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CR Throttle Bodies not closing completely

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The CR Linkage is rather uncomplicated. The thing I am really not liking is the fact it is all handled thru the first Throttle Body (TB) of 1st and 2nd Cylinder.

TB 2 and TB 3 are connected thru the spindles with a set screw and spring loaded pin.

I have an additional spring between Lever (98) and Bracket (108). This Spring remains however, loose and is not able to close the TB completely.

This is especially the case for the middle TB (Cylinder 3-4).

After I set the TBs according to the manual thru the set screw and sping loaded pin, I had a very bad idle running around 1300.

After I released all screws and cable, Idle was around 950. This means, the TB discs are closed and fit. But for some reason, after proper setup the TBs do not seem to close. 


- any advise on the springs or how to setup the Throttle Link (100) vs the Adjustment Screw at the Cable

- any thoughts on this linkage? maybe swap out for upgrated version from Malcolm (Prestige Injection) or Revington? They are expensive !!






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I would first suspect wear on the spindles and that the manifolds are not lined up properly as there was a jig to line up them in production which is sometimes for sale om e-bay! I have used a 1m straight edge in the past to help line them up across the tops. It is not as good as the jig? To check the closure use a .002" feeler gauge between the butterfly disc and body, s/b a slight tightness. The butterfly return spring do go weak with age?


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Hello Bruce, the spindles run in bearings. The CR Bodies are connected thru those brackets and use a set screw and spring loaded pin. This allows for some tolerance.

.002 " feeler gauge was used and everything is fine. It seems that the spring may be weak and needs to be replaced with a stronger one....


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Hi Jochem,

have you tried a thin lubricant, also in the middle bearing of each TB spindle? This may help a bit, although it would not be a permanent solution.

I aligned my CP TB’s with a straight edge, and measured the distance between the straight edge and the spindles, to have them as close as possible. For CP TB’s I don’t think the alignment between the 3 items is very critical, since each one is activated with an individual lever.For CR TB’s this is different off course.

Fitting new springs may be a good idea, but remember not to go stronger than original, as wear will increase.




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Hi Jochem

I had a similar problem after  adjusting the TB's on my Cr.  I found by re adjusting the throttle linkage (no 100) and throttle cable I was able to get the engine to idle happily at 750/800 rpm.  I am not sure where the spring is positioned but will have a look tomorrow for you. Stick with it.


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