Topic: project 71 cb750 with 330 wheel convertion

[333]

Any time you take even the slightest angle of a turn, it will rob considerable power.  And your drawing shows much more angle than is on the device we're talking about.  But even with a milder angle, there is still loss.

Where's it going to rob the power? Friction in the flexing chain, friction from having to spin another idler, and what else?

Not friction, but a loss of power from the change of direction.  Say you are pulling something with a long rope.  You come to a turn, where the rope will have to go around something, a tree perhaps.  Even if you grease the rope and tree, you still can't get a straight pull on the weight, making it harder.  This same phenomenon can also work for you if, say you were lifting something heavy off the ground.  it will make the weight harder to pull back.

[mystic_1]

 it works great.. the arm that is on the jack shaft has a bearing, maybe that is why its trown u guys off.. the cylinders only have 4 inches of travel. the pic u describe the jack is off alot it more closer to where the swingarm bolts to the frame

I gather, then, that you've swung the arm through it's entire arc with that setup in place?  Unless the two pivots are in the same place, you'll get some stress at the very least when the arm is at max travel.  The shorter arm will want to move through a different arc than the main swingarm, might put a lot of stress on the welds where the tensioner support meets the swingarm.

mystic_1

[edbikerii]

So, I did some research on jackshafts.  I think I'm starting to understand what you are up to now, 631.

I see that other jackshaft applications have the jackshaft attached to the swingarm, and NOT pivoting.  The front chain allows the jackshaft to move up and down in an arc around the drive sprocket (transmission output sprocket?) as the suspension compresses and extends.

The distance from the jackstand center to the axle center is CONSTANT, regardless of the suspension compression.

I see from your original pictures that the tensioner sprocket (or wheel down the road) and the arm it is attached to were added on to the swingarm later, just to keep the chain from dragging on the swingarm.  The adjustment is done once, as a maintenance task, and there is no spring loading or dynamic pivoting on that tensioner arm.

I think this picture illustrates the design well:





These Hayabusa guys are sick modifiers.  They've done jackshafts, and they've evolved past that to "outside drives".  Check it out:

http://www.hayabusa.org/forum/busa-mods/116798-jackshaft-conversion-osd.html

[Frankenkit]

I posted that link a couple pages back.

just pickin.  You know I love ya, Ed.

[edbikerii]

I posted that link a couple pages back.

Yep, I just went back and looked, and sure enough, you sure did.  I checked out for a while because the thread seemed to be going downhill fast.

just pickin.  You know I love ya, Ed.

Hey, you had your chance.  That ship has sailed, baby.  You're stuck with so-and-so now.

[333]

That 'Busa kit probably gets away with the jack shaft placement by having the counter shaft, jack shaft, and pivot point all in a straight line when the suspension is at rest.

[Syscrush]

Not friction, but a loss of power from the change of direction.  Say you are pulling something with a long rope.  You come to a turn, where the rope will have to go around something, a tree perhaps.  Even if you grease the rope and tree, you still can't get a straight pull on the weight, making it harder.  This same phenomenon can also work for you if, say you were lifting something heavy off the ground.  it will make the weight harder to pull back.

If you're pulling in a different direction from the displacement, then yes, you'll have to increase the force in the rope in order to reach the same force in the direction of displacement (the only force that counts when calculating work & power).  So if you're pulling a train on a track, it will be much more efficient if your rope is parallel to the tracks than if the rope is at 45 degrees to the track.  If the rope was perpendicular to the track, then no amount of force would move the train (until you derail it).

However, NONE of this has anything whatsoever to do with the case of a chain connecting sprockets, because the chain always applies a torque to the sprocket from the most efficient direction - tangential to the outside edge, via the teeth.

If you ignore the effects of friction, the two cases in the diagram are exactly the same in terms of power transmission.

