series 3LIS forks front wheel out of line problem

[grumpar]

This ones got me beat after a extensive fork and wheel rebuild my front wheel is out of line i've had it together and apart 5 times and cant find any fault.
I have swapped the springs and rods and top hats over from side to side and it has not made any difference its still to one side (same side ) any ideas i don't see theirs any play with the hub. is there any spacers ever used around the top hats etc ?. I've never seen any

I am at home now for xmas so was going to have one more go with it before i get some other forks its been on hold since i abandoned it last summer.
Its a LIS150 drum brake i have had the damper brackets welded on the forks and the arms and powder coated and re-chromed by very reputable scooter restorers who we all use and there work is faultless.
https://flic.kr/p/q9YgbS

[CHRIS in MARGATE]

If the wheel spindle is true then you need to establish that the fork links are higher /lower one side or the other by getting the scooter perfectly level on level ground and measuring the distances of both fork links.
Have you changed the rebound rubbers and are they the same size?
It is practical and safe to add spacing washers to the tops of the rods to adjust because sometimes the top hats can sit higher/lower. It is not normal but it's not unusual.

[grumpar]

Hi what i have now is 9.25" one side and 9.5" the other a quarter of a inch this would be more, i have one of the metal plates from a old bump stop under the bump stop of the of the lowest link to raise it.
There's a new set of bump stops fitted big to the bottom and small to the to top double checked i thought that was the mistake when i first but it back together
would a bump stop problem correct itself when the weight of the bike was on them with the stand down.
I have reversed the springs and top hats and its the same so not tension on the springs ? is it worth changing.
I have the same measurement from the top hat stops inside the forks to the bottom at both sides.

[grandpa]

Hi grumpar,
Make sure the top hats are seating fully by tapping them in gently then measure.Assemble the fork links as per picture and check if they are square and equal. Check the depth of piston rod recess in each forklink to see if same. My fork links(Indian) needed grinding to square them up.

Grandpa

[grumpar]

Thanks Grandpa
will try that next i've got the forks out this afternoon and checked them from every angle and they all measure up ok so going for the links now

[grandpa]

Hi grumpar,
Forgot to mention that I would be inclined to assemble forks without springs and check for any binds caused by forklink bolts or bent piston rods
Grandpa

[grumpar]

Hi Will try that next ive had them apart and back together trying all combination last night 'ive swapped the springs top hats rods over and tried with and without the bump stops in all combinations and have a slight improvement i am down to 5mm now which i could correct with filing the lock nut down 2mm and adding a 2mm spacer to the other side but going to keep at it before that i would rather get it right

I've had a cross line laser on and all lines up except the links

[Wack]

When you say out of line , do you mean the wheel is tilted or the whole hub is off centre?

[monument7]

Probably a daft question but what was it like before you took it apart. Could have been assembled wrong previously

[grumpar]

When you say out of line , do you mean the wheel is tilted or the whole hub is off centre?

The links are out of line tilting the wheel.. i've depth tested the top hat seats , reversed the pistons and springs in all combinations tried with and without bump stops
i've even had the cross line laser on which gives me a plum and level line .

I did have the damper studs welded to the links and the forks were sent for the top damper brackets welding on which involved blasting and powder coat both done by very reputable lambretta builders

[grumpar]

Probably a daft question but what was it like before you took it apart. Could have been assembled wrong previously

I wonder this myself i never noticed anything wrong but to be honest i never looked ive probably only noticed because theirs no front mudguard on

[Wack]

Firstly I would remove the links then try to pass a 12mm round bar thru the pivot holes,if it wont go thru both fork boots then there may be a problem with one of the fork legs being bent .Then with some spacers ,bolt the links together and check the bump stop faces are level with each other,the axle eyes are level and parallel to the pivots and the inner faces of the axle eyes are vertical to each other.Very often you may find one link is twisted so you may need to tweek it a little to bend it back into line.If the links and forks check out then the only alternative may be to grind a little off the lower bump rubber on the higher side to let the link sit lower or you can file the axle washer on its outer edge about a 1/4 of the way around which allows it to sit higher in it's rebate lifting the axle up a fraction.

[grumpar]

SORTED i hope iv'e been in the garage for two and a half days now...... Thanks to your suggestions and help i think iv'e got it. I did the fixing the links together again and all measured up ok again then i noticed the links were slightly different one had the molding marks ground off the other didn't so not original pair i thought on closer looking one of the cups for the fixed ball ends on the damper rods was slightly deeper than the other so i put a 2mm washer between the damper and the spring to compensate perfect fit after a bit of filing put it all back together dropped the wheel in perfect spot on center.Who would have thought 2mm could throw the wheel so far out. I don't think the washer will cause any safety issues so its staying in there cheers all

[CHRIS in MARGATE]

Well done.. You stayed with it.. Just goes to show assumption is the mother of all evil. Not a matching pair of links: aghhh !