Highbrid Yamaha - The TZ bit
I posted the image above in closing weeks of 2017 on twitter to thank some sponsors and more importantly; to introduce my next stage of this project...
...Enter the Yamaha TZ chassis.
Mounting the engine
I have already spoken in depth about the engine in another blog entry so I wont dwell on the hows and whys here. I didn't have a TZ engine for my TZ chassis so the RD lump, in whatever guise it found itself, was going in this chassis. To make this work, some fabricating and welding of brackets would be required and seeing as Andy Green had the exact same plan with one of his TZ chassis, we decided to do the job together at his garage.
The RD***LC engine cases we were using would fit the front engine mounts with simple spacers, the back is the area we are interested in. The TZ rear mount is far too small and in the wrong place so we lopped them off (we are working two cassis remember) and cleaned the area up for welding.
Some wide box section was then cut to a short length then split in half to give us two short U shapes.
These were then profiled on their stubby little arms, taking care to keep things square, to match the chassis and the long flat edge had two channels cut into it to match two hollow dowels witch were cut to match the length of the rear engine mount points.
Once things were tidied up from fabricating Andy Mig welded the dowels to the U shaped bracket. This assembly was then offered up to the chassis with a set of cases carefully positioned in the right place. When we were satisfied with the location, the new bracket assembly was tacked, rechecked then fully mig welded into place.
Whilst Andy got to welding on the two TZ chassis; I got to fabricating some rear engine mount brackets. These were, as far as possible made identical so we had interchangeability and spares in case we managed to crack one.
The end result is a set of RD***LC cases hanging perfectly in a TZ chassis. One massive hurdle overcome.
Getting the chassis rolling
The Front
I was going to use as much of last years bike as was needed to keep costs down and frankly it was a good bike so why wouldn't I?
The front end is basically a bolt in item. If you have an RD front end with "race" altered steering locks, it will go in a TZ chassis with no fuss.
I didn't fit head race bearings right away as I wanted to paint the chassis first. This would wait till the bike was built though as sods law says you will need to weld or drill something, ruining your work. In the end I dropped some taper bearings in which were no fuss after spending a week in the freezer.
Later on I made some adjustments to the steering lock. The steering lock on the headstock was a bolt on bit of plate which was too short for my bottom yolk to contact before it hit things it shouldn't. I made a larger plate with the same bolt holes and profiled it down till the clipons just cleared the instruments.
Later on I made some adjustments to the steering lock. The steering lock on the headstock was a bolt on bit of plate which was too short for my bottom yolk to contact before it hit things it shouldn't. I made a larger plate with the same bolt holes and profiled it down till the clipons just cleared the instruments.
The Back
Getting the back in is far less straight forward.
The spindle size is much bigger at 20mm so all the old spacers were not only the wrong length but also bore.
TZ chain adjusters are silly money as they have the letters T and Z in their name so I opted to drill out my existing chain adjuster like the cheapskate that I am. This worked great and coupled with a random spindle I had lying about and the old TZ spacers that came with my wheels, I could now at least roll the bike about the garage when I needed to.
The spindle was a touch on the long side and the idea of that thing slapping about would probably not end well pushing the bike far enough let alone riding the thing. A suitable amount of exposed tube was marked for thread length and the the rest was chopped off. Now the exposed end was chamfered and threaded. Simple as that and an n'th of the price of a TZ item.
Next up, thanks to the way the Astra-lite wheels had been setup, was spacers. these were machined up in much the same fasion as the ones for the RD chassis: Some 30mm Aluminium bar was cut to drilled for a 20mm ID and one end machined down to sit inside the wheel bearing meeting the internal spacer for length. The bar was then cut to give the correct length of unmachined spacer and the process repeated for the other side.
Everything was test assembled and all was well so the Rear brake bracket was next on the list. I used the one from last year as it had done the job perfectly. All that was required to make this fit was a step to be cut into the outside of the OB spacer for it to sit on. The tie bar was then remade longer to meet the existing tie bar lug on the swing arm and suddenly things looked very much like they were done!
The spindle was a touch on the long side and the idea of that thing slapping about would probably not end well pushing the bike far enough let alone riding the thing. A suitable amount of exposed tube was marked for thread length and the the rest was chopped off. Now the exposed end was chamfered and threaded. Simple as that and an n'th of the price of a TZ item.Next up, thanks to the way the Astra-lite wheels had been setup, was spacers. these were machined up in much the same fasion as the ones for the RD chassis: Some 30mm Aluminium bar was cut to drilled for a 20mm ID and one end machined down to sit inside the wheel bearing meeting the internal spacer for length. The bar was then cut to give the correct length of unmachined spacer and the process repeated for the other side.
Everything was test assembled and all was well so the Rear brake bracket was next on the list. I used the one from last year as it had done the job perfectly. All that was required to make this fit was a step to be cut into the outside of the OB spacer for it to sit on. The tie bar was then remade longer to meet the existing tie bar lug on the swing arm and suddenly things looked very much like they were done! A moments distraction
During this work Andy Green popped round to take back something that has been in the background of many of my images.
