Ace UCE project.

[nigelogston@gmail.com]

The Carberrys use the standard Bullet frame ...

http://www.carberryenfield.com.au/OLDBIKE.pdf

Actually,Glenn, if you look at the picture of the Carberry you posted, it ihas a partial dual downtube frame more or less like I was suggesting bolted to the front of the engine casing and goint up to headstock..   I hadn't noticed this before, though I have seen pics of the Carberry, because, I guess I wasn't thinking about the frame but focussed on the pretty  v twin.   So I think they may have anticipated a similar problem.  Plus, they may have needed the space in front (where the front cylinder head has to go) an had to cut out the single (and much heftier I might add) downtube of the stock bullet replacing it with the spindly black bits that look like barbecue legs.  No points for the asthetics of their partial double cradle though.   
With the beefed up single UCE space and clearance would not be issues, but surely frame stability could be increased by something like an alumiinum plate cut out of course for air flow in a graceful A form going from roughly the same point on the bottom of the engine casing as pictured on the Carberry up to the headstock, attached there , perphaps by a  spit circumferential clamp and bolt arrangement to the uppermost part (or highest accesable part) of the fat single downtube.  Could even double as a skid plate by sweeping under the engine and attaching to its sides somewhere below like a bash plate.  Not having one to look at, I can't quite see where the attachment points would best be, but the general idea would be to create a triangle in the cross sectional plane to give torsional stability and avoid the :"noodle" effect Scott referred to.  Might be just as important in terms of the goal of "tractability" as good engine mods.  Just saying is all.  Nigel 

[Arizoni]

Mine handles very nicely for a 1955 designed frame.

MUCH better than my old Honda CX500 did.  

[nigelogston@gmail.com]

Thats very interesting Arizona .   I never looked at those (Honda CX ) before, but it looks like a single downtube frame as well with the engine bolted on as a stressed member-ie same as Bullet.  I wonder why the big difference-----shaft effects maybe?

Boy have I got thebike  bug bad.  And I still seem to be suffering the with RE strain of it.   Hope spring breaks through soon so I can ride it out.   Nigel

[ace.cafe]

Ace, love the v twin!  Though I'm partial to the look of a parallel I really respect the idea of just building the bottom end and using existing stock parts for the top.  Will this fit in a standard UCE frame?

I hope the factory cafe gets a parallel twin at some point.

The single down tube, engine as stressed member frame with all the disparate parts bolted together is a noodle.  How could it not flex, even under just stock power?   That said, you can probably put lots of power through it without breaking it, it just may not handle as well as you'd like.

Scott

Scott,
It was designed to fit in the Iron Barrel frame, with a modified(stretched) top tube under the tank.
The UCE frame might complicate things further,because the V-Twin is designed to operate with the pre-unit gearbox, and its primary chaincase
It might go in there, but I don't know what it would take to do it.

[ace.cafe]

Regarding the single-downtube open-cradle frame design, it's actually pretty good.
There are a lot of good handling bikes which use that.

Here's one. Ducati 450 Desmo Sport.
Notice a similarity?
I heard these bikes handled pretty good!



I wouldn't be worrying about it.
I can tell you from experience that it handles rock solid to well over 100mph, and will run right alongside a Manx with a featherbed frame. At least, the Iron Barrel models will. Like a Fireball.

BTW, an Ace Fireball 535 will whip that Ducati 450 Desmo all day long.
Who says Bullets are slow?

[Ducati Scotty]

I stand humbly corrected.  Noodle comment retracted   Ducati is still using the engine as a stressed member of the frame.

Scott

[nigelogston@gmail.com]

OK   : frames good to 100..  Interestingly that Honda CX 500 mentioned    gained noteriety by geting on a list of "10 worst handling motorcycles"  and top heaviness and shaft torque effects were cited .  There is also a "10 best handling " list which includes at least one single down tube bike, the Honda 750 4 :  i think all the Brit entires (several ) are dual tube though is fared and I can't tell.
By the way anyone seen the announcement of the new" C5 special" with different front forks and 19 inch wheel for "more cruiser like handling "  (5 days ago)  .
Nigel

[Ducati Scotty]

Where was that to be released?  India, Europe, US, or all?

I'd be ineterested in just getting the fork lowers if they can be mounted to the existing bike.  My bike it fine all the way up to terminal velocity but RE parts are usually inexpensive and I'd like to compare/contrast.  It would only take a few hours to swap them over.

Scott

[barenekd]

There is a post about it at the top of this forum under "Announcements"
Bare

[ace.cafe]

It should give more trail with those fork sliders, and also more gyroscopic stability with the bigger 19" front wheel. And the 19" front wheel will probably be a little taller in the front end too, which will increase the trail even further.
I think this is basically an admission of a frame geometry problem, and this is the band-aid.

[ace.cafe]

It should give more trail with those fork sliders, and also more gyroscopic stability with the bigger 19" front wheel. And the 19" front wheel will probably be a little taller in the front end too, which will increase the trail even further.
I think this is basically an admission of a frame geometry problem, and this is the band-aid.

BTW, my old Ducati 750 bevel twins had a 19" front wheel and and 18" rear wheel, and those bikes were famous for great handling and stability.

[barenekd]

The larger front wheel  will also add a bit to the trail. The article I saw in the Factory website also mentioned moving the fork legs back closer to the steering head for even more trail.
Should have enough with all that!
Bare

[nigelogston@gmail.com]

I am curious then as to which would be better for stability and handling;  The C 5 special with the 18 inch rear and 19 inch front and "new"  forks, or the G 5  with both front and rear 19 inch and its "old" forks and greater rake.  Or the B5 (based on 350 frame) which I suspect  (but don't know) has less trail and rake than the G5, but also, I believe has 19 front and rear.  Thoughts?  I have always been drawn to the look of the G5, and my guess is that low speed manouverability aside, it is the best road speed set up.   Front wheel on C 5 always did look too small to me from an asthetic standpoint. . 
In other words is it the 19 inch front that confers stability, or the slope between the 19 inch front and 18 inch back combined with rake and trail changes thus established.     (Getting a bit off topic of the original thread here, but hey, it is a G5 that is the test bike coming in anyway ) Nigel

[1 Thump]

Yep its a G5 from what I hear, but its going to end up as an F5 

[Ducati Scotty]

Nigel,

Trail is usually the most important factor.  Whichever has the most trail is probably the most stable.

Scott