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Tll130
| | Posted on Tuesday, September 24, 2013 - 11:51 pm: | 
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I agree with you it makes perfect sense to me besides there are a ton of 1125 engines around |
Greg_cifu
| | Posted on Wednesday, September 25, 2013 - 01:31 am: |
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OK, well, Engineering student or not, why not build a proper lattice frame for it?
A Buell tuber frame is designed to create a structural cage to carry the loads AROUND an engine and allow it to shake up and down inside.
The Rotax engine is designed to be rigid mounted and be a semi-stressed member. It's designed to have the frame firmly attached and the loads passed directly into it.
Their design objectives are completely opposite from one another and neither supports the other very well.
Why not make your own lattice frame, picking up the engine mounting points and providing a subframe to hold the rider up off the rear tire (the only real purpose of a subframe)? It would be neater, more compact, lighter and probably less work than trying to figure out how to attach a tuber frame to a Rotax engine. Use just about any tube-framed Ducati as inspiration.
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Easy_rider
| | Posted on Wednesday, September 25, 2013 - 07:19 am: |
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WTF is wrong with the stock frame
The tank in the frame sounds like a cool idea, but in reality it's a large heat sink. I love the power of the 1125, but for real world riding I like not being toasted by my tuber.
The "build a proper frame" idea is pretty cool though! |
Hughlysses
| | Posted on Wednesday, September 25, 2013 - 07:56 am: |
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I will not be doing this build. I am putting an 1125 engine into a Harley FXR, vrod radiator up front. I'll post pics some day.
It sounds like an interesting project. You should start an entire webpage of photos of the looks you get from the leather vest crowd when you tell them what the engine is.  |
Reepicheep
| | Posted on Wednesday, September 25, 2013 - 08:51 am: |
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Geesh. Can you really get an 1125 motor for $800? |
Lynrd
| | Posted on Wednesday, September 25, 2013 - 09:55 am: |
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So, he said this was a food for thought exercise - this engine is going into an FXR. But I disagree about the "Design goals" statement - the stock engine in a tube frame bike is also "designed to be rigid mounted and be a semi-stressed member. It's designed to have the frame firmly attached and the loads passed directly into it. " It's a Sportster, remember? And that was how Sportsters were built for 40 years.
Building an entire frame, particularly a trellis frame, is not going to yield easier or better results than reusing a tuber chassis. and to build one correctly there are some complex and capital intensive tooling costs involved. If you try to do it without a proper jig, you may create a beautiful sculpture but it is doubtful it will be something well suited to carry that 175 hp engine under its own power.
There would be more than a few major obstacles to overcome. but no more than there will with the FXR project. Of the two, i like this one more. THe FXR (and the FLT) are the best frame HD has ever had, but it is still a heavy mild steel thing.
That said, I personally wouldn't bother, as the electronics and fuel injection of the more modern Buells just leave me cold as a customizer. But I would love to see either idea completed and have the opportunity to check it out. |
Greg_cifu
| | Posted on Wednesday, September 25, 2013 - 10:37 am: |
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I think you and I have been working on entirely different tubers. The four I have sitting here have the engine attached to the frame at three rubber mounts. Remove those and the only thing keeping the engine from falling out of the frame is 3 (or 4) heim joints.
By-design, they attempt to allow the engine to flop freely in the vertical plane. How is that rigid mounted like a Sportster? The sporty--until the end of 2003--was bolted solidly into the chassis. It moved nowhere. |
Lynrd
| | Posted on Wednesday, September 25, 2013 - 11:27 am: |
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No, I get what you're saying and my tubers all seem to be the same kind of tuber as yours. And for you, me, and every other tuber owner, the original power plant was a engine that was designed for the rigid mount, stressed engine Sportster frame.
The thing is - you pointed out that the engine was designed to be a stressed member on the 1125. And I have to point out, that the engine is also intended to be a stressed member in the original sportster that it was lifted from. Erik's design took that solid mount motor and moved it to the uni-planar isolation design. I don't see what precludes the same thing from being done with an 1125, or a Honda 750, or a Briggs and Straton.
