Gearbox query….

[Gritman]

Hi folks, 

Its been a while, but I need your collective knowledge on a gearbox issue causing me a lot of brain strain. Finished a project bike last summer and ran it in a treat - apart from a clunk in the transmission when rolling throttle on/off. Made note to self to investigate/correct over winter. First checked bevel box and shaft, all ok so gearbox it is. 
With the box on the bench it becomes apparent that the selector dogs are the cause and as such, no adjustment is available. Im getting in excess of 30 degrees of lash between input and output shafts………. This can’t be right, surely.  I have changed the dogs as per Recall notice to no effect. Can anyone confirm that this is normal/acceptable, and if not, how can I reduce this, given the free play between the dogs and its gear are fixed, and each dog acts on one gear at a time?

Thanks,

Chris

[Pressureangle]

What gearbox is it? 5-speed, or 6?

My straight-cut 5 speed takes about a quarter mile to take up the slack between rolling the throttle on and off, due to having only 3 dogs per gear.

[Gritman]

It’s a six-speeder, probably pre 2002……

[MartyNZ]

Pete Roper made some comments about gearbox backlash here:

https://www.v11lemans.com/forums/topic/25672-light-rattle-in-gearbox-when-pushing-my-bike/?do=findComment&comment=278017

 

[Gritman]

Thanks for that Marty…. I’d not seen that thread. Pete Roper’s contribution seems to support my theory that it’s all down to the selector dogs. TBH, it’s already for reassembly and I’m just holding out on gasketting and torquing up the shaft nuts in case there is a magic fix somewhere! 

 

[MartyNZ]

Are you going to post some pictures of the project bike?

[pete roper]

Was the driveshaft properly assembled and aligned when it was making this noise?

[Gritman]

Hi Marty,  just gotta get some photos off my phone so I can edit them down to the acceptable size…..

Pete, thanks for your interest. The driveshaft assembled/aligned correctly. The bike did about 1300m running in and the gearbox backlash was the only issue that arose. I do run anther bike using the V11 box/transmission on stock items that does not display the symptoms. I think that perhaps the relatively unforgiving cush drive in the Dymag, combined with replacing the stock metalastic bushed torque reaction bar with a rose-jointed item has magnified the issue somewhat…. Maybe it’s just something I need to get used to!

[pete roper]

I'd say that your suggestions are probably correct.

[Gritman]

Thanks Pete, I think it’s time to stop navel gazing and reassemble the gearbox….. liked your description of the dogs knocking the bejasus out of themselves! Hope the replacements are up to the job 🤞

[Gritman]

Well, reducing photo size is nearly as much fun as rebuilding gearboxes😂

Heres my baby, hope image quality hasn’t suffered too much!

[docc]

5 minutes ago, Gritman said:

Well, reducing photo size is nearly as much fun as rebuilding gearboxes😂

Heres my baby, hope image quality hasn’t suffered too much!

Wow, stunning! I have  always loved "Gulf" racing colors and the Gulf/Guzzi logo is clever!

Is this an early V11 (199-2001) short frame, or a later LongFrame ?

[edit: oh, wait, the Centauro frame?]

What are those wheels??

[Gritman]

Hey Doc, thanks for your comments😊 it’s a tarted-up Centy…. 1225 conversion, Dymags, Ohlins, full Motogadget, lithium battery and other weight saving mods. Weighs in at 187kg. It’s been a labour of love, but I’ve finally got the Guzzi I wanted - apart from the tranny lash of course😬

[docc]

Very interesting bike! Nicely done, Sir!

I am curious about the wheelbase and fork rake of the Centauro frame (?)

BTW, you can create an Album in Member Galleries to share more pics of your bikes without the resizing issue . .

 

[docc]

Oh, hey, @Gritman, you already have an album you can add images to!

https://www.v11lemans.com/forums/gallery/album/139-the-babies33/