[mystic_1]

Here's an illuistration, as you can see the swingarm and the idler arm will pivot in different arcs.  As deflection increases, the differences in the arcs increase.

mystic_1

[Terry in Australia]

Well I thought I'd leave Frank alone for awhile and instead post some pics of the jackshaft I had to build to twin-engine my bicycle last year.

It's possible that jackshafts do rob Hayabusa's of power, but I'm lucky, my bicycle didn't have any power to begin with! It will do around 50 MPH now, but we're hoping that with some "tuning", we'll have it doing 80 by the time we get it on the salt!

Oh, and no, it hasn't been photoshopped, my workshop is really this messy!

[Industrial Cafe]

your filters look like the skull from The Punisher.

[Frankenkit]

you need a saddle like this on that bike.

[mlinder]

That bicycle is pretty exciting, Terry! Any videos of it running?

[Terry in Australia]

That bicycle is pretty exciting, Terry! Any videos of it running?

G'Day Mark, no I didn't have a video camera when I built it, it's currently residing in my cousins shop 200 miles away in my home town, but my son's got a fancy $5000 movie camera now so when I collect it from my cousins house I'll film it and post it here.

My cuz and I took it out to a quiet country road a couple of weeks ago and had a great time on it, the brakes are just about destroyed now, they were never designed to haul a bike down from these sorts of speeds, but at least they don't rub on the rims any more, ha ha! Cheers, Terry.

you need a saddle like this on that bike.

Ha ha, as someone else here mentioned Kit, that seat costs more than I paid for the bike!

your filters look like the skull from The Punisher.

We took the filters off for the last run IC, and I couldn't believe how just removing a couple of filters could make it rev out so much more, they'll definitely stay off for our "Worlds fastest Bicycle" attempt at Lake Gairdner in March! (if they'll let us run it)  

[Industrial Cafe]

We took the filters off for the last run IC, and I couldn't believe how just removing a couple of filters could make it rev out so much more, they'll definitely stay off for our "Worlds fastest Bicycle" attempt at Lake Gairdner in March! (if they'll let us run it)  

make a video of that too, that would be awesome man.

[754]

Dont know about ozrules, but..at Bonneville you need a steering damper..

How do you adjust the primary chains?..shims under the bearing blocks?

[333]

Not friction, but a loss of power from the change of direction.  Say you are pulling something with a long rope.  You come to a turn, where the rope will have to go around something, a tree perhaps.  Even if you grease the rope and tree, you still can't get a straight pull on the weight, making it harder.  This same phenomenon can also work for you if, say you were lifting something heavy off the ground.  it will make the weight harder to pull back.

If you're pulling in a different direction from the displacement, then yes, you'll have to increase the force in the rope in order to reach the same force in the direction of displacement (the only force that counts when calculating work & power).  So if you're pulling a train on a track, it will be much more efficient if your rope is parallel to the tracks than if the rope is at 45 degrees to the track.  If the rope was perpendicular to the track, then no amount of force would move the train (until you derail it).

However, NONE of this has anything whatsoever to do with the case of a chain connecting sprockets, because the chain always applies a torque to the sprocket from the most efficient direction - tangential to the outside edge, via the teeth.

If you ignore the effects of friction, the two cases in the diagram are exactly the same in terms of power transmission.

No, there is loss of power in the difference of angle that the tensioner makes between the jack shaft and the wheel sprocket.  It's not as severe as the drawing suggests, and friction is minimal at best because the tensioner is either greased or has a bearing.  But the pull is being applied to the tensioner, not the wheel sprocket.  The proof of what I'm saying is the fact that if the tensioner arm didn't have a solid hold on the other end, it would be forced down.  And I'm not so sure how solid it really is.

[BLUE71TURBO]

Hey Terry,  you need to run some K&N filter pods or some velocity stacks for maximum flow. 

