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Old 05-03-2008, 09:59 AM   #1
Wirespokes OP
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Airhead Spliltter Throttle VS 2 Cables

I prefer the style of throttle that pulls two cables from the bar rather than the other that pulls just one.

For a long time I'd been wondering how to convert mine - it's a 77S that was converted by a PO to handlebar mounted Master Cylinder. But since it needs new cables I wanted to convert to the dual cable system first.

Finally I saw on Snowbum's site that the 1985 to 95 airheads returned to the dual pull system and that was just the info I needed. I was beginning to think I would need to do some fancy machining to convert this single pull to a dual.

I've got two questions: one is that snowbum says he prefers the single pull system using the splitter. I don't understand that. He doesn't elaborate, but for one, the splitter is added complexity that doesn't seem to help. Any idea why he would prefer that style? Also, since BMW returned to the dual pull system after four years tells me they found that system better as well. What are your thoughts on this?

I'm considering mounting a set of Dellortos on this bike and with a dual pull system could get standard 90S cables rather than have something special made up. But even if I don't do that, I just don't like those splitters and prefer the positive pull to each carb rather than something in between with added friction.

Is there something I'm missing? I can see that it's a good idea having less cables to the controls which would translate to less resistance turning lock to lock. But other than that, I see nothing else on the positive side of the ledger. And, if you happen to have one of these controls you'd consider passing on to a good home, let me know.
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Old 05-03-2008, 10:02 AM   #2
lkchris
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It's my experience that the one-into-two system is a big improvement.

Every year or so, I put my carb balance checker on just for fun--my carbs always stay balanced. Lot less cable to stretch. Can think of no earthly reason to prefer the dual-cable setup.
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Old 05-03-2008, 12:18 PM   #3
benway
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Quote:
Originally Posted by tvrla
I'm considering mounting a set of Dellortos on this bike and with a dual pull system could get standard 90S cables rather than have something special made up.
iirc the S/dellorto throttle cam is different than the stock /6, because of the heavy pull on the slides vs bings
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Old 05-03-2008, 08:40 PM   #4
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Quote:
Originally Posted by lkchris
It's my experience that the one-into-two system is a big improvement.

Every year or so, I put my carb balance checker on just for fun--my carbs always stay balanced. Lot less cable to stretch. Can think of no earthly reason to prefer the dual-cable setup.

All the splitter boxes I've come across have a limited range of movement of about 36mm. If you have a 38mm slide carb like on the R90s you need the cables to move at least 38mm ( and a bit more for free play) so a splitter that only moves 36mm ain't no good.
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Old 05-04-2008, 08:54 AM   #5
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I didn't know that about the limited splitter range of movement. Guess I'd have to convert over. I'd also thought the throttle gears were the same, at least for the larger displacement bikes. I'd heard the 32mm bings used a different gear than the 40s, but other than that I'd assumed they were all the same. I'll have to research the parts fiche.
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Old 05-04-2008, 09:22 AM   #6
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I agree, the splitter system stays in sync better especially as the handlebar is turned. It's slightly more fussy to set up, it has more parts, and the splitter gets all rusty and cruddy when the boot rots away (which takes about 8~10 minutes), but when the parts are in good shape and the splitter is positioned so as to allow nice cable bends, it works well and holds sync really nicely.

The throttle cam gear history is pretty convoluted and I haven't fully deciphered it yet. What little I know about it is on my website under the 40mm stuff, on an orphan page:

http://www.largiader.com/articles/40mm/

There are a whole lot of throttle cams. I haven't listed them all yet.
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Old 05-04-2008, 11:08 AM   #7
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i believe my PD has a dual-throttle, and splitter-choke setup.
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Old 05-04-2008, 08:27 PM   #8
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Quote:
Originally Posted by Stagehand
i believe my PD has a dual-throttle, and splitter-choke setup.

same here...
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Old 05-04-2008, 09:01 PM   #9
datchew
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Quote:
Originally Posted by Stagehand
i believe my PD has a dual-throttle, and splitter-choke setup.

Ditto on my 89 GS. If you clean and lube the internal slider of the choke 1 into 2 setup, then you can cocoon the outside of the plastic cap with clear silicone and it lasts alot longer. When you want back in, simply cut and peel.

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Old 05-04-2008, 11:07 PM   #10
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All of the bikes after 84 have the two cables throughout. The difference between the GS and the others is that the GS used the K bike controls for some reason unknown to me. Perhaps to make it special with different switches? The GS (and R100R) have a square master cylinder reservoir and that's one of the distinguishing features.

Thanks Anton - that's some great data.
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Old 05-05-2008, 02:55 AM   #11
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Quote:
Originally Posted by tvrla
...the GS used the K bike controls for some reason...

The R100R as well...
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Old 05-05-2008, 03:51 AM   #12
AntonLargiader
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Quote:
Originally Posted by tvrla
All of the bikes after 84 have the two cables throughout. The difference between the GS and the others is that the GS used the K bike controls for some reason unknown to me.
Actually the R100GS only used those controls '91-on, but had the twin throttle cables from the beginning in '88. I like the Kontrols better, so I will probably (this is about 18th on the list, right after cutting off that R65 SH for you) convert my '88 to them when I repaint it and bump the compression. Hmm, if I dropped everything else I bet I could get that done in time for XPLOR Blue Ridge....

BTW I was hoping to get Stagey to cut that frame up for you but forgot to twist his arm.
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Old 12-18-2011, 02:29 AM   #13
boxerboy81
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Is there a trick to removing the two lower cables from the splitter?



.
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Old 12-18-2011, 04:20 AM   #14
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Quote:
Originally Posted by boxerboy81 View Post
Is there a trick to removing the two lower cables from the splitter?
It's been a while since taking one of those apart, but I seem to recall needing the top one (from the throttle) free, which will allow the internals to slide out far enough. You may have to screw in the adjuster also to give more slack.
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Old 12-18-2011, 04:32 AM   #15
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Quote:
Originally Posted by Wirespokes View Post
It's been a while since taking one of those apart, but I seem to recall needing the top one (from the throttle) free, which will allow the internals to slide out far enough. You may have to screw in the adjuster also to give more slack.

Thanks.
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