Frame adjustments LI to GP

[simplex]

Hi
I have at last found a frame that is already cut.. which saves the full frame sitting in the garage. but its an LI frame.. and I need to reduce the length of the fork tube on the frame to suit GP forks.. anybody done this succesfully and willing to share any helpful knowledge on how it was done..

Regards

[Knowledge]

any helpful knowledge ?

The problem with the fork tube is that before it is welded onto the frame tube, it is machined at the top to accept the top bearing race. When you cut the top inch off the fork tube, you also remove the machined section of the tube and the race no longer drops into the top of the fork tube. You can try to machine-down the OD of the top race, but it is very, very hard.

I got around this by using the chrome ring top bearing race, which has a smaller OD and is a very, very loose fit into the shortened tube. To make it fit, you have to machine a spacer to take up the slack. I used a knackered chrome ring. I cut the web off and machined it down until it became fit for purpose. Unlike the bearing race, the chrome ring is not hardened and machines easily, though it would not be difficult to make an adaptor from mild steel billet.

I hope this helps

[stafford]

Cut 25mil of the fork tube then have steering race machined to suit internal diameter also dont forget to move steering stop up over on the forks

[paulmgreen]

Cut the section out the frame using pipe cutter then reweld . Common race bike modification. Chalky at Replay scooter can do it for you

[rondon]

^^^as above^^^^

[RICSPEED]

as above but you can also use a jubilee clip round the headstock as a cutting guide as this will be square to the tube

[FREAK]

ive done this a few times ,its quite easy i always use a chrome ring cos it encorporates the steering lock cut 25mm off the tube then use an expanding reamer to open out the tube till the ring fits (tight) takes about 15 mins in total , then either use a chrome ring sx headset or cut 7mm off the bottom of an sx gp li etc hed set looks cool with the ring