Scorpio - why my Cafe Racer's not finished

beachcomber

TJ - Beachcomber
DTT SUPPORTER
Not sure how Trikes might be viewed here ..............but it can always be removed if it offends !

Here's the reason that my TR1 Cafe Racer and BMW Fighter remain unfinished !

2 years ago it became obvious to me that an old Football Knee injury [ curse of Centres - centers ] would put paid to my solo riding sometime in the next 5-10 years. So, I decided to embark on a Trike project to keep the juices flowing. After a couple of false starts [ Trad layout and BMW Kay powered reverse Trike ], we settled on the BMW Oilhead powerplant. I started to develop this with my old pal over at Realm and after another couple of blind alleys with Honda and Suzuki donors - it became obvious we need a very low COG and forward control riding style. The Boxer was ideal for this concept and we soon got into the driving prototype stage. My pal was getting a bit jaded with the day to day production of Cobras, D Types and C Types [ !! ] and wanted a bit more of a challenge.

So what started as a bit of a selfish whim, became an all out engineering and styling challenge. We set ourselves an unveiling date at the October Classic Bike show in Stafford [ UK ]. Well - we might just make it - sadly the TR1 [ "Vindicator" ] Cafe Racer will have to wait until the April show next year.

So here's the reason my personal projects are not finished ! Seen here in rough patternmaking form for the body panels [ now moulded ]. We've gone for some modern thinking for the suspension - inboard push-rod coil overs at the front and a truly unique rocking pivot rear. we even had to manufacture our own driveshaft and housing. basically only the BMW powerplant and electronics are retained.

 

beachcomber

TJ - Beachcomber
DTT SUPPORTER
The body panels have just been surfaced and given a finish spray coat. We'll then take a set of production moulds from those finished items.

Just a few finishing touches on the rolling chassis and wiring and I'll have some decent pix to post up.

The Trike is due to be displayed at the upcoming show 1th / 16th. October - yea, this October !!! So I hope you'll forgive the lack of decent photos for the next few weeks.

The attached pic is of the first set of rough panels - they've been surfaced and painted over this weekend - finished moulds this week.
Actually, the powerplants in the pic are #'s 2 and 3 - #1 is still a rolling test bed.

 

beachcomber

TJ - Beachcomber
DTT SUPPORTER
gentlemanjim said:
Is the grey frame with the big radiator your Trike project?? Or did you post the wrong pic?

Ahhhhh - no that just happened to be in the workshop at the same time. It's the chassis for the next C Type Jag replica due to go out to Australia in the next month. Yet ANOTHER reason why the bike projects are held up ! The 2 BMW powerplants are in the background. I'll post chassis pix later - you can see the front clip on the bike with the prototype body panels.

In true Blue Peter style - "here's one we made earlier"

 

beachcomber

TJ - Beachcomber
DTT SUPPORTER
BIG E said:
Keep us informed I like it even if it is not exactly a cafe. :)

BigE - like I said, I'm quite happy to remove the thread if it causes offence.

The Trike has been concieved in the "Hooligan" style and HAS sprung from the brains of early Cafe Racers !
 

beachcomber

TJ - Beachcomber
DTT SUPPORTER
For the technically inclined, here's the rear monoshock suspension -

In gobledegook speak it's a "horizontally sprung and dampened latterally displaced rocker operated suspension"..............OK I made that up.

Th unit shown is the working pre-production unit - production unit has been made aesthetically more pleasing!

Works amazingly well, even if I do say it myself!

Only 10 days to the show ..OMG

 

beachcomber

TJ - Beachcomber
DTT SUPPORTER
Specially for Erskine .......

Originally I was going to hide the operating link, and then just stand back and watch people scratch their heads !!!

OK - in the foreground is a short vertical link with Heim joints each end. The bottom is attached to the diagonal brace that comes off the new drive shaft housing.

That is then connected at the upper end to the rocker arm which is then pivoted and dives vertically downwards to pick up the shocker. The other end of the shocker is attached to the Driveshaft tube.

The production item has been made more "cosmetic".

The beauty of this system is that you can use a much softer rate spring than with a normal vertically mounted monoshock.
Typically you would need about 900lbs for that, whilst this system uses 400lbs. So you end up with a much more compliant ride, but still controls everything properly with a full operating supension range.

Wait 'til I show the inboard pushrod operated dual coil overs on the front end ! :D

Now can you see why the TR1 and BMW Fighter have taken a back seat for the past 4 months ::)
 

beachcomber

TJ - Beachcomber
DTT SUPPORTER
Front end pix in 10 days time - sorry for the delay, but the front end of the Trike is all clagged up with modelling clay and cloths while we fine tune the bodywork.

We deliberately modelled in a '27T [ !!! ] style nose so that the diagonally rearward facing coil overs are on display as a bit of an engineering feature.

I hope to get some decent pix at the show - if ever we get there ! If so I'll shoot 'em up on the forum when we get back.

 

Curtis

Active Member
I have always been intrigued by a reverse trike, and have often thought about building my own.

Did you make the frame yourself, or is it a hacked up quad ?

Thanks,
 

beachcomber

TJ - Beachcomber
DTT SUPPORTER
Hi Curtis,

It is a clean sheet of paper design with all parts made in house.

Realm actually manufacture the C Types, D Types etc. you have seen on my posts - including jig welded chassis', transmission adaptors, etc.,etc.

After designing and building 25 of the award winning RAM Cobra race cars a Trike is not too difficult !

If you do go for it - DON'T start off with a quad, you will give yourself no end of headaches. Afraid it's not as simple as getting a 4 wheeler and throwing 1 wheel away.

Attached pic is Pete Brock and Bob Bondurant with several of our RAM / Bardahl Trophy race cars in the background at Le Mans where Shelby drove one of our cars on the parade laps. I drove another RAM race car with the French TV cameraman to capture the event.

 

gentlemanjim

Been Around the Block
I like the concept. To keep it simple and relativley inexpensive what are your thoughts on grafting a quad 4 wheeler front end to a bike of choice?
 

beachcomber

TJ - Beachcomber
DTT SUPPORTER
Sorry Jim - simply won't work.

The suspension geometry requirements for a Quad are completely different to that of a reverse Trike. The Swiss Taurus trike was spawned from one of their successful Quad designs. A beautiful piece of engineering - but even they had to add 50 kgms of weight on the front to get it to work - 'ish.

We [ Realm ] THINK we know what we're doing after 45+ years of auto engineering design, but believe me a Trike is a whole new learning game.

IF you go for the traditional Morgan set up with side by side seating it's relatively straightforward - the problem arises when you want to use a motorcycle sit on rather than sit in seating arrangement.

Now it IS perfectly possible to get the sit on style to work - we have, but it requires a whole different approach to the suspension dynamics.

Here's some tips - get the COG as low as possible - then lower. Get as much weight forward as possible.

Several [ very clever ] manufacturers have discovered this problem along the way.

Basically a bike back end with two wheels at the front will not work - trust me, we tried ! The results are frightening.

The resultant contraption doesn't handle like a car, bike or sidecar and doesn't respond to "normal" fixes.

We successfully designed, built and raced a one make series race Cobra - so we thought it would be simple when it came to building a trike - wrong ! ;)
 

Basement rat

Over 1,000 Posts
We have these around here...



We consider them very... Camp I think is the word. However yours is the way it should be! I would ride yours (with your permission). Its just right!
 

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