This Yamaha RD250 YPVS was loaned to me at the end of 2015 as a planned build to get me into racing. Work and other distractions prevented this getting much further than some light chassis work and spacer making before the RD250 D was offered to me. This bike is going back to its owner now as the RGV250 VJ21 front end is needed for another project.
I'm sure we haven't seen the last of this bike but at least now it will stop teasing me from the corner of my garage.
Accessorising
The bike was in need of a few nicetied that were missing from the largely original swing arm.
ACU rules neccesetate the fitting of a sharks fin to reduce the chance of a marcial sticking his pinkies where they would get into bother (within reason and only on this bike I can't stop them getting themselves into bother in the bar or the back of a van).
Bits for the back end
The RD had a tubular swing arm so P-clips worked great for this job but the rectangular box section of this swing arm was going to need something welding to it. 
I opted for a tab that could be drilled to accept a bolted on sharks fin so if it got damaged in a spill, a new one could be bolted on. The tab was made from some split and shaped box section that was welded on with my R-tech Digital 170 with surprisingly little drama considering the age of the chassis.
Whilst I was there; a pair of long M8 nuts were also welded on so some off the shelf aluminium bobbins could be bolted on.
I could have gone for the old school bar through the spindle look and saved a few grams but these are much quicker and easier for a busy paddock.
As it happened this would not work out as the exhausts get in the way of the bobbins so I went and bought some 10mm bar. This worked till I hit ground clearance issues at Pembrey. Pushing the exhaust up now covered the spindle hole so I now use the pegs for the paddock stand.
This was all a bit reactive for my liking but with the VFR build going along side this and time wearing on, I just had to get on with it. New exhausts will eventually allow me to use these bobbins again.
This was all a bit reactive for my liking but with the VFR build going along side this and time wearing on, I just had to get on with it. New exhausts will eventually allow me to use these bobbins again.
The sharks fin might look familiar and for very good reason as it is also off of the old bike.
This would also need a little alteration. The space to fit the sharks fin and bobbins was very tight so I decided to simply 'reshape' the sharks fin to suit my situation.
Being aluminium, this was very quick and easy to do whilst still looking smart.
Some time with spray cans was going to be needed soon as I had done a lot of work but things still looked rather ropy to say the least!
Exhausts
at the end of 2017 I had crazy ideas of making new exhaust but the purchase of the VFR750 RC24 quickly put that plan to bed.
As I had the engine test fitted in the chassis I tried slinging on my TZ250 G expansion chambers to check clearences.
The fit was great (who would have thought TZ exhaust would fit a TZ chassis better than an RD?) so with the springs holding the pipes in places I could line up where the rear mounts would need to go.
The correct mounts, as pictured on the right, are however a touch on the expensive side. I knew I could make something similar for next to nothing, I had done it before afterall.I initially made two steel plates witch were bolted together with a tap washer bolted in the middle to act as a dampener for each expansion chamber. This would act just like the original however the angle is adjustable; allowing me to move things about a bit easier.
These were moved about and changed to meet the needs of either side exhaust before being all but binned for clearance reasons. The left ended up with an aluminium arm with a rubber cushion and the right used one of the steel plates and its washer which did the job in the end.Fairing brackets
Another thing I intended to reuse was the fairing. Luckily being a TZ250 C/D/E fairing; it was basically designed for this chassis.
Test fitting showed this to be an unsurprising good match.
The screen bracket fit the headstock nut and married up to the screen nicely so that one was done for now.
The seat unit was just two bolt holes off being a bolt on so that just left the back of the side fairings to sort.
I had previously used the aft upper engine mount as the pivot point for a bracket on the AC engine but on the LC engine I was using it to stop the lump from falling out.
Two convenient lugs at the rear of the chassis are provided for two short fairing brackets so I decided to stick to my current stainless tube but move the ally brackets to a slightly wider stanced home.
With the fairing and bracket fitted; I picked up the holes with a scribe. The bracket was then removed and ally brackets taken to the shed to be reworked. I drilled out the new holes, check fitted them and then re profiled them to look tidier. Easy!
I might replace these with smaller Aluminium brackets one day but I don't think that weight loss will be the thing that gives me the edge I need.
The front Instrument cluster bracket and fairing stay was also reused. This was the right lenght but the mounting point was wider on th TZ chassis.
At first I planned to drill some 20mm bar to allow the 17mm tube stay to slip in but for the small difference that was required I just ran a couple of beads round it with the welder instead. This worked just fine allowing me to drill a slightly lower hole in the fairing and get on with some-thing else.
It was getting rather late in the game when it became very clear that my TZ tank wasn't going to be made in time for Pembrey.
Andy Green yet again came to the rescue with a spare he had for another project.
This bolted on with only a little arguing from the headstock bearing cover which fouls a seam on the tank but was otherwise a fantastic fit.
The big drawback of this big tank was that it now fowls the upper fairing stay.
