Different carbs on my 73 z1 900

I just bought a 73 z1 900 and am in the process of getting it to run. Problem is, I purchased a carb rebuild kit for it and it is not right. The carbs that I have require a longer air idle screw than what came with the kit, and the kit I bought is specifically for a 73-75. Also the numbers on the jets that are in the kit are not the same as what was in the carbs. The needle jet that was in them had 12.5 stamped into them and the ones in the kit have 13 stamped into them. The kit also came with two of the same jet but they had different numbers as well. One had 17.5 and the other had 20 on it. I may can get by with using some of these parts in the kit, but the gaskets are not the same so I cant use them and will need to buy new ones. I dont believe the guy that I bought the kits from will exchange them for me since I didnt realize this before I bought them. I believe that the PO had put a newer set of carbs on it. Can anyone tell me any problems I may face if I get the right kit for it and use these carbs? Also if anyone has a set of carb bodies for my 73 that need rebuilding I may be interested. I know I am rambling here, sorry. Thanks in advance for anyones help on this. Joe

You don't own a 73 KZ900... they didn't make the KZ900 till 1976. You own a Z1, if indeed you have the year right. The Z1 uses VM28SC carburetors and that is what you bought kits for. Your explanation of the parts indicates the kits will accomodate either a Z1/Z1A or Z1B (they changed the carbs a bit in 75 for the Z1B) and it is obvious you have some other type carb assembly on the bike. It is very likely that almost NONE of the parts in your carb kits will be right for these carburetors you own. You MIGHT be able to use the pilot jets (the #17.5 type). What you are calling a "needle jet" is a main jet and they are stamped 112.5 on the old ones and 113 on the new (they just round up the number for the stamping).

If you decide to do this job yourself, you might want to ident the current carburetors and buy a shop manual as it appears you might have some issues otherwise. Good luck.

jdsmithinc wrote:

I just bought a 73 kz900 and am in the process of getting it to run. Problem is, I purchased a carb rebuild kit for it and it is not right. The carbs that I have require a longer air idle screw than what came with the kit, and the kit I bought is specifically for a 73-75. Also the numbers on the jets that are in the kit are not the same as what was in the carbs. The needle jet that was in them had 12.5 stamped into them and the ones in the kit have 13 stamped into them. The kit also came with two of the same jet but they had different numbers as well. One had 17.5 and the other had 20 on it. I may can get by with using some of these parts in the kit, but the gaskets are not the same so I cant use them and will need to buy new ones. I dont believe the guy that I bought the kits from will exchange them for me since I didnt realize this before I bought them. I believe that the PO had put a newer set of carbs on it. Can anyone tell me any problems I may face if I get the right kit for it and use these carbs? Also if anyone has a set of carb bodies for my 73 that need rebuilding I may be interested. I know I am rambling here, sorry. Thanks in advance for anyones help on this. Joe

I believe that the PO had put a newer set of carbs on it. A pic would help identify the existing carbs. If posting several pics, suggest putting each pic in a separate successive post (just reply to your own post with the next pic, and so on.)

IMO, may be better off with the existing carbs than reverting back to those on the original 1973 Z1.

73 kz900 -- Btw, "Z1" models were 1973, 1974 and 1975, with "KZ900" model beginning in 1976.

Good Luck!

Sorry about the incorrect designation on my bike (feeling a little schooled right now) Wont happen again (tail between legs begging for forgiveness). Here is the bottom side of the carbs in question.

top side

side

other side

frame sticker date of manufacture is 08/73

engine numbers

The bike in question

the other side

So what do you guys think? I really think I just want to buy an original set of carbs for mine, although my bike is far from original.