Posts
581
Joined
2/10/2014
Location
GB
Edited Date/Time
1/31/2021 4:03am
Hi guys , we started the build up of a 1983 'RC480' this week. It's been a bit crazy here the last few months so I haven't really had the chance to share some of the builds we have been working on.... But this one is gonna be TRICK, so I had to share it!
I don't really have any "before" pictures as it started out as just collection of parts.
Originally, the customer wanted a 1980 Twinshock CR480 so a 1983 CR480 motor was sourced and rebuilt. A 1980 CR250 frame was modified and the build up was ready to start.....
Then it turned out that a 1980 Twinshock CR480 wouldn't be eligible to race in any class in France, where the customer lives.
So we had to have a re-think...
We had a fully rebuilt '83 CR480 motor sat on the bench. We had a pair of fully rebuilt 1983 CR480 wheels and a pair of 1987 CR250 43mm forks already converted for the 83 drum brake.....
We also happened to have a really nice 1983 CR480 frame sat in storage.... So we came up with a new plan!! A 1982/83 RC480 replica!!
The frame was repaired, there were a few small dings in the bottom tubes. We added bash plate mounts and also modified the swingarm spindle area for a captive head spindle.
The customer wanted an "full on" build so an RC "coke bottle" swingarm, alloy tank and one piece alloy sub-frame and airbox was ordered from Bormi parts in Italy.
The swingarm and tank arrived back in the shop on Wednesday and we have started bolting it all together!
Here's some teaser pics from when we laid it all out before we began assembly. I'll post more pics up as we get further through the build up. It will be pretty quick this one,as we have pretty much everything we need in stock and ready to go!
Cheers
Stevie
I don't really have any "before" pictures as it started out as just collection of parts.
Originally, the customer wanted a 1980 Twinshock CR480 so a 1983 CR480 motor was sourced and rebuilt. A 1980 CR250 frame was modified and the build up was ready to start.....
Then it turned out that a 1980 Twinshock CR480 wouldn't be eligible to race in any class in France, where the customer lives.
So we had to have a re-think...
We had a fully rebuilt '83 CR480 motor sat on the bench. We had a pair of fully rebuilt 1983 CR480 wheels and a pair of 1987 CR250 43mm forks already converted for the 83 drum brake.....
We also happened to have a really nice 1983 CR480 frame sat in storage.... So we came up with a new plan!! A 1982/83 RC480 replica!!
The frame was repaired, there were a few small dings in the bottom tubes. We added bash plate mounts and also modified the swingarm spindle area for a captive head spindle.
The customer wanted an "full on" build so an RC "coke bottle" swingarm, alloy tank and one piece alloy sub-frame and airbox was ordered from Bormi parts in Italy.
The swingarm and tank arrived back in the shop on Wednesday and we have started bolting it all together!
Here's some teaser pics from when we laid it all out before we began assembly. I'll post more pics up as we get further through the build up. It will be pretty quick this one,as we have pretty much everything we need in stock and ready to go!
Cheers
Stevie
Can’t wait to see the updates. That swing arm is so sick, and the tank is badass too.
The clamps we make ourselves from 6082-T6 alloy. They move the bars further forward and raise them a little. This gives a massive improvement in ergonomics. It gives these older bike a completely "modern" feel.
Titanium stem top nut and bearing adjuster nut. (Made in house) and one of our HRC spec front #plate bolts.
Fitted the new linkage up as well. This is the first, prototype, CR480 linkage assembly we have made. Billet 7075-T6 for the link and 6082-T6 for the knuckle. The link is longer than stock. The same length as a "Simons" link. This gives a much more modern and progressive linkage ratio. It also has proper bearings!! The stock 480 linkage used bushes! We are using a modified 1988 CR250 bearing set, plus a pair of seals whipped out of an 89 kit, plus CRF450 lower shock bearing. (We have the seals from the 89 kits on order so we don't have to canibalise kits in the future!!)
As the link is longer than the original it requires the front mounting point to moved forward. Plus some special, offset, collar bushes to be machined and fitting into the frame. I'll get some detail pics of 'before and after' this mod, showing how it's been done.
All the bolts are Titanium, made in house. All with period correct HRC hexagon sizes and shape.
The customer requested the Ohlins shock.
The pics will come quickly next week, its moved a little further on since i took these! I'll get updates during the week.
Hopefully, she'll be on her wheels and rolling by Wednesday
Stevie
The Shop
This is my favourite part of the build so far. The swingarm spindle is Titanium. (Made in house. Heat treated and shot peened) We modified the frame so the head is captive. This was done on the factory bikes of the time but it didn't reach production bikes till '88!
Titanium bolts through out.
Titanium bearing adjuster nut and stem top nut.
Adjustable billet brake trq arm.
I'll get some more detail pics in the next few days once it's fully rolling.
Stevie
Absolutely brilliant execution sparing nothing.
I would be greatly indebted to know if one wanted something similar what to expect roughly cost wise and already having a host bike.
Over $30,000.00?
Even more impressive if he intends to ride this regularly.
Great post for guys who dream of being able to craft at this level.
He already has one our our 1980 CR250's and originally wanted a 480 version to "match". Sadly there is no class for them in France. As we had already done the motor, wheels and forks, (we had a 1980 frame modified as well, but we will be using that on another build instead) it was pretty easy to swap it all over to an 83 RC480 build.
When someone asks for a build like this it actually makes it way easier for me. I don't like it when I have to compromise, and I can just get on and build it exactly how I want to! ?
Although, on the this one the motor is virtually standard. We make gear sets and billet clutch baskets for the 480, but they haven't been fitted.
The squish has been recut to stop detention. We also remove the cylinder head studs and use bolts, there are steel inserts in the barrel so the threads don't get distroyed! We also add dowels so the head locates accurately.
When the 480 motor is fitted on to the 1980 chassis you can't take the top end off with the motor in the frame when the head studs are left in... It's a real pain in the ass! Swapping to bolts gets around that. This had already been done before the change to a STD 83 480 frame.
You can see how much further forward the the new link mounts
The offset collars we brazed into the frame for the new mount. We made them so they have the same outer width as the original mounting point, so the original bolt can be used.
Pit Row
Oh my god!! I can't wait to get this fitted up!! We can finish the exhaust system up with the sub frame fitted then.... it's first start up time!! ?????
Why shot peen and heat treat the titanium? I would of guessed it would of been strong enough?
Sweet build and props for the craftmanship
I managed to get the sub-frame/airbox bolted up yesterday, and made a start on the pipe, once the pipes sorted were gonna fire her up! Then the tank and airbox assembly can go out for paint
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