Oddball engines and prototypes

[J.A.W.]

most likely
whats the benefit of having split crank bearings vs 'normal' ones

Huh?

Do you mean plain bearings - one piece crank?

Original Norton Commandos had a "split" crank with plain big end bearings & rolling element mains..

[husaberg]

most likely
whats the benefit of having split crank bearings vs 'normal' ones

and
have you considered the Super Tenere offset 270' crank does that fit in with the current discussion?

its interesting that BMW use a Rotax designed twin as they also make racing and aero engines and maybe outboards as they are part of Bombadier group - they would have a range of design knowledge at hand

engine noob

Are you meaning plain?
less friction, cheaper to make and service (Multis)more rigid, but needs high pressure and clean oil

Roller bearing
Making truing assembling and disassembling a multi cylinder pressed up crank is expensive and fiddly.

That single BMW (Supermono) had a rotax as well they likely can't be arsed, when there is one they can use of the shelf. BMW was tied up with Husky last I heard.
the tenre or TRX is a 90 crank 360-90 =270. they called it that to distance it from A Ducati.

[J.A.W.]

Helmut did not do just the one.
After he had become sidecar world champion with a BMW, he had some difficulties in making BMW listen to his wishes, so he built the 500-4 URS engine, a four-stroke with a number of novel ideas like the 90°-cranks, the split inlet tracts and the Kugelfischer fuel injection.
Later in life he saw the light and built a 500-4 two-stroke boxer with four rotary inlet discs; two contra-rotating discs stacked above one another for each pair of cylinders, so the inlet ports would open twice as fast. And finally he built a 250-2 boxer, the HF3.
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Thanks F, that flat-4 is a bit Konig-like..

[husaberg]

Thanks F, that flat-4 is a bit Konig-like..

MV did a boxer as well.

[J.A.W.]

Are you meaning plain? less friction, cheaper to make and service (Multis)more rigid, but needs high pressure and clean oil

Making truing assembling and disassembling a multi cylinder pressed up crank is expensive and fiddly.
That single BMW had a rotax likely can't be arsed, when there is one they can use of the shelf. BMW was tied up with Husky last I heard.
the tenre or TRX is a 90 crank 360-90 =270. they called it that to distance it from A Ducati.

No, plain has more friction, but needs more oil flow too, which can be used as an internal coolant..

2Ts have managed pretty high specific outputs with their rolling element cranks, & big Z1 & GSX 4s have stood plenty of boost - as drag bike mills too..
BMW sold Husky to KTM, & their 2T DFI tech with it..

[husaberg]

No, BMW sold Husky to KTM, & their 2T DFI tech with it..

That explains why they are not so ugly now maybe.
the irony is Husaberg started because the engineers wanted to stay in Sweden when Cagiva brought them
Then KTM brought Husaberg and now they buy husky and they are all back together then.

[eldog]

Are you meaning plain? less friction, cheaper to make and service (Multis)more rigid, but needs high pressure and clean oil

Making truing assembling and disassembling a multi cylinder pressed up crank is expensive and fiddly.
That single BMW had a rotax likely can't be arsed, when there is one they can use of the shelf. BMW was tied up with Husky last I heard.
the tenre or TRX is a 90 crank 360-90 =270. they called it that to distance it from A Ducati.

meant split crank bearings, sorry Husa I dont understand your answer.

BMW was thinking F800 GS parallel twin, sounds quite different.

I am going to have to look more into this so I can start to follow this thread.

[husaberg]

meant split crank bearings, sorry Husa I dont understand your answer.

BMW was thinking F800 GS parallel twin, sounds quite different.

I am going to have to look more into this so I can start to follow this thread.

Split bearing are plain bearing.
I listed the pro and cons of each.
Your bike will have plain bearings
To make it sound different would not be worth it buy a Ducati or TDM or other offbeat firing twin.
It would need the balancer sorted the cams changed and made not to mention a new crank or bloody extensive modifications
Your one has the oddball pivoting balancer stirrup balancer though I think.
Get an ipod and play the sound of a vtwin.

[husaberg]

No, plain has more friction, but needs more oil flow too, which can be used as an internal coolant..

2Ts have managed pretty high specific outputs with their rolling element cranks, & big Z1 & GSX 4s have stood plenty of boost - as drag bike mills too..
BMW sold Husky to KTM, & their 2T DFI tech with it..

No way the plain bearing has almost unlimited rev Capability roller can only go so fast before they start skidding. if it was a 8000rpm plodder maybe less friction
They were great for what they were but too expensive these days for mass production or servicing long term.

Those early Hondas had built up cranks and very very special rollers but I don't think they could have made and ground a crank that small as the 125/5

[J.A.W.]

No way the plain bearing has almost unlimited rev Capability roller can only go so fast before they start skidding. if it was a 8000rpm plodder maybe les friction
They were great for what they were but too expensive these days for mass production or servicing long term.

How fast? What bearings does the Ryger use?

Yeah, plain bearing cranks are cheaper for mass production, but shit themselves at the 1st hint of oil starvation - in perfomance applications..
& recips are generally limited by piston speed before rpm, anyhow..

[Frits Overmars]

Split bearing are plain bearing.

Seattle Smitty is going to tell you that most outboard engines have split roller bearings on their crankshafts.
And I once had the pleasure of dismantling an MV Agusta 750S that had them as well. Most overrated and overpriced bike I ever tested.

[ken seeber]

Jeez, hadn't looked at this site for a couple of days. Whammo, pages and pages of memories, frames and engines.
Don't chew guys have jobs? You know, pay taxes so your govt's can spend on things you don't want them to.
Anyways, I thought I'd have an indulgence by throwing in some snaps, some from my old scrapbook. I just loved the GP tiddlies. I just loved the picture of the Ossa. Santiago H must have been tiny. One of Jan Thiel, a guy who in many ways brought us all here.

[husaberg]

Seattle Smitty is going to tell you that most outboard engines have split roller bearings on their crankshafts.
And I once had the pleasure of dismantling an MV Agusta 750S that had them as well. Most overrated and overpriced bike I ever tested.

Only because they are lazy sods..........and have lots of Cylinders
Didn't know about the MV though.
Pretty sure by reading his post about the BMW twin he meant plain though when he said split.
Akunar sell still for the stoker pins anecdotally don't seem to have much luck with them here in the 4ts.
Out of interest with the MV what were the casting like, they always look so huge but where they well finished or just so so.

Was this pretty close
I think energy spent shaking stuff up and down could be better used to spin stuff round and round.( this is a bit of Jan and Frits paraphrased)

[ken seeber]

As a further indulgence, some more pics, some of a guy who lives in Perth. The others about Dr Gordon Blair of QUB. He, in fact, came to Orbital during his sabbatical, must have been around in 1998. He was in 4 stroke mode then. I lent him this scrapbook, while he was there. Semi got him out of 4 strokes for a bit.

[husaberg]

How fast? What bearings does the Ryger use?

Yeah, plain bearing cranks are cheaper for mass production, but shit themselves at the 1st hint of oil starvation - in perfomance applications..
& recips are generally limited by piston speed before rpm, anyhow..

I plucked 8000 rpm out of thin air
Have a look at a F1 engine crank and the answer is there.
Cameron covered it, you could probably google it from performance streetbike or whatever it called.

As a further indulgence, some more pics, some of a guy who lives in Perth. The others about Dr Gordon Blair of QUB. He, in fact, came to Orbital during his sabbatical, must have been around in 1998. He was in 4 stroke mode then. I lent him this scrapbook, while he was there. Semi got him out of 4 strokes for a bit.

Aussies Aye

Click on them three times