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Dual VM30s on a KZ440. Anyone done it yet?

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20 Jul 2021 15:29 #852147 by SteveKing84
Dual VM30s on a KZ440. Anyone done it yet? was created by SteveKing84
Been thinking of upgrading my carbs to the dual VM30s put out by Speed Moto.  I've been having a lot of trouble with my carbs, and it seems like that's normal for 440/400 owners with these CV carbs.  Anyone here do the dual VM30 upgrade?  Will the pods fit behind the two side plates when the airbox is removed - ie will they remain hidden and look stock?

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20 Jul 2021 16:31 #852153 by loudhvx
Replied by loudhvx on topic Dual VM30s on a KZ440. Anyone done it yet?
I used the knockoff Chinese VM-30 carbs.

I posted some details in this thread. 
kzrider.com/forum/11-projects/611489-due...00-s?start=36#812179

With very little jetting I was able to ride it.  The project has been sitting dormant since covid etc.  But I hope to get back to jetting it some time not too far in the future.  

I'm pretty sure the side covers would fit, but it certainly won't look stock without the airbox.  The airbox is very visible, normally, so it will be obvious it is missing.

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20 Jul 2021 16:33 #852155 by SteveKing84
Replied by SteveKing84 on topic Dual VM30s on a KZ440. Anyone done it yet?


I'm pretty sure the side covers would fit, but it certainly won't look stock without the airbox.  The airbox is very visible, normally, so it will be obvious it is missing.
 
Any chance the airbox can be modified to fit the pods through it?

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20 Jul 2021 16:37 #852157 by loudhvx
Replied by loudhvx on topic Dual VM30s on a KZ440. Anyone done it yet?


I'm pretty sure the side covers would fit, but it certainly won't look stock without the airbox.  The airbox is very visible, normally, so it will be obvious it is missing.

 
Any chance the airbox can be modified to fit the pods through it?
Probably, but you would be destroying the airbox...carving the holes bigger to accept the pod filters.  It would probably easier to just actually use the airbox and makeshift some radiator hose to connect the airbox to the carbs.  A buddy of mine did that to connect stock carbs to the stock airbox and it worked/looked great.

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20 Jul 2021 17:33 #852164 by Nerdy
Replied by Nerdy on topic Dual VM30s on a KZ440. Anyone done it yet?

I'm pretty sure the side covers would fit, but it certainly won't look stock without the airbox.  The airbox is very visible, normally, so it will be obvious it is missing.
 

Yup. The 440 airbox is this massive thing that takes up a lot of space between the frame spars. It's also a snug fit: removing it was an enormous PITA. I'll probably add some cosmetic panels to hide the battery box and electrics. I haven't decided whether to keep the existing side covers and I'm not a fan of the "empty midsection" look.

I have a set of VM30s for the 440 project, but those will be getting velocity stacks rather than pods. They will have a layer of UNI filter material over the screens inside the stacks so the engine won't be breathing unfiltered air, but if you look at them from the side they will appear to plain old stacks.

1979 KZ400 Gifted to a couple of nephews
1967 Yamaha YCS1 Bonanza
1980 KZ440B
1981 Yamaha XT250H
1981 KZ440 LTD project bike
1981 GPz550
2013 Yamaha FZ6R

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21 Jul 2021 19:52 #852248 by SteveKing84
Replied by SteveKing84 on topic Dual VM30s on a KZ440. Anyone done it yet?


I'm pretty sure the side covers would fit, but it certainly won't look stock without the airbox.  The airbox is very visible, normally, so it will be obvious it is missing.


 
Any chance the airbox can be modified to fit the pods through it?
Probably, but you would be destroying the airbox...carving the holes bigger to accept the pod filters.  It would probably easier to just actually use the airbox and makeshift some radiator hose to connect the airbox to the carbs.  A buddy of mine did that to connect stock carbs to the stock airbox and it worked/looked great.
stock looks clean.  If I can order a “new” box on eBay, I’ve got no qualms about destroying it.

