CR250 Red Rocket swingarms!! About to start makin' chips!!

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9/20/2018 5:08 AM

Well, here it is!!!

It's taken a lot of work and lots of tweaking to get the design finished, but here she is:- the finalised CAD designs for our 1978-80 CR 250 swing arm!!

We have checked, double checked and triple checked every detail to make sure that we produce the finest quality swingarm possible, not something just thrown together from some "off the shelf" box section!!

The rear axle blocks /shock mount sections on each side will be machined from one piece, to ensure correct alignment of the axle, shock mounts and chain guide.

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The "legs" and centre box section will be CNC lazer cut and bent to ensure dimensional consistency and a perfect fit.
The legs are 2 halves, a top and bottom section. The weld bead will run horizontally from the the axle block up to the front pivot.
**The vertical line just in front of the shock mounts is just the bend line that's shown**

These arms will be 2" longer than the stock 1979 'arms. Through our intensive testing, we have found this to be the perfect length to provide a great improvment in handling and stability.
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We are planning on suppyling them as a "kit," complete with new lower shock bolts, rear axle and spacers, the bearing kit and, maybe, a chain guide (we've yet to finalise this though).

We will be starting on production of the prototype at the end of the month.

We are aiming for a retail price of around £900 (GB pounds). If you would like one then please call us! The more commited buyers there are, the easier it for us to justify a larger batch!

Call +44 (0)1492 641345
Or email info@phildentonengineering.com

Stevie

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Check out our website! www.phildentonengineering.com E-mail if you don't see what you're after!

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9/20/2018 8:16 AM

Good luck with the project. I think it is good to say “I can make that” and do so.

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9/20/2018 1:50 PM

If the swing arm is longer does that not make the suspension softer?

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9/20/2018 2:27 PM

Robgvx wrote:

If the swing arm is longer does that not make the suspension softer?

I think that would depend on the shock leverage relative to stock, but certainly the suspension could be adjusted to suit. Many of the aftermarket arms were longer back in the day, and I believe the 80 stock swingarm itself is two inches longer than the stock 78-79.

In on an arm for sure.

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Twitter: @ftemoto
Instagram: @mstusiak

9/21/2018 12:01 AM

Put me on the list please, Stevie!

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9/21/2018 1:30 AM

Stock chain roller or will we need to buy yours? Photo

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9/21/2018 1:32 AM

Hi Stevie,

If I read your description correctly, the swingarm will have a weld line up the side like the old factory RC swingarms? If that is the case, I may need to get on your list for your first batch.

2" longer is a lot. It should make the bike more stable but can slow down the steering a bit when you lay the bike over in a turn. The Fox swingarm for the 1979 was 2" longer.

Will the longer swingarm require a longer torque arm and brake rod or will the OEM parts work?

Is your swingarm designed with 17.5" or a different length shock?

mike

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9/21/2018 2:24 AM

Tokyo_Tiddler wrote:

Hi Stevie,

If I read your description correctly, the swingarm will have a weld line up the side like the old factory RC ...more

With the fox arm above and Stevie’s chain roller on the 79 above the stock length brake arm works.

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9/21/2018 11:37 AM

Tokyo_Tiddler wrote:

Hi Stevie,

If I read your description correctly, the swingarm will have a weld line up the side like the old factory RC ...more

Mike, yes the weld will be horizontal, the plan was to make them look like the "Coke Bottle" RC arms but with a little more modern twist.
The 2" increase makes a huge difference, they are much more stable and less twitchy but they still turn. (the main issue with them not wanting to turn is the fitment of 43mm forks and not sliding them through the yokes)

It's designed for the stock 17.5" shocks, and for the stock
chain guide to bolt straight on. A chain roller lowering kit would be part of the "kit". (Shock bolts, axle blocks, wheel spacers and brake rod)
With the lowering kit included, a stock brake trq arm could be used.
We might do a "factory" kit aswell, that would come with all the trick bits. Chain guide, brake arm, maybe an RC style rear spindle? Depends on the costs really. ?

I know how frustrating it is, having bought aftermarket stuff that then required a whole load of other parts and modifications that weren't mentioned!! And I'm lucky enough to have a 'shop where I can make pretty much whatever I need! So, for the average guy who doesn't have that access, it must be 10x's worse!!

So I want to supply them as a kit with all the head aches taken care of!
Buy it, un-box it, bolt it all on on Saturday afternoon with a beer and then go race on Sunday. No stress!!
It may cost a little more than buying just an 'arm, but I feel it's better way to do it.

Stevie

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Check out our website! www.phildentonengineering.com E-mail if you don't see what you're after!

The finest Titanium, Stainless Steel and Billet alloy components in the world!