[Turbogrimace]

Hey terry,

I built a bike with one of those engines.  I ported the intake and the exhaust and made a custom exhaust for it.  Those mufflers yoiu are running in the picture rob so much power.  When I first got the bike together with everything stock, it had a max of 25.  After the mod's I was hitting 40 mph.  The 12mm carb can be upgraded as well, and there's a shop online that sells expansion chambers.  Thatlle get you where you want to go.  The engines also have pretty low compression.  Milling the head will do wonders for power.

That looks really nice though.  I sold the one I built to a friend of mine and he was considering doing the double engine thing too.  Running them 90* out of sync to get a nice sound.

[Terry in Australia]

Dont know about ozrules, but..at Bonneville you need a steering damper..

How do you adjust the primary chains?..shims under the bearing blocks?

G'Day Frank, I've got to go to a meeting of the Dry Lake Racers Association (DLRA) next Sunday, so I'll find out then what I need to run it, but I think the rules are the same for both Oz and the US. Either way, no biggie, I can adapt a small motorcycle steering damper to fit it, I guess.

To adjust the primary chains, I just loosen off the whole jackshaft assembly and slide it up the frame tube until they're tight. That also tightens the final drive chain, but I've purposely made it longer for this reason, and you'll see that I've made a spring loaded chain tensioner with a wheel that I machined from teflon rod, to take up the slack. "Typical 8th grade metalworking" I know, but it works. 

Hey Terry,  you need to run some K&N filter pods or some velocity stacks for maximum flow. 

Ha ha, possibly mate, I'm just the fabricator, my cuz is the tuner, but I've been checking out some hop up parts on EBay so I'll show him (he's not "computer Savvy") and see what he thinks?

Hey terry,

I built a bike with one of those engines.  I ported the intake and the exhaust and made a custom exhaust for it.  Those mufflers yoiu are running in the picture rob so much power.  When I first got the bike together with everything stock, it had a max of 25.  After the mod's I was hitting 40 mph.  The 12mm carb can be upgraded as well, and there's a shop online that sells expansion chambers.  Thatlle get you where you want to go.  The engines also have pretty low compression.  Milling the head will do wonders for power.

That looks really nice though.  I sold the one I built to a friend of mine and he was considering doing the double engine thing too.  Running them 90* out of sync to get a nice sound.

Hey thanks mate, and you're right, those ports are tiny, so my cuz will open them right up, and we'll look at taking some metal off the heads too. I'll see if I can find that online expansion chamber guy and buy some, (I'd make some myself if I understood the theory) I've ripped the guts out of the OEM mufflers, but expansion chambers would be brilliant! Cheers, Terry.

[Kframe]

Is that exhaust gonna create clearance problems while attempting turns?   
-K

[BLUE71TURBO]

Is that exhaust gonna create clearance problems while attempting turns?   
-K

im sure it will trow sparks.

   
   Exhaust is definitly a problem there.

[Industrial Cafe]

are they home made? I've never seen drag pipes that far away from the frame.
 I'd do some crazy high pipes on that bike.

[vanillagorilla]

 
   Exhaust is definitely a problem there.

but its crunk. looks first. then rideability. obviously...

are they home made? I've never seen drag pipes that far away from the frame.
 I'd do some crazy high pipes on that bike.

You are still asking questions like you'll get answers...

[edbikerii]

So, 631, thanks for posting those new pictures.  The new pictures show the suspension extended more, correct?

That proves something:  Either there is only one pivot point, or the pivots are concentric.

I'm leaning towards there being only a single swingarm pivot.  Is that correct, 631?

The tensioner seems to have moved slightly closer to the swingarm with the chain under more tension.  Is that also correct, 631?

Is that tensioner spring-loaded, too?  Will it return to the old position when the suspension is compressed?  Does it do that by being spring-loaded somehow, or does it pivot against the frame or something?  If it pivots based on geometry rather than a spring, was it difficult to come up with the correct ratio?  Or is that still being fine-tuned?

Thank you,

Ed

[Stev-o]

Is that exhaust gonna create clearance problems while attempting turns?   
-K

im sure it will trow sparks. Will look cool at night!