ET: Engine (Twin) Rapide Gearbox - Very 'tight' gearchange

Phil Arundel

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I have just assembled the gearbox on my Rapide and find that the gearchange is very 'tight'.
I am having great difficulty in easily selecting each gear.
The gear cluster, quadrant plate and selectors are all new.
Has anyone come across this problem & how to solve it please.
 

Bill Thomas

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I have just assembled the gearbox on my Rapide and find that the gearchange is very 'tight'.
I am having great difficulty in easily selecting each gear.
The gear cluster, quadrant plate and selectors are all new.
Has anyone come across this problem & how to solve it please.
Is it still dry on the bench ?, It might be just the pawl spring too tight ?,
They can feel tight untill they are lubed.
Cheers Bill.
 

Robert Watson

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I recently put a Quaife and new detent plunger and spring in a B Rapide. As soon as it was together I wanted to run it through the gears to be sure all was well and I didn't think it would ever change gears. I didn't recall this from the first one.
Long story short after a few miles it improved greatly and now with a few hundred on it it is 95% there.

I have always said with these old bikes, when you put new parts in them it takes a little while for them to all make friends and get to know each other, then the magic happens!

Robert
 

robmfj

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That's encouraging Bill. I am in a similar situation having fitted a new Surtees 5 speed bundle and apart from assembly lube have found it tight (probably not "very"). Consequently, not easy to find that sweet spot with the shift mechanism. Was hoping that filled with oil and a few RPM applied it will become easier. I have been advised that it will take up to 500 miles to ease completely. The palm of my left hand suffered from constant manual turning of the clutch shaft trying to get it sweet. Then made up some lock nuts and able to spin with an air gun, this proved to me that the 5 gears and N were all there so left it at that and now having read Robert's post I am further encouraged that things can only get better. Still a ways to go before the bike will be finally up and running.
What would be the best oil for a new "tight" gearbox?
Rob
 

Bill Thomas

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It's just me, But I think engine oil is for engines, I like 80 or 90 in mine, But I have never run a 5 speed.
Maybe to start with you should do what Surtees says. Cheers Bill.
 

Robert Watson

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I run BelRay 80-90 in my gearboxes. Made for just that purpose. Not sure if this is juat a North American product but there must be an equivalent EU oil.

I have been told that multi grade engine oil are not good as the gears shred the polymer that make it go thicker..
 

oexing

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VOC Member
I did not like the type of detent, the pointed plunger gets a lot of side load when changing gear . And that is subject to a lot of friction in the bore. So I copied the BMW lever type for hopefully smoother shifts - at least in dry condition it works reasonably well so I am very confident . . . .
Als o the camplate does not rest on the selector forks but is fixed by a top hat nut.

Vic
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