Engine building, Race prep, Restoration

https://www.facebook.com/PhilDentonEngineering

9/21/2018 11:43 AM

Tokyo_Tiddler wrote:

Hi Stevie,

If I read your description correctly, the swingarm will have a weld line up the side like the old factory RC ...more

StevieD113 wrote:

Mike, yes the weld will be horizontal, the plan was to make them look like the "Coke Bottle" RC arms but with a little more ...more

Thanks Stevie,

Any estimate on the expected shipping date?

mike

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9/21/2018 12:31 PM

Don't forget me Stevie. You know, the guy with the 74 CR250M in desperate need of a quality swing arm....

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Photo

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9/21/2018 12:36 PM

I'm hoping to get started on the first prototype, (I might do 3... ?) In the next 2 weeks or so. Once I know it fits how it's susposed to, and get some hours of testing on it. We'll then get a proper run made up. Hopefully, ready in time for the new year.
I'd love to get them out sooner, but there's only one of me and I've got to keep all the other orders/work ticking over. Plus, it's taken bloody ages to get this far, it would be criminal to rush then now.
Stevie

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Check out our website! www.phildentonengineering.com E-mail if you don't see what you're after!

The finest Titanium, Stainless Steel and Billet alloy components in the world!

Engine building, Race prep, Restoration

https://www.facebook.com/PhilDentonEngineering

9/21/2018 12:46 PM

newmann wrote:

Don't forget me Stevie. You know, the guy with the 74 CR250M in desperate need of a quality swing arm....

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Photo

Once I get these out Newmann, Elsi arms are next.
After my experience with a '73a few weeks ago, I'm on the Elsi band wagon! (Honestly, the most fun I've had on a bike since I was 10!!) So I will be needing one for my own bike..... That I don't have yet..... I do have a Cylinder head, a rear brake pedal and a carb.... As far as I'm concerned, that's the start of a build.. ?

Stevie

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Check out our website! www.phildentonengineering.com E-mail if you don't see what you're after!

The finest Titanium, Stainless Steel and Billet alloy components in the world!

Engine building, Race prep, Restoration

https://www.facebook.com/PhilDentonEngineering

9/21/2018 1:52 PM

StevieD113 wrote:

Once I get these out Newmann, Elsi arms are next.
After my experience with a '73a few weeks ago, I'm on the Elsi band wagon! ...more

Head, brake pedal and carb? Yep, sounds like something we need to build a bike around! I've started with less...laughing

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9/21/2018 11:00 PM

I’m in for one.

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9/21/2018 11:09 PM

I’ll even volunteer to be an official test rider/part tester. Photo

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9/22/2018 11:22 AM

The quality of these will be spot on, Stevie did us a billet clutch basket for our RM125 , and it was spot on. Lovely attention to detail, and i am paid to pick fault with stuff.

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9/22/2018 10:44 PM

newmann wrote:

Don't forget me Stevie. You know, the guy with the 74 CR250M in desperate need of a quality swing arm....

Photo



Photo

StevieD113 wrote:

Once I get these out Newmann, Elsi arms are next.
After my experience with a '73a few weeks ago, I'm on the Elsi band wagon! ...more

The CR Elsinores are a lot of fun in the corners.. you focus more on corner speed than things like jumps and woops so it is a different experience.

Sounds like it may be another 4-5 months before you are actually shipping. mandatory testing will be putting the bike up on the garage roof with a forklift and jumping off for a few flat landings to test the strength smile

Will you be sending the arms out to another shop for welding and heat treatment? Clear anodizing them would also be a plus.

mike

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9/23/2018 12:18 PM

Stevie, you can count me in for one.

Mike, I am going to powder coat it red

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9/23/2018 12:54 PM

PK97 wrote:

Stevie, you can count me in for one.

Mike, I am going to powder coat it red

I will probably do the same.. Red Rockets don't look right with silver swing arms.

mike

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9/24/2018 9:05 PM

VintageRacer wrote:

Stock chain roller or will we need to buy yours? Photo

Vintage Racer: Where did you get that bike stand? I have ben looking for that type similar to one I brought back from Japan but could never find one.

mike

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9/24/2018 9:06 PM

Stevie;

Please send post pics of the prototype as soon as you can even if a work in progress!

mike

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9/26/2018 11:25 AM

VintageRacer wrote:

Stock chain roller or will we need to buy yours? Photo

Tokyo_Tiddler wrote:

Vintage Racer: Where did you get that bike stand? I have ben looking for that type similar to one I brought back from Japan ...more

A shop here in Michigan sells them. I’d have to ask a friend where he got them from, I’m not sure.

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9/26/2018 1:02 PM

PK97 wrote:

Stevie, you can count me in for one.

Mike, I am going to powder coat it red

Tokyo_Tiddler wrote:

I will probably do the same.. Red Rockets don't look right with silver swing arms.

mike

I may have to argue that one.smile

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