bs34mm carbs on kz1000

1616river wrote:

ha roy thanks for your help.I shipped the bs34 to oldskool carbs to have them rebuild.I don't know what Main jets should go in.Are the 40/140 big?I had 26mm with 115 but the bike ran hot.

Let us know how they turn out, and how long the wait please. Some places take 4 months or more to get your carbs back...

Got the bs34 on at frist was hard to get started.But when thay got warmed up would start right up.I had the jets that Roy said 40/140 had low rpm hesetate but after 3000 rpm the ran like a raped ape.The guy oldskool carbs was great.Got the carbs back cleaned,painted,jetted new screws.Very nice job and got them back in 8 days.And that was xmas time.

I have these carbs on a GPz1150 and I love them. The trick is not the jets but the needles, and slide modifications if you are using pod filters. I have stock pilots (37.5), main jets are 145. For your engine 130-140 would due fine dependent on the cams you are running and the head-work you have done. If the cams and head are stock than 130 mains are more than enough. The trick are the needles. I had a set of custom needles made and there is not a bit of hesitation and the acceleration is as good or better than I had with a set of smooth-bores. With stock needles I had all kinds of hesitation. What size needles do you have in there now? Wit pod filters you change the vacuum differential curve at the diaphragm. You must accommodate this by modifying the slide. There is some machining and tweaking involved. The pilots they put into yours are WAY too big. This is one of the reasons you get hesitation. You are much to rich at idle. Most places do not even know how they exactly work, let alone how to rebuild them. Anyone can clean a set of Aluminum castings and use a rebuild kit to install new parts (most places don't even do that much) but to set them up for your bike takes someone who knows. The needle is what provides the fuel delivery profile not the jets. The mains are only affective from 85% open to 100% open and the pilots are from about 7%-15% open. everything els is done by the needle. Below 7% is done by the adjustment screw. If you have any questions you can PM me or email me at otto@condormodels.com .

Here is the set of carbs I am using. The BS carbs would not be my choice for the drag strip, but they are my No.1 choice for the street. I get arm pulling performance out of them. Replacing components is very simple. Making the proper adjustments is an art form. There are some here on this web sight that know their business when it comes to adjusting carbs. But there are a LOT of opinions. Just take it slow and use some wisdom and you will get it right. I have about 14 sets of different stiles of carburetors to chose from, but I elected to go with the BS34s at the end.

:woohoo: I am so tird of carbs.You have one thing fix to find out your still not right.Now it is the needles.I am not so sure I made the right choice going with the bs34.

hi i am new to this site and i have a 1981 kz1000 csr m1.u seem to know alot about these bikes can u tell me if i can swap wire wheels to mag thanks jason

That GPz started out life as a CSR, that is exactly what I did. It has a 1979 LTD rear wheel and a 1978 front.
kzrider.com/index.php?option=com_kunena&...w&catid=11&id=169462

The BS34s are great carbs but you have to set them up for your particular bike. Back in high school I remember all the fools that put Holey 850 double pumpers on their stock Chevy 350s and thought that it will make them faster. Somehow I wound up stomping on all of them with my Holey 650 with vacuum secondaries. The BS34 is a fantastic carb you just have to know what you are doing or have it done. You cant just guess at it.