77 KZ900 Mikuni carb \"caps\"?

I'm making an effort to help out a friend who's helping me work on my 550. He's got a '77 (I'm almost positive, but there is no detail label on the neck) KZ900. (He got it for free, the dirty s.o.b. ) He set all my floats for me, but his carbs (Mikuni's) don't have the outlets coming out of the bottom of the bowls, there's just a cap on each carb. He's always working out of town, so I was going to try to find an answer for him on how we can set these floats.

He's tinkered with just flipping the carbs and physically measuring the floats, but with the age of the bike and the unpredictable nature of older floats he really wants to be able to set them with the fuel level as it just doesn't run right. He even said that if he could just get a spare cap he'd fab up a drain tube to use on them, but none of the shops around here have been able to come up with one. Any help I can get on finding a cap or even a better way to do this would be very greatly appreciated. I've been searching the forums for answers, but I'm not using the right terms or something.

if the "cap" you are talking about takes a 17mm wrench to remove from the float bowl, he probably has mikuni smoothbore carbs...
very desirable carbs for the 900/1000's
good luck finding a spare cap though.

26s use same bottems and tops as smoothbores

wireman, Most 29mm smoothbores, have large drains on the bottom of the bowls to facilitate main jet changes (they are supposed to be racing carbs). VM26s do NOT have these large drains (they require a 17mm wrench to remove). In any case, with a stock VM24/26/28, there is a 6mm drain screw (.075 pitch). To set the service fuel level; that is, use a hose, get a 1/4" vacuum fitting (a straight one) and screw the soft rubber/plastic fitting into the 6mm hole after removing the screw. then put your hose on the end of the fitting. The 1/4" size is just slightly larger than 6mm so it works fine with little leakage for the connection of a hose.

on the red 78a2 ive got posted i took the tops and bowls from the 26s and had them plated then i just bolted them onto the 29 smoothbores later when i bought them.they arent exactly the same but i know they will atleast bolt o there and not leak anyway.thats all i was trying to say since the 29 parts are harder to get.

Post edited by: wireman, at: 2006/06/08 13:27

If the carbs look like the 26's on 76 KZ900 or the 28's on 77-78 but have the jet access cap on the bottom of the float bowl he's got a set of 29mm. smoothbores.

Caps and the rubber o rings are available from Schnitz Racing in Decatur Il. www.schnitz.com

Thanks for all the info, guys, I'm on the right track. What's the best way to tell what carbs they are exactly? Would a picture suffice, or do I need to find some casting numbers or the like?

I'm thinking that at the moment I'm going to try a 1/4" vac fitting and go from there.

Nick - I will attach a pic of the ID Mark location. If you posted pics, that would help as I am still not confident I understand what is going on.

wiredgeorge wrote:

Nick - I will attach a pic of the ID Mark location. If you posted pics, that would help as I am still not confident I understand what is going on.

I'm supposed to go by his place tomorrow, so I'm going to try and snap a few shots while I'm there. Hopefully by this time Sunday I'll be able to shed some extra light on the subject.

After pulling the title we found out it's a '74, not a '77. We tried the 1/4" fitting and found out it's much closer to 3/8", but haven't had time to get a different fitting yet.

And I just realized I can't find my pictures. I'll see what I can come up with later .