RS Acclerator Cables- what length/PN#?

[Rapid Dog]

1981 RS 40mm carbs

Installing a fresh updated throttle tube/cam.
That's all in and good and done.
When adjusting the cables I have to get adjust the bowden way out to get the slack out of the twist grip.
The knurled adjusters on the carbs have to go all the way in (down) to the nut to get any slack at the carb cables.

I'm looking at the butterfly and I see that the butterfly's aren't opening all the way, only about 3/4 open! No wonder I don't have any top speed!
I'm thinking someone put too long of lower cables on this bike.
They measure 16" on the cable housing, eye to eye.

Anyone got an idea what the correct PN# is?
Max shows #32731236616 - This cable is for HIGH BAR applications and is used with 40mm carbs.

But that can't be right!
This is an RS! It does have K-bike bars, but so what.
The cables on it have to be at least 1/2" too long.

[robert]

You may be one tooth off at the throttle cam.

[spo123]

I second Robert's opinion concerning one tooth off.....Been there.......It seems that All slack can NOT be entirely removed at the twist grip......I may be incorrect, however.......MINE adjusted out with just a small amount of slack.
TWO EXTRA POINTS for YOUR efforts and persistence in getting the "Bloodclot" set up AND FOR ALL OF YOUR EXCELLENT POSTINGS.
Ride Fast and Safe!
spo

[Roy Gavin]

In my experience getting the right part number and description on a sealed bag is no guarantee that you will be any better off than you are now.
It seems that the only certain way is to order by cable length and projection - if you want a 1250mm long cable with a 83 mm projection, adjuster tip to inside of nipple, then order it that way.

And I think that is the correct projection for a 40 mm carb, with the cable disconnected from the twistgrip, but I am open to correction.

[wirewrkr]

Okay, first off, you are looking at the wrong cables in the fiche. The 616 cables are for a 2 cable system, yours is a 3 piece unless it's been changed.
The 3 cables that should be on your bike are 1 upper 32731242128 and 2 lowers 32731242135
MOST importante, do you HAVE the correct cam?
The measurement for the 40mm cam is 18.25mm (approx) and for the 32 it would be approx 16.75mm
THIS measurement id from the center of the pivot to the center of the roll pin that holds the chain.
I've seen this happen before.
There's an answer

[Kurt in S.A.]

Anton has a good article on cables:

http://www.largiader.com/articles/cables/

Kurt in S.A.

[SteveD]

RD, if you need to buy all new bits, it might be worth considering the later, copied from the earlier, cam and two cable system.
Less parts and less fiddle.

[Rapid Dog]

It was the notch being off one, these later bikes are a learning curve for me.
Kinda wish I had the old system with two cables. Dog nose what I'll have to do for cables if I go with Mikunis or Dells...

[Roy Gavin]

Just made a pair of cables for 34 mm Mikunis, 32 mm are the same.

The BMW cables for 40mm carbs with 84 mm free length are perfect - the adjuster even screws into the top of the Mikuni.
All you have to do is change the nipple at the carb end to one 3mm diameter similar to the nipple at the twistgrip end, either by grinding it down or by unsoldering it or cutting it off and soldering a new one on.

The ferrule at the carb end screws off the cable so shortening the outer if you cut the nipple off or are adjusting the free length on other cables is no problem.

The stock carb to head rubber tubes will fit, but at the other end you need a couple of inches of 2 1/4" or 57 mm fuel filler hose and a couple of 70 mm clamps - the 64mm OEM ones just don't fit.

Someone out there makes proper moulded rubber adaptors which are the correct size each end, and are stepped in the middle to maintain a step free internal passage, but don't ask me who. RPC just has the hose

Fitting two long cables in place of a single and a splitter usually needs a new top as well as the cam,but if you are a cheapskate bodger like me it can be done with a bit careful work with a Dremel and a small drill.