The Uni-planar design in the tuber is sound, I am sure you would agree. Retaining it and making it work with a different motor is going to take some fab work, but if you pull it off, you are answering exactly the same problem statements that were answered when Erik and crew crammed that first XR-1000 into the first RR-1000.
/later -re-reads thread - Oh, originally the discussion was around solid mounting in the tuber frame. Ok, well, that's just silly. Now I like Rex's idea of putting it in a featherbed and making a BueTon.
(Message edited by Lynrd on September 25, 2013) |
Lynrd
| | Posted on Wednesday, September 25, 2013 - 11:33 am: |
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BTW, Greg - bonus points for the pic of Wild Bill Gelbke! When I see one of those stupid Chevy v-8 bikes or trikes, I always call them Gelbke's...I have yet had an owner figure out what the hell I am talking about... |
1313
| | Posted on Wednesday, September 25, 2013 - 12:26 pm: |
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I sent a buddy of mine a link the first day this thread appeared. His response:
"That is a very cool idea. It would be a packaging nightmare but nothing ventured nothing gained. I would put the air box on top, fuel in the swing arm with an external pump, a curved Ducati radiator behind the front wheel and the rear shock next to the engine, opposite the header like a Bimota. Problems solved!"
FWIW,
1313 |
Hybridmomentspass
| | Posted on Wednesday, September 25, 2013 - 12:39 pm: |
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Oh I cant wait to see this FXR! I love those bikes, and with this motor it'll be really neat.
Where are you getting 1125 rotax motors for under a grand? |
Tll130
| | Posted on Wednesday, September 25, 2013 - 01:00 pm: |
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eBay last I checked I seen all the buy it now prices around 800$ |
Deanh8
| | Posted on Wednesday, September 25, 2013 - 01:46 pm: |
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Yup eBay. Honestly you don't expect me to rubber mount the engine. Biggest problem with making the FXR handle well is trying to find good rubber engine mounts and primary clearance. Solid mounting the 1125r engine to the FXR frame eliminated all the rubber isolators and allows the chassis to be stable. Also no primary allows for more ground clearance, no oil bag allows for a mono shock under seat, no rear trans allows for the swing arm to be solid mounted to the frame. You just run a whole wiring harness off the 1125 with the 1125 ecu and everything. Very straight forward. You need custom manifolds to put the throttle bodies on the side though. That's easy though
I bought two 1125 motors on eBay for less then 900 |
Lynrd
| | Posted on Wednesday, September 25, 2013 - 06:32 pm: |
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Yeah, makes sense. I would question using a tuber frame that way because that thin wall chromemoly can be pretty sensitive to vibration, but with an FXR frame, I don't think it would be a problem.
If you are going to attempt this with a tuber frame, I think you'd have to solve for rubbermounting and getting the suspension geometery correct enough that it rear isolators hold still.
The FXR sounds like a damned slick project. |
2kx1
| | Posted on Wednesday, September 25, 2013 - 06:36 pm: |
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Dean
www.taimoshancycleworks.com |
Jim2
| | Posted on Wednesday, September 25, 2013 - 07:05 pm: |
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Can the 1125 motor be solid mounted to the tuber frame? If so then just replicate the rubber isolators with steel and mount. An adapter could be made in the front that bolts to the existing front iso mount like an upside-down U or Y. Bolt that to the engine (I don't even know what the 1125 engine looks like for mounting) and then bolt the radiator pods on the outside of the U or Y bracket below the existing tuber airbox.
The pods would scream, "I'm a water cooled tuber". |
Greg_cifu
| | Posted on Thursday, September 26, 2013 - 12:03 am: |
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quote:Oh, originally the discussion was around solid mounting in the tuber frame. Ok, well, that's just silly.
OK, NOW we're on the same page. I was talking about the Sportster vs Tuber FRAME, not the engine. I can see why my posts seemed confusing. |
Akbuell
| | Posted on Thursday, September 26, 2013 - 08:19 am: |
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Since this is a subject for conversation, one question comes to mind: Would a tube frame be able to handle 70 more horsepower?
Cool idea, fun to think about, but the result might be a 'flexi-flyer'.
The FXR sounds much more practical. And the Bill Gelbke story, and the background, is interesting. Lots of questions there.
