29 smoothbore mikunis in calgary i use 117's and in mission i use 122's it works fine and you will think some body jacked up your frame and switched motors on you the motor feels fantastic, feels like it has an extra 20 horsepower.

If you moved down to sea level youd be better rejetting but I would'nt do it just for a trip. Like what Timebomb said you would be jetting up to go down because there is more and denser air at sea level. 117' or 118's. There is a new pilot jet in the kit but not a selection of them. Take care to flush every and I mean every passage with carb cleaner both directions. A soak would be better but not absolutly neccesary.

hmm.. thanks again! I should have a good start now... Cannot wait for this snow to stop so I can really get riding!
I will keep ya posted on how the elevation affects me. Difference between Salt Lake and Park City is only 30 miles but 2500 ft in elevation.. so daily ride to work at 6500, and 4000 on the off days... hopefully it wont matter too much.

Yeah. My driveway is right at 4000 and Belgrade 10 miles away is 4500. I'll ride if it's clear and at least 25 degrees out. That KZ really runs good in the cold air. Can't ride this week as I'm painting it, but it's snowing every day anyway

it shouldn't be that much of a problem you might have to use the enrichner[choke] a bit more at the lower elevations but it shouldn't be lean enough to hurt anything. you lose around 3% power for every thousand feet of elevation so from sealevel to 6500ft.you would lose almost 20% of your available power.

Well, finally got the carbs off for a nice soak... I didnt note what size the pilots are, but the main jets are 12.5. The carbs are gonna need a nice soak due to all the crap inside of them... but as soon as I get them back on we will see how she runs

Hey guys!

Finally let the carbs soak, which were full of crap, and got them back on the bike. The jets were stock... 112.5 main and 17.5 pilot. All seems to be working well... no overflow.

However, I cannot get her started at all. The battery is low now from try to start her over and over.. but I am thinking ignition. Took off the points cover, and it looks like a spider made a nest in there. I have no idea how but... I am definitely gonna switch from points to Dyna S, and cannot decide whether I am gonna switch the coils out or not. Looked through the forums and from what I have read many prefer stock coils. However, I dont know if they are stock. They are black, and the wires are fitted inside of the coils... You cannot detach the wires. I havent taken them off the bike yet, but I cannot see any markings on the top or outside. Maybe cheap aftermarket?

Kinda bugging me that I cannot get it started.. considering I bought it like 2 weeks ago and it started right up when I got it. However, snow is in the forecast for the next 3 days so.. I should have some time to get it right.