Topic: CB650 Gooseneck trike

[Sprocketwerx]

Started this years ago, not as a trike, just a chopper build that ended up on the back burner for one reason or another.
"81 CB650 Custom, sad shape but complete enough for my purpose.

Here's the stock frame on the jig.


Here's what got cut off.


Here's what I replaced it with.

[Sprocketwerx]

It got set aside and when I decided to build a trike for my wife, I originally planned on a CB400A in the shed.
Then I thought about it and decided, "she needs to learn to shift sometime!" and the CB650 goosey came back into the picture. Frame's done, motor runs (need to sort carbs) I have a springer...
An old work bud gave me a '67 MGB spline drive axle (he has the front disc brake stuff I need too  )
Picked up a set of spline drive wheels in fair condition.

The original plan was to align the ring gear as if it was the sprocket that will replace it, and shorten he left side axle 4.5" to balance out the centerline.
I've since decided to save me some work, create a little more work, and have a more stable trike.
I'll use a jackshaft to align the front drive with the natural position of the ring gear in the differential. Chain drive right up the middle.

Suspension will be ladder bars with diagonal link (maybe a wishbone) and anti roll bar, 70s drag car style 

Here's a few mockup pics.

[Sprocketwerx]

I don't know what I'm doing wrong, insert image, paste photobucket linc between the brackets, and no pic...

[chewbacca5000]

Bump.  Someone please give this guy some help I want to see pics of this build.

[Sprocketwerx]

I'm a dummy...lol
Was using the URL instead of URI.

DUUUUUUHHHHH! :S

[chewbacca5000]

Nice work really like it so far.  Don't understand why you want the swing are to be so much longer.  Just can't see the benefit there.  Also not sure if you are going to have enough displacement to move all that steel.  Other than that it look great.

[Sprocketwerx]

I'm thinking it's too long in the back too. Just working with what's on hand. The ladder bars were a freebie after I set up a 4 link for a racer friend.
They can be shortened and most likely will be.
Just need to find that happy medium
There will be a "trunk" for storage under and behind the seat, so there needs to be enough space.

Not looking for a hotrod, it's my wife's first bike, she's never driven anything less than 4 wheels, so I'm not worried about enough power.
Rear wheels will be stock MGB so no steamrollers to eat up HP.

[chewbacca5000]

I'm thinking it's too long in the back too. Just working with what's on hand. The ladder bars were a freebie after I set up a 4 link for a racer friend.
They can be shortened and most likely will be.
Just need to find that happy medium
There will be a "trunk" for storage under and behind the seat, so there needs to be enough space.

Not looking for a hotrod, it's my wife's first bike, she's never driven anything less than 4 wheels, so I'm not worried about enough power.
Rear wheels will be stock MGB so no steamrollers to eat up HP.

So the big fat wheels are what use up the HP?  I did not know that interesting.  Having a trunk is a nice addition gives it some utility to go get groceries and such.  Keep up the good work I will be watching this thread.

[Sprocketwerx]

More weight to turn, more friction via contact patch...
Much like high octane fuel, if your motor isn't pinging, you don't need it.
Same with fat tires, if your motor can't turn them over, they only LOOK fast.

[Garystratos201]

Interesting and complicated build. I`m in.............Gary

[Sprocketwerx]

Bending up the rear frame today, should have pics of it tacked in place this evening or tomorrow.

Ladder bars will be severely shortened from both ends. Not worried about strength with these, they launched a 3400# Chevelle for years
I need to find an 8 point bearing wrench for the MGB outer axle bearings, and source sealed bearings for both the outers and the inner diff carrier. The spider gears will be fine packed with high pressure grease, and the spinning diff will be visible. I might even do something silly after it's running, and get the diff chromed and stick some LEDS in there


I'm thinking of just mocking up a plug for the trunk body and lay it up in 'glass (I need to repair my boat transom anyway, 2 birds and all that). All hardware will be laminated as well as strengthening/attatchment devices, including a steel chain tunnel.

[Sprocketwerx]

Top view of the rear frame just sitting up on blocks. Need to cope the ends before welding. The ladder bars will swing just outside of this bar


Side view of the same, there will be a tube brace from where I cut the frame directly behind the swingarm pivot to about 2/3 of the length of straight.
Material is 1.25ODx.120wall DOM, as is the backbone/"seatpost" and crossbar that supports it.


Here it is with the seat and tank in approximate position


And full side view with frontend length (it will have a springer and spokes but for porportion, these tubes are close)

[rb550four]

I kinda like the elongated rear wheel location , I would expect the front wheel to bite a bit better and it should take a bit more energy to flip it over sideways.
 What kind of suspension do you have in mind?Mg springs? 650 shocks? It's a strange (to me) and interesting project.
 

[Sprocketwerx]

I was going to use the stock shocks, but I have some nice pieces from an XS650 tracker. The Yammy shocks are eye to eye, so easier to mount on the axle end.
They will be staggered and ride outside of the frame. There will also be a sway bar to control roll on corners.
I was debating between a diagonal link or a wishbone to keep everything straight and square. I think I'm gonna do a wishbone, 2 legs to the frame and a single on top of the diff housing. It will be a slip joint so it can compress and retract through the suspension cycle.


Welded up the rear subframe today and shortened the ladder bars by about 3", need to tap for the hiem joint, and source 2 soloid rod ends with left hand threads.