Dave |
Trojan
| | Posted on Thursday, September 26, 2013 - 09:30 am: |
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And I have to point out, that the engine is also intended to be a stressed member in the original sportster that it was lifted from
The original Sportster motor may have been solid mounted, but it was never a stressed member or designed to be an intregral part of the chassis. It was basically just a very simple engine solid mounted into a very simple cradle frame.
The original Tube framers were built to take 100bhp max really, and the rear suspension was always the weak point because the design is flawed. Putting a 125bhp water cooled motor in with the extra weight and power would probably tie it in knots.
Have a look at decent aftermarket frames from Harris, Spondon or Bakker to see how the experts do it  Building a complete frame from scratch may actually be simpleer and more effective in the long run than trying to make the 1125 motor fit the tuber frame.
As for putting an 1125 motor in an FXR frame....Don't you have any corners where you live? |
Lynrd
| | Posted on Thursday, September 26, 2013 - 09:37 am: |
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Well, you can get stiffness out of material, or out of geometry. Using the FXR, you're doing some of both. With the tuber frame, you are relying almost exclusively on geometry.
I think that any of the later tube frames with the added brace for the front stay would stand up to it, and I think the S2 would as well since the front stay is a pure triangle.
As for the 96-98 frames without the additional brace for the reaction link stay, well, I think the bent front reaction link stay is a design flaw. That is from a basic frame theory standpoint, I have no evidence that it is (other than the factory choosing to correct it after a few years). If using one of those frames, I would address the bent front stay.
There is another word for a bent piece of steel - we call that a "Spring". Straight tubes, even small diameter tubes, and correct triangulation will yield a lot of geometric stiffness with little weight....But as soon as a designer chooses to or must deviate from those principles into bent tubes, parrallelograms and trapezoid shapes, he must rely on the material itself to provide what stiffness it can.
Now, if you want to discuss feeding high frequency vibrations into a welded chromemoly frame and how long it would take the tubing to fail due to work hardening, that is another subject... |
Deanh8
| | Posted on Thursday, September 26, 2013 - 01:04 pm: |
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@ Trojan
Yes lots of twisties, My FXR has BPF Showas, Brembos all around, deraked 3*, if this motor works out its going monoshock
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No_rice
| | Posted on Thursday, September 26, 2013 - 01:39 pm: |
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Have u guys seen the Suzuki watercooled TL powerd XB?
no, where? i would like to. |
Deanh8
| | Posted on Thursday, September 26, 2013 - 01:56 pm: |
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One could argue an 1125 engine is simpler, makes more power, is lighter, etc but I think its badass just because its different
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No_rice
| | Posted on Thursday, September 26, 2013 - 02:03 pm: |
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where the hell is that from?! amazed ive never seen it before now |
Hughlysses
| | Posted on Thursday, September 26, 2013 - 07:35 pm: |
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Since this is a subject for conversation, one question comes to mind: Would a tube frame be able to handle 70 more horsepower?
Cool idea, fun to think about, but the result might be a 'flexi-flyer'.
It's not horsepower that bends the frame, it's torque. I'm pretty sure the HD twin has more peak torque than the 1125 engine.
Now, ~70 more horsepower may well cause other issues, including showing up the limitations of the suspension, brakes, etc., but I still think it'd be a really cool project. |
Gbackus
| | Posted on Thursday, September 26, 2013 - 09:19 pm: |
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do want |
Tll130
| | Posted on Thursday, September 26, 2013 - 09:52 pm: |
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I understand the stress but what if one was to do a Xb swap with the under the seat shock and then swap the 1125 engine in it? It should handle more that's what I'm thinking all this gossip about it is making me think of putting one in mine. Anyone want to trade a full setup for a full setup sportster engine gearbox and engine n wiring harness. From a 00 x1 |
46champ
| | Posted on Saturday, September 28, 2013 - 10:28 am: |
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Dean I need detailed drawings of the adapters you need to build to get an 1125 motor into a tube frame. I have almost decided to quit drag racing the Sportster and go to an 1125. The drag racing world needs an 1125 bar bike and I think the quickest way to go is to graft on a solid rear end to a X1 frame, and probably rake the front end which would be way easier with a tube frame rather than the stock 1125 frame. The other reason I want to use a tube frame is to get the frame around the induction system. |
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