LCGB Forums

The ability to post messages is restricted to LCGB members. Any questions contact us at lcgbadmin@googlemail.com

Series 3 lower headset rebuild on the bench

Technical help for Series one, two and three Lambrettas. Models include the Li, Li Special, TV, SX, GP, Serveta and API/SIL models

Series 3 lower headset rebuild on the bench

Postby jdevane5 » Thu Aug 05, 2021 9:39 pm

I'm just in process of a lower headset rebuild and have done the clutch side,no cables attached yet, lower head seat still on the bench getting built up
My question is how should the feel of the gear change be? Really easy? Or with a very slight bit of friction(How I have it), but feels direct.
I've used all the original parts and given them a good clean up / greasing.

If slightly stiff gear change -is it a case of replacing all parts?
jdevane5
 
Posts: 107
Joined: Mon Oct 14, 2019 8:53 pm

Re: Series 3 lower headset rebuild on the bench

Postby missing lynx » Thu Aug 05, 2021 10:22 pm

It should have no resistance at all, the weight of the lever should move it. It could be something simple like to much paint or the shim between the gear wheel and the clamp. So I would just check all the components movement before you start throwing money at it
missing lynx
 
Posts: 863
Joined: Wed Nov 26, 2014 5:14 pm

Re: Series 3 lower headset rebuild on the bench

Postby Fast n Furious » Fri Aug 06, 2021 12:31 am

It would also be a good idea to relieve the area where the clutch cable enters into the casting, with a Dremel. This reduces the friction that the cable places on the gear control rod. Sticky's manual is a good reference here. ;)
User avatar
Fast n Furious
 
Posts: 1502
Joined: Sat Nov 19, 2016 3:56 am
Location: York

Re: Series 3 lower headset rebuild on the bench

Postby Warkton Tornado No.1 » Fri Aug 06, 2021 1:13 pm

It's always worth spending time on the control rods & the bearings that they rotate in. Often the rods are not dead straight but can be corrected.

I think the OEM plain bearing components (top hat, olive etc) were not just nylon, but an oil impregnated material, which is far less likely to swell like the cr@p replacements.

If you are not already aware, the saddle clamps that retain the olives can have a washer fitted beneath them to act as a shim to prevent any binding. Best fitted with SHCS's which are M4 though if the threads are dodgy, a stud with nylocs will do.

I know you haven't got there yet, but the screws that pull the top onto the bottom headset are M5. I have used SHCS's for decades with a ball ended hexagonal key & that makes the job so easier & 'non-slip' as far as the tool goes. Yes, I know the holes are countersunk rather than counterbored, but the SHCS's never come loose...... ;)
Warkton Tornado No.1
 
Posts: 2112
Joined: Sun Jan 11, 2015 1:27 pm

Re: Series 3 lower headset rebuild on the bench

Postby jdevane5 » Fri Aug 06, 2021 4:44 pm

Cheers for all the pointers, will have a strip down and rebuild the lower head set this weekend.
Not rushing the build.

JD
jdevane5
 
Posts: 107
Joined: Mon Oct 14, 2019 8:53 pm

Re: Series 3 lower headset rebuild on the bench

Postby Warkton Tornado No.1 » Sat Aug 07, 2021 1:17 pm

Now is the time to consider the throttle pulley size. Perhaps because I've always tended toward larger carburettors, I prefer the gearchange pulley for the response. That or my wrists are just getting old & tired......

If fitting the larger pulley, the lower headset rib has to be relieved. The pulley 'stop' is an M5 screw & nut through the upper of the two cable holes & a solder-less nipple grips the throttle cable.

Self closing is a definite safety feature & was a standard feature of some Servetas:

http://www.scooterrestorations.com/lamb ... eta-n.o.s/

You can buy the spring or just modify a normal tension spring that fits over the rod. Modification requires fashioning one end to create a loop to fit the saddle clamp hole while the other can be anchored to the rod via the head of a split pin that in turn fits a hole drilled in the rod. Just make sure that nothing can snag the front brake cable or lighting contro/horn lead.
Warkton Tornado No.1
 
Posts: 2112
Joined: Sun Jan 11, 2015 1:27 pm

Re: Series 3 lower headset rebuild on the bench

Postby missing lynx » Sat Aug 07, 2021 1:31 pm

Warkton Tornado No.1 wrote:Now is the time to consider the throttle pulley size. Perhaps because I've always tended toward larger carburettors, I prefer the gearchange pulley for the response. That or my wrists are just getting old & tired......

If fitting the larger pulley, the lower headset rib has to be relieved. The pulley 'stop' is an M5 screw & nut through the upper of the two cable holes & a solder-less nipple grips the throttle cable.

Self closing is a definite safety feature & was a standard feature of some Servetas:

http://www.scooterrestorations.com/lamb ... eta-n.o.s/

You can buy the spring or just modify a normal tension spring that fits over the rod. Modification requires fashioning one end to create a loop to fit the saddle clamp hole while the other can be anchored to the rod via the head of a split pin that in turn fits a hole drilled in the rod. Just make sure that nothing can snag the front brake cable or lighting contro/horn lead.

Or you could just buy a ready made quick action throttle pulley. I must admit I like my throttle not to snap back it makes right hand signals easier.
missing lynx
 
Posts: 863
Joined: Wed Nov 26, 2014 5:14 pm

Re: Series 3 lower headset rebuild on the bench

Postby Warkton Tornado No.1 » Sun Aug 08, 2021 12:44 pm

missing lynx wrote:
Warkton Tornado No.1 wrote:Now is the time to consider the throttle pulley size. Perhaps because I've always tended toward larger carburettors, I prefer the gearchange pulley for the response. That or my wrists are just getting old & tired......

If fitting the larger pulley, the lower headset rib has to be relieved. The pulley 'stop' is an M5 screw & nut through the upper of the two cable holes & a solder-less nipple grips the throttle cable.

Self closing is a definite safety feature & was a standard feature of some Servetas:

http://www.scooterrestorations.com/lamb ... eta-n.o.s/

You can buy the spring or just modify a normal tension spring that fits over the rod. Modification requires fashioning one end to create a loop to fit the saddle clamp hole while the other can be anchored to the rod via the head of a split pin that in turn fits a hole drilled in the rod. Just make sure that nothing can snag the front brake cable or lighting contro/horn lead.

Or you could just buy a ready made quick action throttle pulley. I must admit I like my throttle not to snap back it makes right hand signals easier.


So does an engine that doesn't die on shut off, with a tickover.

If you drop your bike on a right handler with the throttle stuck open & watch it screaming along on it's side, you might think differently. This has happened to me in traffic & when the rear wheel made contact with something, the bike relaunched itself. Fortunately nobody was harmed but it could have been so different......
Warkton Tornado No.1
 
Posts: 2112
Joined: Sun Jan 11, 2015 1:27 pm

Re: Series 3 lower headset rebuild on the bench

Postby jdevane5 » Sun Aug 15, 2021 12:06 pm

All sorted with the headset and working well.
Kept it all as stock throttle wise.

Cheers again for the pointers
JD
jdevane5
 
Posts: 107
Joined: Mon Oct 14, 2019 8:53 pm


Return to Series 1, 2 & 3

Who is online

Users browsing this forum: No registered users and 29 guests

cron