LCGB Forums

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

Fork buffers

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

Fork buffers

Postby dickie » Thu Feb 13, 2020 5:42 pm

I'm at the early stages of assembling parts for a new build; LI150 special.

The forks will have bgm progressive springs and some dampers (undecided type).

So, which buffers? I read one thing and another about thick and thin, top and bottom, and how they affect ride height.

So far, I've just accepted this, but when I think about it critically, it doesn't make sense to me. Surely, I'm riding with my weight on the springs not the buffers, unless I'm very porky or me and the bike are massless.

This makes me think it should be thin on both top and bottom.

Thoughts?
dickie
 
Posts: 1258
Joined: Thu Oct 02, 2014 12:32 pm
Location: Tyne and Wear

Re: Fork buffers

Postby Warkton Tornado No.1 » Thu Feb 13, 2020 6:44 pm

My personal thoughts are that it is preferable to match every item within the fork assembly as closely as possible. The links in particular have faces top & bottom that make contact with the buffers, so they may require an amount of fettling to align.

As for the lower buffers, they surely can only be 'influential' upon the quality of the ride upon rebound. In my experience, that is likely to only be of concern in extremes, such as racing, where heavy braking only occurs prior to a corner, in which case it would be undesirable that they could influence how well the suspension affects the balance of the machine. Done correctly, with braking 'flowing' into the corner & keeping the suspension loaded whilst negotiating the corner, the rebound buffers would not be even touched by the fork links. Otherwise, the lower buffers are only active with the bike on the stand with no load.

Indeed, although I have experimented in the past with cut down lower buffers, there were racers that left them out entirely, but that may have been in conjunction with certain aftermarket dampers that may have obviated the need. (Before anybody gets the wrong idea, I'm not on about BGM etc, although there appear to be many users on this Forum that recommend their use)

As for the top buffers, if they come into play @ all, during extreme hard braking, then the front end will start to bounce, with a rapid series of lock ups/release/lock ups/release that can be quite controllable in a straight line on a dry surface & also an indicator that maximum braking is in operation as far as the suspension & tyres allow. This was a common occurrence when using the Cadwell Club circuit prior to entering the hairpin.

Obviously, in the case of anti-dive, then there may need to be different emphasis upon the roles of the buffers. As far as I am aware, there is no proof that anti-dive is any better than a conventional braking set up, but it appears to sell well, just as whip aerials did, once upon a time. I have known extremely good riders try anti-dive & taken it off, preferring the feel that dive gives them.

I hope this helps ;)
Warkton Tornado No.1
 
Posts: 1653
Joined: Sun Jan 11, 2015 1:27 pm

Re: Fork buffers

Postby dickie » Thu Feb 13, 2020 10:04 pm

Thanks mark, that's pretty much what I was thinking.

I'll probably just draw them on. Or use thin ones on top and bottom.
dickie
 
Posts: 1258
Joined: Thu Oct 02, 2014 12:32 pm
Location: Tyne and Wear

Re: Fork buffers

Postby landybretta » Fri Feb 14, 2020 10:31 am

When I rebuilt my LI 150 Special (185) I replaced the buffers as originally fitted, i.e. thin at the top and thick at the bottom.
I fitted progressive springs and added BGM non adjustable dampers, with a properly set up front drum brake.
Works a treat. All depends oh how you ride it I suppose.
User avatar
landybretta
 
Posts: 356
Joined: Thu Jun 05, 2014 10:22 pm

Re: Fork buffers

Postby HxPaul » Sat Feb 15, 2020 10:27 am

landybretta wrote:When I rebuilt my LI 150 Special (185) I replaced the buffers as originally fitted, i.e. thin at the top and thick at the bottom.
I fitted progressive springs and added BGM non adjustable dampers, with a properly set up front drum brake.
Works a treat. All depends oh how you ride it I suppose.

When I fit mine,I fitted thick ones top and bottom.
User avatar
HxPaul
 
Posts: 1545
Joined: Fri May 30, 2014 9:18 am
Location: Halifax


Return to Series 1, 2 & 3

Who is online

Users browsing this forum: barryham, Google [Bot] and 9 guests