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28 Jul 2021 15:43 #852732 by SteveKing84
Replied by SteveKing84 on topic Dual VM30s on a KZ440. Anyone done it yet?
I did it, pulled the trigger on a dual VM30 setup.  My question is with the petcock or "fuel tap" as kawasaki calls it.  The petcock has a vacuum line that connected to the old carburators, what do I do with this now?  Do I need to replace my petcock with one that has a different setup?

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  • Scirocco
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  • Never change a running system
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28 Jul 2021 16:11 #852734 by Scirocco
Replied by Scirocco on topic Dual VM30s on a KZ440. Anyone done it yet?

I did it, pulled the trigger on a dual VM30 setup.  My question is with the petcock or "fuel tap" as kawasaki calls it.  The petcock has a vacuum line that connected to the old carburators, what do I do with this now?  Do I need to replace my petcock with one that has a different setup?
To get a vaccum tube connected to your petcock you have to add/modify one of your VM30 carbs. Drill a hole, cut a thread and screw in a brass tube..... 

 
 

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28 Jul 2021 16:34 #852738 by SteveKing84
Replied by SteveKing84 on topic Dual VM30s on a KZ440. Anyone done it yet?
Son of a f*cking b*tch.  Just another thing to tackle.  Currently, I would not advise anyone to purchase the dual carb kit from Speed Moto Co at this time.  It came with zero instructions, it did come with a brass barbed "tee", but the tee does not reduce the fuel tank line down to carb size.  It came with a fuel filter, which is nice, but again I have no means of reducing the fuel tank size down to the carb size...unless I use a hose clamp to clamp the oversized fuel line to the tee ( which it also didn't come with ).  I went to 4 hardware stores looking for a 3/16" to 1/4" brass barbed reducer and failed.  It also didn't come with enough hose for to properly get the lines down to proper dump location.  Now I have to drill a carb, tap it, and buy a brass connector.  I'm thoroughly pissed off with this since they called their kit a "big red easy button" during one of the conversations I had with them prior to ordering.  I'm really unsure how they can charge what they do, when they don't provide the necessary things to make the connection...especially since at the bottom of the product page they say: "Q. Why is your kit more than that other guys ?  A. It is a better kit."  I sent this very same question that I posted in the OP to them, I'll see what they have to say for the solution.  But I'm probably going to go after them with the better business bureau if they don't set things right.

Off hand, can anyone tell me how to differentiate a real VM30 from a fake?  I'd be royally pissed if they sold me fakes too.

Sorry if I'm a little incoherent.  I'm a bit pissed and don't feel like proof reading too much.

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28 Jul 2021 16:37 #852739 by SteveKing84
Replied by SteveKing84 on topic Dual VM30s on a KZ440. Anyone done it yet?
Is there anything special I should do with the line that runs from the top of the engine into the old airbox?

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  • Scirocco
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28 Jul 2021 17:38 - 28 Jul 2021 17:39 #852741 by Scirocco
Replied by Scirocco on topic Dual VM30s on a KZ440. Anyone done it yet?

Is there anything special I should do with the line that runs from the top of the engine into the old airbox?
Rout the line into a catch tank/bottle.It collects blowby moisture (cold start) and oil mist you can´t burnt through your missing air box.
Last edit: 28 Jul 2021 17:39 by Scirocco.

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29 Jul 2021 03:12 - 29 Jul 2021 03:14 #852766 by loudhvx
Replied by loudhvx on topic Dual VM30s on a KZ440. Anyone done it yet?
You can run it on prime until you know you have everything working.

Yeah, that's why I went with the Chinese knockoffs.  I knew any "kit" was still going to take a lot of extra running around and problem solving.  The knockoffs, with other parts required, ended up less than half the price of the kits.

In the build thread I included details about the main jets.  Real Mikuni will have a non-standard bolt thread.  The Chinese knockoff main jets use a standard thread.  This allows us to use Keihin, Teikei, and Dynojet main jets, which luckily we have a bunch laying around from our 550's.  So the main jet thread will distinguish the Chinese carbs from real Mikuni.  If they say Mikuni on them, like the photo Scirocco posted, they are more likely to be real.  The fake ones have no cast-in name. But I think the jet thread is a better method of distinguishing.

kzrider.com/forum/11-projects/611489-due...00-s?start=24#812095


 
Last edit: 29 Jul 2021 03:14 by loudhvx.

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