The 10mm bar I had recently bought for a paddock stand job came in handy as I quickly joggled a new bracket out and welded on a flat tab. All my time welding up the VFR750 RC24's exhaust was clearly paying off as this was far less of a faf compared to previous efforts.
The tank itself is a wonderful item produced my Peter Kyte of:
Custom Tanks & Designs
Unit 23a Pershore Trading Estate
Pershore Worcestershire WR10 2DD
United Kingdom
The tank itself is held on at the front with rubber pucks and the rear by a strap. Some people use hoover belts but the genuine thing is a tenner and does look a lot smarter. All I needed to do was use a bracket on the seat unit to clip the strap onto. The genuine one is about £15 but I had plenty of metal which was free and you weren't going to see it anyway.
I used the old seat bracket from the RD chassis which had already got the bolt holes drilled in it. All I had to do was cut it down till it just met the tank then joggled the end down to act as a hook.
With the fairing and bracket fitted; I picked up the holes with a scribe. The bracket was then removed and ally brackets taken to the shed to be reworked. I drilled out the new holes, check fitted them and then re profiled them to look tidier. Easy!
I might replace these with smaller Aluminium brackets one day but I don't think that weight loss will be the thing that gives me the edge I need.
The front Instrument cluster bracket and fairing stay was also reused. This was the right lenght but the mounting point was wider on th TZ chassis.
At first I planned to drill some 20mm bar to allow the 17mm tube stay to slip in but for the small difference that was required I just ran a couple of beads round it with the welder instead. This worked just fine allowing me to drill a slightly lower hole in the fairing and get on with some-thing else.
Andy Green yet again came to the rescue with a spare he had for another project.
This bolted on with only a little arguing from the headstock bearing cover which fouls a seam on the tank but was otherwise a fantastic fit.
The big drawback of this big tank was that it now fowls the upper fairing stay.The 10mm bar I had recently bought for a paddock stand job came in handy as I quickly joggled a new bracket out and welded on a flat tab. All my time welding up the VFR750 RC24's exhaust was clearly paying off as this was far less of a faf compared to previous efforts.
The tank itself is a wonderful item produced my Peter Kyte of:
Custom Tanks & Designs
Unit 23a Pershore Trading Estate
Pershore Worcestershire WR10 2DD
United Kingdom
Tank strap
The tank itself is held on at the front with rubber pucks and the rear by a strap. Some people use hoover belts but the genuine thing is a tenner and does look a lot smarter. All I needed to do was use a bracket on the seat unit to clip the strap onto. The genuine one is about £15 but I had plenty of metal which was free and you weren't going to see it anyway.
I used the old seat bracket from the RD chassis which had already got the bolt holes drilled in it. All I had to do was cut it down till it just met the tank then joggled the end down to act as a hook.
Plumbing
Following on from fitting the tank nicely, I got the plumbing sorted for the fuel system.
The 1>2 branched system I had from the RD went in the bin as this tank had two separate lines.
Rather than taps, I just used some 1/4 BSP threaded hose fittings, 8mm hose and quick disconnect couplings.
These were all held together with genuine jubilee clips all supplied from Sleaford based Kiowa Ltd who were very helpful indeed.Wiring
Not strictly part of the chassis: I had to get the wiring and accessories on in-order to figure out what I did and didn't want on this chassis.
The front stay went on with all of its cockpit and battery bits from last year with little change.
Whist here I used polyurethane adhesive to repair my Koso EGT gauge which had suffered badly with the RD's vibrations, breaking all of its mounts.
Next I ran all of the wiring through holes in the chassis to the spine of the bike.
Everything was connected up and loosely rooted so that it would follow chassis tube lines and not interfere with the rear shock which runs up the middle of the bike.The coil packs fit nicely under the tank on the original TZ brackets but I was unable to figure out where the ignition units were supposed to go. In the end I tie wrapped them just behind the coil packs which, with the tank on, will be nice and tidy.
EGT and TTO sensors were straightforward bolt ons with the wiring just rooted so it was out of the way.
Some new crimps were needed here and there to allow for the things being in different places and damage. I backed up each crimp with solder to prevent the wires from working loose.
Once I was happy with final locations for everything I tie wrapped everything to the frame to keep it tidy and prevent it touching things it shouldn't be touching.
Finishing up
If you hadn't noticed already, this all took quite a long time. Along side it's bigger stable mate, this project was ongoing up to about 2 hours before the start of practice at Pembrey!I had hopes of building the bike up, stripping it and repainting the chassis before a final build. As the VFR build dragged on I had to hurriedly build this bike up which presented a number of other problems. The time saved in not stripping the bike was quickly eaten up by "finding things" that I had loosely assembled or used alternative fasteners for mock-up purposes.
Smaller bolts, wing nuts and other such temporary things were swapped out in succession till the bike started to look a bit more solid and together.
I had little time for photography or note taking as the nights got late and the van needed packing.
Luckily On the day, things went extremely well. The bike outperformed my expectations and thankfully didn't fall apart immediately.
There will be plenty of things to tinker with in the future before I can say the bike is finished (is a bike ever finished?) but for now; the TRD250 is looking pretty sorted.
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