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 Post subject: Re: New VM38's
PostPosted: Tue Oct 24, 2017 6:58 am 
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Joined: Thu Jun 16, 2011 10:19 am
Posts: 191
Location: Wellington, Fl
jyrgNorway wrote:
Cool.

What UFO's are you using? 2.5, 3.0 or 3.5 cut out?

Over here, we are a couple running VM38's. We both use Q2 NJ. If leaner, Power went Down in the 1/4th throttle openings area. Funny thing is the other one does not use UFO, but Stock 2.5 slide. I use UFO 3.5. Still we both ended up at Q2. I think I have 12.5 or 15 pilots. I think he has 35 or 40.

I am not saying Your intake runners are too short, but they may be. I did a lot of dyno testing for the purpose of finding the shortest intake runners lenght as possible (for fitment reasons) befor Power in the low/mid went Down. My Intake runners has then Ramair 70mm fitted outside the silicone tubes for Maximum air flow. And I found the minimum length to be in the 200mm area, before Power went Down.
I have about zero experience With TM34's. But I can assure you the 38's will boost Power at all revs all the way from 3000 to max versus VM's. So, I believe you will feel Power icrease over TM's as well, but maybe not in same extent. Make sure you are able to give 100% full throttle. I had to adjust the splitter. It is a couple of horses to be gained there as well. And the perpendicular to bore carb position also gived you a Nice little Power gain over conventional carbs position. Don't know exactly how much though....maybe 3-4 rwhp???

What heads do you have?

Oh.......and Your bike looks GREAT by the way, I also like those pipes very much.

Good Luck With the tuning :thumbup:

Jørgen

Using 3.5 slides with Jim's UFO's. The motor was 4 stroking with Q-2 NJ and plugs were black. The intake runners are about 130 mm long, could have got longer ones in there I guess. I got away with shortening the outer throttle cable sleeves, carbs will open to full throttle. The port / head work was done by Tony Nicosia. Pipes are FBG. Thanks again for your advise and jetting info.... :D


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 Post subject: Re: New VM38's
PostPosted: Tue Oct 24, 2017 1:56 pm 

Joined: Sun Sep 09, 2012 10:26 am
Posts: 797
Aaaaaa....TonyNicosiaTuned. I bet that thing's gonna fly then, he has quite some experience :thumbup: :thumbup:

And maybe it would be Worth a try JB Welding the intake son the transition between inlet rubber and inlet duct become smooth, and also that you Ensure a Nice tapered duct as well (about Stock layout). But I'm on thin ice here, as I have not seen Your intake or dynoed such cylinder before/after

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 Post subject: Re: New VM38's
PostPosted: Tue Oct 24, 2017 2:11 pm 
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Joined: Wed Jun 08, 2011 10:23 pm
Posts: 3821
Location: Colorado Springs, CO. USA
I see these on eBay all the time. Mikuni VM34 34mm Round Slide Carburetor Kit UFO.

https://www.ebay.com/itm/Kawasaki-H2-750-72-75-Mikuni-VM34-34mm-Round-Slide-Carburetor-Kit-UFO/172333377394?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649

Kit includes: Pre-jetted Mikuni round slide VM carbs fitted with UFO slide modifiers, Mikuni flange adapters, and washable and reusable oiled air filters. Carburetors are pre-jetted for stock or very mildly modified engines.

Uses the factory throttle, and choke cables
Slides are pre-fitted with UFOs
Carburetors, and internal jetting components are Genuine Mikuni Products
Includes two additional sizes of main jets: 240 and 250
We ship these all over the world. Engine setup (especially chamber type, and porting), location, and type of fuel used will all have an effect on the requirements of the engine. We jet these to what we have seen apply to the majority of applications for stock, or mildly modified engines. We include additional jetting in such instances where the out of the box setup is not adequate.


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Last edited by BarryB on Tue Oct 24, 2017 2:18 pm, edited 2 times in total.

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 Post subject: Re: New VM38's
PostPosted: Tue Oct 24, 2017 2:15 pm 
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Joined: Wed Jun 08, 2011 11:34 pm
Posts: 9826
Location: North Central NC
Are those 34s Barry?

