VM33 smootbores

Post edited by: modprod, at: 2007/11/21 22:30

modprod wrote:

mark1122 wrote:

i had my bike out last week. the temp was 7*c.it still runs as good as it did in august.all i can say for sure is they have been good to me.

mark1135cc
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I when out on the back roads for my 1st ever test launch today. i came back puzzled. If i dump the clutch she stalls ? even at 8500 rpm. The front wheel would come up an inch and it would stall every time.i had too slip the clutch to get going. i know your suposed to slip the clutch but it shouldnt stall. Whats up with that?? the roads are cold and the tire didnt seem to be braking loose either ?? ive heard if u dont have enough spark u can blow out the flame ,but i have a new Dyna 2000 and 2.2 coils.?? 155 psi compression. could this be rich or lean ?plug color looks good .anyone have any ideas? same bike as sig bellow.
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76KZ900.1135cc 10.5:1 Wiseco's,k410 cams,1.5mm.over intakes,Heavy springs,shims under buckets,ported,VM33mm.smoothbores,Dyna 2000,2.2ohm coils,Kerker.Cobourg,Ont.Ca.
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Wow!:sick: ??????????????<br><br>Post edited by: modprod, at: 2007/11/21 16:40

Modprod
2 different rides .2 diff tests 2 diff results. after the launch /stalling issue, i did a lot of talking with others and came to the conclution that it is not the carbs but the fact that i have a close ratio trany and 1st gear is just way too tall, and this is causing the stalling, not the carbs. i have just recieved a stock back cut tranny to try next.i will try the 33's with the new trany and see what happens.


i just hope we are all learning through this thread ,what carbs work well on the z's and what there caractoristics are . from this ,others can make there choise easier.from what ive seen here and experianced,there is no reason to be afraid of vm33's. just be aware of there personality,just like all the others ,there are pros and cons.B)lets Keep learning.

Well said Mark

To each, their own. My experiences with all of those carbs, stock 26 - 28 / Mik 29 - 33 has been very different.

Never seen a set of 29's that only "mildly" improved performance over stock 26 -28's. Just the opposite. The 29 smoothbore equipped bikes always ran well away from the stock carbs bikes. Never had any other result.



wiredgeorge wrote:

As far as tuning a GS1100 vs a KZ1100, I know that if BOTH USE THE SAME BS34 carbs (such as those off a KZ1100), the identical jetting will yeild pretty much identical results. The same main jet is needed to be able to pull redline on either bike if pods are used. I think that as far as main jets go, there is some ability to guess what is a good number for either a GS1100 or KZ1100 but as far as pilot jets, not really as Suzuki does the internals on a BS34 differently than Kaw does but main jets will be about the same. Suz tends to use puny main jets in all its larger bikes from the GS750 to the GS1100 for some reason. Kaw likes a bit richer jetting. Dunno what the thinking is.

I can belive you've seen such results. The point is though, that each motor has to be addressed for it's current health condition and setup.

SIDE NOTE: Purpose of thread is to discuss tuning VM33s. .<br><br>Post edited by: wiredgeorge, at: 2007/11/21 16:55

Mark's got the richest jetting I've ever seen in 33's but if he's happy with the results and the bike performs well...Well, what can be said.

Personally, I think tuning 33's is like trying to "duct tape the titanic" but when it comes to not having any money for a good set of carbs, many people will scarf up those discarded 33's for a bargain basement price and forge on....[Mark..that's not a dig at you buddy]. Keep trying and keep learning.

I posted the factory recommended jetting for the KZ1000/1100 a few posts ago. In all the factory shows different setups for the following bikes. Honda CB900/1100, KZ1000/1100, GS1000/1100, Yamaha XS1100, ZX900, ZX1000 Ninjas. This means that the draw characteristics of each of these groups of bikes must be different. The Main Jets range from 125-135, air jets from .6-1.2 pilots from 17.5-30 and so forth. Also since the Honda 900/1100 has the same setup recommendations, tells me that "SIZE DONT MATTER" (much)(for you macho guys) but it's what you can do with it.:lol: :whistle: When I do my final setup I plan not to deviate more than 1-2 sizes out of this range. I do however believe that porting might have the most to do with it. Small things such as runner length , shape, size. Also the Bore to stroke ratio of the engine would have a lot to do with it. A small bore will always accelerate air faster than a big bore. A long stroke will smooth out the vacuum impulses better and so on. All of these factors will play a big difference in tuning these carbs. Since all of us due different modifications to different degrees, every engine should and will react differently. I think that a little bit of common sense here can go a long way. I 100% believe that as long as only one adjustment is done at a time for only the areas affected these carbs can be adjusted as well as any other carb.
Here is a picture of the two sets of carbs which I set up for my GPZ1170 project. I must say that even though the BS34 are "rated" larger to the VM33, There is no comparrison in throat size. There is no way that the BS carb could ever deliver as much air as the VM carb.

Post edited by: otakar, at: 2007/11/22 09:12

Post edited by: otakar, at: 2007/11/22 09:25

Post edited by: otakar, at: 2007/11/22 09:34

Here is a frontal view for venturi comparison

otakar, what is the actual diameter of the throat on the vm's. mine measure 34mm.'s on the motor side and the intake bell has been machined. i will post pics when i get them off.
it does seem odd that i hve bigger jetting but they pull harder and smother this way on my bike.i will be trying rs34's next year,so we can add more to this great topic on kz carbs.

modpro, nice pic's on your site bud.I see Larry has 1 of my favorites.

Post edited by: mark1122, at: 2007/11/22 21:51:evil:

Post edited by: mark1122, at: 2007/11/22 21:53

Sorry if I missed it in this thread, but can someone tell me the standard float height setting for the VM33's? I have a Sudco Mikuni Tuning Manual and it tells the spec for nearly every carb except the vm29 and vm33 carbs. Thanks

OK, found it in a couple of other threads. Looks to be 23mm +/- 1mm. I don't know why that isn't listed in the tuning manual. Oh well, thanks anyway.

79MKII wrote:

Sorry if I missed it in this thread, but can someone tell me the standard float height setting for the VM33's? I have a Sudco Mikuni Tuning Manual and it tells the spec for nearly every carb except the vm29 and vm33 carbs. Thanks

OK, found it in a couple of other threads. Looks to be 23mm +/- 1mm. I don't know why that isn't listed in the tuning manual. Oh well, thanks anyway.

Fuel level is the critical item -- not the measured float height.

In a perfect world, equal measured float heights might produce equal correct fuel levels, but it usually doesn't happen in the real world.

Bottom line --- use the clear tube method to assure correct fuel levels inside float bowls (regardless of measured float heights).

Good Fortune!

I agree Patton - that's the ultimate goal - to have a properly set fuel level. Do you know if the 29 and 33 smoothbores use the same bowl plug? The plugs listed on Z1E only say they're for the 29's and they don't have any listed for the 33's. I was thinking I could make a fuel level gauge with an old plug. Or, do you know of any gauges that fit the VM33's?

i just looked up the parts list for each carb at sudco. they have the same part #.
www.sudco.com/Diagrams323728/expvm29.gif

www.sudco.com/Diagrams323728/expvm29.gif

I just looked them up too and they're different. Here's what I got:

VM33 8. Drain Plug VM33/77 002-603

VM29 30. Drain Plug, Float Bowl VM28/253 002-526

I see now - you posted the 29 diagram twice. I think they're different unfortunately. Does Sudco sell to the public? Everything I read on their site seems like they sell to dealers only??