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Old 12-18-2011, 01:09 PM   #16
because I can
Joined: Sep 2010
Location: San Francisco Bay area
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I am in the same boat you are in Ws. I am running Dellorto's so I pretty much have to run two separate cables. I would run the splitter otherwise. They stay in sync a lot better with the splitter. I think BMW quit using the splitter because with the stock setup they almost instantly fill with grit from road wash running down the cable and into the boxes. The very simple solution is to put some electrical wire shrink tubing over the single cable before you assemble the splitter. Set it up and then slide the shrink tubing over the cable adjuster and shrink it on the cable. I know from experience that they will stay perfectly spotless inside for tens of thousands of miles and tens of years thusly modified. I have always put a dab of lithium grease and Tri Flow in mine. Works perfect.

Running Dell's? I am pretty sure they need a different throttle cam to open up all the way although I do think the longer travel cam opens the slide up too much. That might hurt more than it helps but I don't know. I would check it out on a flow bench if I had one. I am pretty sure one 40mm cam has a lot more progressive pull than another that is available. I filed my velocity stack threads about half way down (you can use the width of the threads as an indicator in order to keep the project round) and then the later model snorkel tubes fit perfectly right on to the carbs minus the convoluted R90S setup with radiator hose on it.

Like I always try to help with, don't forget that R90S stock jetting is way rich. The pump can't be turned off enough without completely disconnecting it but that requires completely rejetting just off idle. My bike with a sport cam, mild port work, and Staintune sport mufflers made more and more power until I got down to 130 mains. If I ever mend up I can't wait to see what it will take now with some serious port work (still not flowed however), 44mm intakes up from 42's, and dual plugged with a theoretical 10:1 compression ratio. I have 140's in it right now just to be safe during brake in. I won't be surprised if I end up right back with 130's but we shall see.

Limited splitter range of movement? I have never tried opening up a Dell with a splitter but I would think it would work? Both 32 and 40mm carbed bikes use the same splitter.

supershaft screwed with this post 12-18-2011 at 02:15 PM
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Old 12-19-2011, 08:25 AM   #17
Wirespokes OP
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Location: Jackson's Bottom Oregon
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Good points SS. It appears the 90S throttle cam (for use with Dels) is the same as the RT, RS and S with the 40mm Bings. So no problem there.

I do have a dual pull control (no splitter) so don't have to worry about that either. I haven't noticed the dual cables going out of synch any sooner than the other. And your observation on the splitter possibly not providing enough length for the Dels isn't something I'd even thought about. I just like the simplicity of the system without the splitter. One thing I do like about the splitter system is there's only one cable flexing when turning = less resistance and less mass routed through an already tight space.

Currently I'm looking for a set of Dellortos - probably PHF 34mm or 36mm - to run on my 850 R65. It's got 34mm flat slide mikunis currently but think I'd like to try the Dels. Anyone got a set they'd like to sell?
Wanted: Dead, smashed, crashed or trashed gauges
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Old 12-19-2011, 09:51 AM   #18
Bored Of The Rings
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Joined: Jun 2011
Location: Auckland,New Zealand
Oddometer: 1,718
I replaced the splitter set up my Ducati many years ago with dual cables and it holds tune very well, my Norton on the other hand has a splitter and doesn't....personally I'm with less is more as far as interfaces go.
I'm building a 900 BMW track bike and using a set of 36mm Dells, The inlet to the 900 heads is 36mm and a friend turned me up some adapters .looks good so far..with a bit of luck I can use the std air cleaner tubes.
Also using a Tommaselli Twin 1/4pull throttle as I don't like the geared one....the KISS principle......although I need a separate starter button.
The 36 mm carbs were used on Pantahs.Bevel Heaven sell the carbs, I got the rebuild kit from the UK.
I used R90s jetting as the start point but sounds like it may be too rich.
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Old 12-19-2011, 09:53 AM   #19
Airhead Wrangler
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Originally Posted by supershaft View Post
Limited splitter range of movement? I have never tried opening up a Dell with a splitter but I would think it would work? Both 32 and 40mm carbed bikes use the same splitter.
But you don't have to pull a slide the full height of the throat on the bings. You're just turning a lever to open butterflies. A 40mm slide carb will NEED about 38mm of cable pull to open fully due to the fact that the slide is cracked open just a little at idle to set idle speed. I'd want to be able to pull at least 42mm of cable just to allow a little free play.
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Current rides: HPN #834, '93 R100GSPD "red rocket", '73 R75/5 Toaster mongrel, '80 Ducati Pantah 500SL, '92 DR350, '67 Honda SS50, '80 Honda Chaly.
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