Page 1 of 1

Worn sliding dog?

PostPosted: Sun Mar 14, 2021 4:51 pm
by Danbretta
I occasionally get an issue with the scooter jumping out of 2nd gear when accelerating. It seems to happen more when loading the gears pulling away up hill.
Would this be down to a worn sliding dog or weak springs in the lay shaft?
If I dont push too hard through the gears it seems to go ok.
Any ideas lads?

Re: Worn sliding dog?

PostPosted: Sun Mar 14, 2021 5:57 pm
by missing lynx
Could be over tight cables

Re: Worn sliding dog?

PostPosted: Sun Mar 14, 2021 6:04 pm
by Danbretta
I'll have a look, thank you

Re: Worn sliding dog?

PostPosted: Sun Mar 14, 2021 6:52 pm
by Warkton Tornado No.1
They wear with rounded corners, causing jumping out of gear under power.

IMO there is none available better than OEM Innocenti or Eibar.

I've been through dozens of SIL & other 'replacements' & they do not compare.

Fortunately, I have kept all of my OEM cast offs & regrind the faces square in a DIY jig.

The best uprated springs were from SIP as they kept their 'temper'

Re: Worn sliding dog?

PostPosted: Sun Mar 14, 2021 8:40 pm
by Danbretta
I may have to strip it out and have a look, I think I'm due to put the chain guide in now the new chain has stretched enough. So while I have the chaincase off I'll have a look over the faces and square them up. I'll see if I can pick up some stronger springs before hand. Thanks for the advice.

Re: Worn sliding dog?

PostPosted: Fri Mar 19, 2021 11:42 am
by Scooterslag
Warkton Tornado No.1 wrote:They wear with rounded corners, causing jumping out of gear under power.

IMO there is none available better than OEM Innocenti or Eibar.

I've been through dozens of SIL & other 'replacements' & they do not compare.

Fortunately, I have kept all of my OEM cast offs & regrind the faces square in a DIY jig.

The best uprated springs were from SIP as they kept their 'temper'


I've got a couple of OEM sliding dogs that I'm sure are ok but not entirely sure if they are too worn, whats the minimum size before they are fit for the bin? also does anyone offer the regrinding of them back to square? I know Taffspeed offered this service years ago but things have changed with them. Paul

Re: Worn sliding dog?

PostPosted: Fri Mar 19, 2021 2:05 pm
by Warkton Tornado No.1
Scooterslag wrote:
Warkton Tornado No.1 wrote:They wear with rounded corners, causing jumping out of gear under power.

IMO there is none available better than OEM Innocenti or Eibar.

I've been through dozens of SIL & other 'replacements' & they do not compare.

Fortunately, I have kept all of my OEM cast offs & regrind the faces square in a DIY jig.

The best uprated springs were from SIP as they kept their 'temper'


I've got a couple of OEM sliding dogs that I'm sure are ok but not entirely sure if they are too worn, whats the minimum size before they are fit for the bin? also does anyone offer the regrinding of them back to square? I know Taffspeed offered this service years ago but things have changed with them. Paul


Taffspeed used to sell refurbished cursors & I heard they were "as good as new"

Whether they were welded & dressed or metal sprayed, I am not aware. Metal spraying gives a huge choice of hard materials & would be my choice.

I have no idea of what a sensible minimum dog thickness would be, but I select the best I have & just redress the driving faces. It's taken me years to get the process right, ensuring consistency & squareness, but IMO there is no alternative. The SIL items are mis-machined & the metallurgy of 'reknowned' manufactured ones are wrong as they can be brittle & crack.

The 'fixture' I use is nothing too elaborate but involves a tool that I would not want to be without. A power file. Mine is a Makita, but others are available. Extremely useful for porting crankcases & the bigger cylinder transfers in conjunction with die grinders......

Re: Worn sliding dog?

PostPosted: Fri Mar 19, 2021 3:29 pm
by Scooterslag
Warkton Tornado No.1 wrote:
Scooterslag wrote:
Warkton Tornado No.1 wrote:They wear with rounded corners, causing jumping out of gear under power.

IMO there is none available better than OEM Innocenti or Eibar.

I've been through dozens of SIL & other 'replacements' & they do not compare.

Fortunately, I have kept all of my OEM cast offs & regrind the faces square in a DIY jig.

The best uprated springs were from SIP as they kept their 'temper'


I've got a couple of OEM sliding dogs that I'm sure are ok but not entirely sure if they are too worn, whats the minimum size before they are fit for the bin? also does anyone offer the regrinding of them back to square? I know Taffspeed offered this service years ago but things have changed with them. Paul


Taffspeed used to sell refurbished cursors & I heard they were "as good as new"

Whether they were welded & dressed or metal sprayed, I am not aware. Metal spraying gives a huge choice of hard materials & would be my choice.

I have no idea of what a sensible minimum dog thickness would be, but I select the best I have & just redress the driving faces. It's taken me years to get the process right, ensuring consistency & squareness, but IMO there is no alternative. The SIL items are mis-machined & the metallurgy of 'reknowned' manufactured ones are wrong as they can be brittle & crack.

The 'fixture' I use is nothing too elaborate but involves a tool that I would not want to be without. A power file. Mine is a Makita, but others are available. Extremely useful for porting crankcases & the bigger cylinder transfers in conjunction with die grinders......


Thanks for the reply WT, as I don't want to hijack this thread I've set up a new thread with piccies of my sliding dogs - be interested to see if you think they're ok to run as or need grinding/reprofiling , cheers Paul

Re: Worn sliding dog?

PostPosted: Fri Mar 19, 2021 4:31 pm
by Solid Air
missing lynx wrote:Could be over tight cables


Or cable routing