Lambretta front end: dive, buffers, and fork links
This is a basic issue: the better your front brakes are, the more the scooter dives. It's an old design. Here are a few LCGB posts relating to this issue, and the removal/re-assembly of the various parts.
I have an orginal disk set up on GP200 with heavy duty springs and new Sebac shocks. The problem is when the brakes are applied the bike nose dives. Has anyone tried to solve this problem and if so how. It is only going to get worse when the hydraulic setup is put on.
Try Taffspeed front fork springs and four large fork buffers instead of two large two small buffers if you want an OK ride. Then try Taffspeed fork springs and double thick fork stops. The front will be so stiff it will be almost unridable. But no frontend dive.
I've just spent all morning wrestling the links out of my forks (1985 Indian GP125). Upon re-assembly (when paint is newly done) how the heck do I go about not damaging anything? The manual says can be done without the compressor tool but I'm dreading this part of the job!
Also, how do the new rubber bushes go in? The old ones were tough enough to get OUT while the links were in place... getting new ones IN is surely impossible... or am I missing something?
Talk about co-incidence!! I have just spent the last hour trying to get my links out and can't! I have tried the using the box spanner etc to compress and then I am assuming the ball that should be able to be removed is the ball end of the spring rod? So why wont mine come out :-(
I am also assuming that there should be a rubber buffer below the link? Well all I have is a mass of melted/pounded rubber, probably original from the factory!!
I am trying to do all this with forks still on the scoot. Am I going to have to remove the forks to do all this properly?????
There's no easy answer to this one. You could get a dealer to rebuild them but there's still no guarantee they'll not mark your new paint. I use a compressor tool and try to protect the fork coating with rags. Having an extra set of hands always helps to when it comes to poking the new bottom bush in. By the way - smallest bush goes in last. No your not missing anything - it may be a simple design but its a right pig to do on your own!!!
As the previous answer said, cover your forks in as much rag as you can but still allowing access to the bits. You can do this without a fork compressor but you need a good heavy vice. Turn them upside down and use a 15mm ring spanner for compression. They are not as hard as you think to put back together, trust me the taking apart is the hard bit.
While yes the smallest bush does go in last, I have tended to fit large all round for a few years now, you would be surprised how well the makes the front end more solid.
Right, finally got one of my fork links, springs, buffers out!! Now, the bottom one was completely knackered, no rubber left on it at all and the upper has a large split so obviously they are going to need replacing. I haven't done the other side yet because I have just realised upon reading the manual that I have the earlier type not the later type links!!! i.e. the ones where I need the compressing tool!!
OK, once I buy a compressing tool or borrow one from one of the lads if they have one, I need to move onto buying new buffers, etc. So, are there any recommendations here for buffers? There appears to be a choice of large or small and I have as yet no clue as to what difference that they would make to ride quality and handling, can anyone advise? Just in case it makes a difference, I am running a Series 2 Li 125 upped to a not yet run in 175.
I also note from the manual and from some web diagrams that there is a top fork bush, but I haven't been able to get at it, is there some trick to this? If it needs replacing should I go for the double thickness one for improved handling?
One last thing for now, what about the spring? I definitely need to replace the fork piston rod as its now bent but what of the spring? It looks almost completely compressed with less than a 2-3 millimeter gap, does this sound right to you lot??
Just to spell it out: Correct buffer fitment is large at the top, small at the bottom. Some use 2 6mm bolts, some don't, so 4 types to choose from. Some people fit large buffer at the bottom to stiffen up the suspension a bit, more spring pre-load.
Your fork rod can be bent back to shape they are quite a soft alloy (or mine have been), it only acts as a guide for the spring. You wont be the first or last to bend one. I was advised by a renowned dealer that the springs rarely need changing and by adding a extra top bush will beef them up a bit. If the bush is stuck try fishing it out with a wire coat hanger. I have not had any experience with using only large buffers, but it must make it harder to reassemble?. By reading your tales of wow you don't sound like you need any more hassles.
One of the greatest helps with this exercise is to have the forks removed and securely clamped in a sturdy vice. Doing the job in the machine is awkward. The top hats at the top of the springs can also be removed with a bent over thick wire as found on a black builders bucket handle. For the sake of less than �20 replace the springs with heavy duty items, which themselves go soggy after a surprisingly short time. As stated by previous, the rods are easily bent and easily straightened.
The compression tool will help but many have succeeded without, with a little ingenuity. Lots of clean grease and paper towels help!! You're nearly there.