Yamaha (mk2)

You know how you sort of collect stuff, well the shed is filling up again so I thought it was about time I got another project under way.
Something low, comfortable and practical this time.

XS11 frame
VF forks and 16" wheel

A Sierra diff
Oops! better put that back together some time.

I've also got a pair of wide(ish) glide ally slab yokes, There's a quickbob tank somewhere, and those old 14" Compomotive wheels are just ripe for restoration. I've gained a Goldwing King & Queen seat
Trouble with the yokes is that they don't fit the VF 39mm fork legs or the Yamaha headstock. So they need boring out and converting. I had a bit of luck and bought a small boring head for 15 at the Netley Marsh Steam Rally. I borrowed a vertical slide from Bruce (Arrowhead) and made a mounting to fit it to the saddle of my Chester lathe. After a lot of fiddling about I finally managed to bore out the top yoke.

Oh for a vertical mill.
I'm dead chuffed with that finish!.

Laser precision.
Suspension mounts
Rear view
A top box!
Front threequarter

A set of wishbones and hub carriers have been puchased from MK who make the IndyBlade kit car. This is a Lotus Seven lookalike with a Honda Fireblade engine in it. I've seen pictures of one with two ZX10 motors!!
I've had the Compomotive wheels rebuilt. I had to make the new O-ring seals as Compomotive couldn't supply them. Alloy Magic did the repaint and polished the rims. A pair of new BF Goodrich 265/50/14 Radial T/As should keep the frame from dragging on the road at the back.
A Ford Sierra diff, driveshafts and brakes were stripped from a scrapper (on the day I found out my job was going down the pan - nice timing). The driveshafts have been shortened to suit (see Techstuff).
The Quickbob tank has been widened by 4 1/2 inches and a new fuel takeoff point brazed in.
The Sigma seat has been dumped in favour of a stepped seat.
Clive has spent many hours in his garage, pushing his mill to the limits, milling up a new fork brace
Oh yes, the topbox - mmm! Well I thought that as the wishbones were going to get in the way of panniers or saddlebags I needed something else (well it is supposed to be a bit practical). While rooting around at R&T Motorcycles one day I found the box from an XVZ-12. No I don't know what that is either, It was supplied by a dealer in Texas so I assume it was from an import. I seem to remember back in the eighties Yamaha built a big tourer to take on the Honda Goldwing. I have since discovered that the topbox is from a Yamaha Venturer which was a V-Max in a touring suit.
I took a trip up to the National Kit Car Show, spent a fortune on tools and had a good look at various bits and bobs. I came across the Z Cars stand where I spotted a couple of Mini bodyshells with Bike engines stuffed in the back. Have a look at their website (link on links page). I got talking to Chris Allanson the director about an anti-roll bar for my Trike. I sent him the design on Tuesday and had the ARB on Friday. What service!
Another firm I contacted about anti-roll bars had none in stock and haven't come back to me after 6 weeks. I had some wheel nuts on order for 2 months - I sometimes think that firms don't actually want my money.
I sprayed the Trike myself. I got hold of a compressor and started spraying, after all how hard can it be? Bloody hard!! It's easy enough to lay paint on but trying to get a finish is another thing. I had a rolling chassis with engine ready to go to the motorcycle world exhibition at Beaulieu at the end of June.

Hiding away in the corner of the custom tent

Once at this stage I didn't think I had far to go - wrong! Exhaust, mudguards, wiring, handbrake, all took ages or were far more complicated than I thought they'd be.

My apprentice

Although it's on the road now there are still things I want to do to it, fit a new diff (3.14 as opposed to 3.36:1) to improve the fuel consumption and a fog light.

Ogri Rally
Mag Show

I managed to get to the Ogri rally and the MAG ride in show at Eastleigh, not a lot out of a summer, but hey! I got my Trike on the road.

I've got a higher ratio diff now from a scrappy. I was having a real struggle to get it out until a guy came wandering through the yard looking for bits for his car. We got chatting and he stayed and gave me a hand, so a big thanks to Rob - not a Biker but the right attitude. You never know I might have made a convert.

In order that thye Trike goes in the right direction the differential was fitted upside down. The gears in most modern differentials are hypoid, which means they are cut to run mainly in one direction and pull themselves into mesh. Which is why when you drive your car quickly in reverse it whines. Imagine that whine happening while going forwards and that's what you end up with. Besides that, the gears would wear out quickly because they would be running on the 'coast' side of the gear. Which also makes the gears try to push away from the thrust bearing and out of the housing.
This means the "new" diff had to be fitted the correct way up. So now the Trike will go backwards or I have to reverse the direction of rotation of the propshaft. Investigation of the Yamaha middle gearbox showed that reversing the bevel gears was not a simple option as the casting is waisted and a whole new complicated housing is needed. I decided to build a reverse rotation gearbox. Trawling through my collection of strategic spares (or junk as my SO puts it) I came up with two Yam 1100 1st gears, the splined output shaft from a middle gearbox and various reliant propshaft bits.

The gears were bushed and welded to the splined shaft, sealed bearings fitted ('cos they were free). A casing was made from a "sandwich" of 3/4 alloy plate, two plates machined to take the bearings and one milled out to provide a distance piece. Seal holders and covers for the shaft ends were machined from solid. The shafts were left long as the contained the original centres and I didn't want to lose them.


The pictures above show the gears and bearings in place, also the slots that were milled in the sideplates to act as an oil resevoir. The drive flange is Yamaha, the splined shaft is Reliant onto which the Reliant sliding spline/UJ fits. An adaptor plate was made to go between the diff and this new gearbox. The original Yam propshaft was cut and a Reliant propshaft flange bushed and welded to the end.
I've put a .PDF on the site with some dimensions and further explanation.

I've only done a few mile so far, there is a lot less noise and gearchanges are smoother. Only time will tell if all the work has been worthwhile.

I must admit, converting the middle gearbox does appeal as a project, watch this space.

Well I decided the right way to do the job was to convert the middle gear box so the output rotation is reversed.
Basically the driver gear had to be moved from one end of the shaft to the other. The driven gear remained as standard.
The driver was pressed off its splines and bored out. The splines and inner end bearing diameter were ground down and a make up bush machined from steel The bush was shrunk onto the shaft and welded, the gear was shrunk onto the bush and also welded. A long spacer was made to obtain the correct position for the outer bearing as it's location has now been ground away.

driver gear shaft

The top shaft is the original the bottom has had the gear repositioned and the bearings reassembled on the shaft.

The middle gear casing had to be bored out so the driver gear would fit.

Oh dear!
finished hole

Unfortunately Yamaha have waisted the casting, so as I bored the tool broke through! The hole was filled with a plate "welded" in with Lumiweld.
The gears were blued and shimmed to acheive reasonable backlash and the whole issue bolted back onto the Trike, a new Yamaha/Sierra propshaft was made

I've only done a test around the block so far but everything seems OK