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 Post subject: Re: New VM38's
PostPosted: Tue Oct 24, 2017 2:19 pm 
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Joined: Wed Jun 08, 2011 10:23 pm
Posts: 3821
Location: Colorado Springs, CO. USA
Yes Jim. I updated my post.

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This is true. Where I grew up the hills were so steep and long, when your ball rolled down the hill you just said "screw it"...


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 Post subject: Re: New VM38's
PostPosted: Wed Oct 25, 2017 6:18 pm 
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Joined: Thu Nov 21, 2013 7:07 am
Posts: 85
Location: Sweden
soflah2b wrote:
The intake boots are Harley Davidson compensator boots. Two front and one rear or two rear and one front. Bolt pattern had to be modified on one side.
Would these work?

Look at this on eBay http://www.ebay.com/itm/192211728898


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 Post subject: Re: New VM38's
PostPosted: Thu Oct 26, 2017 5:18 am 
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Joined: Wed Jun 13, 2012 9:00 pm
Posts: 971
Location: Eagle Wisconsin
h2b780 wrote:
soflah2b wrote:
The intake boots are Harley Davidson compensator boots. Two front and one rear or two rear and one front. Bolt pattern had to be modified on one side.
Would these work?

Look at this on eBay http://www.ebay.com/itm/192211728898


I found one old used one on ebay for $7.00 so I ordered it to see how it will work. I have been looking for a way to do this without a bunch of work and expense. If it looks good and works I will order some new ones.

Good info soflah2b :thumbup:


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 Post subject: Re: New VM38's
PostPosted: Thu Oct 26, 2017 5:39 am 
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Joined: Thu Jun 16, 2011 10:19 am
Posts: 191
Location: Wellington, Fl
demus wrote:
h2b780 wrote:
soflah2b wrote:
The intake boots are Harley Davidson compensator boots. Two front and one rear or two rear and one front. Bolt pattern had to be modified on one side.
Would these work?

Look at this on eBay http://www.ebay.com/itm/192211728898


I found one old used one on ebay for $7.00 so I ordered it to see how it will work. I have been looking for a way to do this without a bunch of work and expense. If it looks good and works I will order some new ones.

Good info soflah2b :thumbup:

yes they will, but don't buy after market, buy factory HD. They are about $18 each. I tried the cheaper after market boots and had problems with them coming apart after modifying the one bolt hole.


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 Post subject: Re: New VM38's
PostPosted: Thu Oct 26, 2017 10:19 am 
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Joined: Thu Nov 21, 2013 7:07 am
Posts: 85
Location: Sweden
soflah2b wrote:
demus wrote:
h2b780 wrote:
soflah2b wrote:
The intake boots are Harley Davidson compensator boots. Two front and one rear or two rear and one front. Bolt pattern had to be modified on one side.
Would these work?

Look at this on eBay http://www.ebay.com/itm/192211728898


I found one old used one on ebay for $7.00 so I ordered it to see how it will work. I have been looking for a way to do this without a bunch of work and expense. If it looks good and works I will order some new ones.

Good info soflah2b :thumbup:

yes they will, but don't buy after market, buy factory HD. They are about $18 each. I tried the cheaper after market boots and had problems with them coming apart after modifying the one bolt hole.
ok thanks! :thumbup:


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 Post subject: Re: New VM38's
PostPosted: Thu Oct 26, 2017 6:24 pm 
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Joined: Wed Jun 13, 2012 9:00 pm
Posts: 971
Location: Eagle Wisconsin
I got the old used HD compinsater boot to see how it might fit, below are some photos.
Not sure how you managed soflah2b, maybe there are some differences in them, I though this was an old stock harley part but maybe not. This one is marked as the rear boot.
I too have reeds so the mating surfaces on the cylinder are no where close to stock size like yours.
But the bolt holes are far enough off to make it seem like just re-drill of the boot may not work for me.
Any advice from when you fit yours??
Thanks in advance!

ImageH2 intake with compositor boot by Joe Herriges, on Flickr

ImageH2 intake with compositor boot by Joe Herriges, on Flickr

ImageH2 intake with compositor boot by Joe Herriges, on Flickr


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