Steffs xs#1... Rake and stretch

[Prof]

Steff sent down his xs frame to be chopped. He included his 8" over forks and a set of tapered roller bearings and a few other bits including mudguard he plans to use. Sorry about the poor quality pics. The camera I have used does not like lights behind the subject.

Up on the jig ready for action...


A number of long phone calls and pms established basically what Steff wanted, so after a couple of final calls, today was the day to begin...

Don got into the action with the angle grinders and started removing unnecessary metal work...


Backbone heated at the bend and headstem is pulled up about 4". Then we put in the triple trees forks and a front wheel so the rake can be set up to allow the chopper to sit level with 4.5" ground clearance. When doing this we need to allow some estra height to allow for about 3/4" drop once the bike is complete and resting on the springs.


A phone call to clarify tank to be used (sporty) and tunnel depth and we decide to clear away all the gusseting and extra tubing to clean up the headstem area. We will replace all this ugly metal work with something tidy and flowing...


We'll put in two completely new down 28mm tubes to match the bottom tube. A couple of slugs are turned up to join things down at the engine mounts. They are chamfered one the bottom end as the frame tube on the bike is flattened and out of round and they will need to be hammered in with heat.


EAch bottom tube has been heated to cherry red and the slugs hammered in... tight and round...


A pair of down tubes are bent up (28mm x 2mm wall) and cut to rough length and set in. Much tidier.


Rake ends up at 42 degrees and axle to headstem centre distance is 590mm (40mm over the regs), but I was told not to be too worried about that. Once the seat rails are lowered and the seating position moved back about 4" with the high headstem this is going to be one nice cruising chopper! The rider will be nicely tucked down into the machine especially as she is all of 5'2"... one reason we are going low with the seating.

Next job will be to do the final shaping of the down tubes where they meet the steering head. Then we'll remove the front end and set up the laser and plumbline to get every thing hunkydory.

After that we'll get into the back end and completely rebuild it from the centre post back... with a couple of twists that Steff thinks will be just the ticket.

[Silent Grey Fellow]

Great job your doing there mate, that is going to be one hell of a good looking chopper when it's finished.

[Prof]

After taking up the mornign with phone calls, emails and ordering, we are back onto the xs this afternoon...
Downtubes were cut and bent last night...


Now being shaped for final fitting here getting bottom ends squared on linishing machine...


Drilled ready for plug welding...


Takes time to get a close fit on the back of the headstem... many trips between frame and grinder!


Meanwhile... give Steve a recipro saw and this is what he gets up to! Good thing we didn't need that bit mate!!! Not much left that's original...


Final check on fit and correct rake...


Now to get it all lined up... apply heat and twist with a big stillson so that...


Steering head is centred...


... and aligned... laser shows it is spot on. It will move around a bit as we weld and will need checking...


This fillet has been measured off a carboard template. It fits between the downtubes under the head stem. Always work off a centre line. A used cutting blade gives a nice curve, here being marked with my knife.


A second short tube will run similar to the stock frame, but curves down to near the bottom of the fillet. The slug will lock it to the fillet...


Lined up and bronze welded... a bit tricky to align so used bronze as it could be softened with heat for minor adjustments...


Fillet and secondary tube tacked in place...


Here's another shot that includes a cardboard pattern of a planned gusset linking all components of steering head area,

[Silent Grey Fellow]

Fantastic idea putting that gusset in there

[dg6oo2]

Excellent frame build you make it seem so easy.

[Prof]

Lots of ways to approach it, main thing is to take the time, look at making things flow nicely and make sure stresses are taken care of... extended forks increase stresses on backbone and steering head area so must be welded well and gusseted/triangulated suitablly... a bit of overkill is always a good thing.

A curved piece of tube as I have done here will tend to flex whereas a straight one won't. However to compensate for that tendency I have used 25mm instead of 20mm tube and it is also heavy wall rather than the thin original.

Although slender, the top fillet/gusset will help tie everything together .

Work has begun on the rear subframe today, but a number of interuptions slowed the process, so I wil put some pics up when I get a bit more done... but it is coming together nicely.

[Aussiehard]

I thought a single gusset was a bad idea, as it created stresses. It needs to be a gusset to each side of the tube???? I have seen many customs with single though…. Just something I remember reading.

[Prof]

Good comment Aussiehard.

From what I have read, what you are suggesting is generally preferable and is what I do in most cases. Where a single gusset is welded to the centre of the tube, stress is transfered to the centre which has less resistance than an edge and this can lead to a crack, whereas gussets mounted to the side of the tube spread the stesses.

In this particular case, the stresses from the headstem should be handled by the second tube under the backbone. The gusset I am using here is mainly to tie all the parts together and also for looks, particularly the tank sits on the backbone at an angle that I am continuing with the gusset.