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Discussion Starter · #1 ·
I seek input about the necessity of the two-piece bracket which goes from the frame spine to the rear of the cylinder head, mounted just above the carburetor manifolds to the engine:



I think the whole affair would look better without it. It is puzzling to me because it is flat steel with one side straight and the other bowed and mounted with some pretty big hardware. How much bracing can it give? The head steadies on my old machines were much thicker and spanned across the two rocker box covers, mounted to a stud which went down into the head.

Thoughts on this, as in removal? Has anyone removed it?
 

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Discussion Starter · #4 ·
Yup, I read that. I started the thread thinking that someone has removed this piece and has run their bike for a while.
Somehow I just cannot see those thin strips of metal being vital to anything really. The engine really does not vibrate much at all, and much of the big motion is far below those spindly strips.

I suppose I will pioneer this using my Bonneville. If it's good enough for Jack Pine, it's good enough for me.:D
 

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I wouldn't do that, I think it could add too much extra strain on the cylinder head.

Imagine riding over a pot hole, the type that sends a shudder through you and the bike. As the frame contorts a little and only the front of the head is clamped in the frame, it could put added pressure on the head bolts and the two location dowels as the engine shudders. Those brackets could well stabilize the head enough to stop it twisting.

I have no proof of this as I've never tried riding without them but, head steadies have been used for years by motorbike manufacturers and they're not usually just for show. But it's your bike. :)
 

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I'm openminded. Just because Triumph put it there, doesn't mean it's really needed. However, Pieman has given you one good reason, and I've given you another, based on finite element modelling. In the scenario Pieman gives, you are applying torque to the jugs and you will eventually see a leaky gasket or sheared bolt in the head or cylinder walls. That's what happens with a 3 piece design.

But, that's the minor reason IMHO. After all the engine can pivot about those bolts, so they aren't really there to prevent pitching motions. However, note the way the parallelogram is set up by those uneven pieces. It's very effective at preventing roll, and you don't need much steel to do that. The roll comes the pistons going up and down. To demonstrate this, feel the vibration with the bike at 4000 rpm with the bolts tightened, and with them quite lose. Notice the difference ? That parallelogram acts as a very efficient vibration damper.

I can tell you the gusset at the bottom of the front rails does nothing really important. And the bike looks much better without it.

The Jack Pine bikes IMHO aren't meant for really riding. They are show bikes. Witness the blocked head oil cooler outlets in the head. And the frame bits that have been dispensed with. Looks cool and I've stared at the scram all month as it was the April bike on my BikeEXIF calendar.

But like the wise man says, it's your bike :eek:
 

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If you add the thickness of both of those peaces up thays alot more metal then you think it is it would pick the front of your car off the ground.I am with northern that jack pine bike is stupid some of the things the guy did are just plain dumb.
 

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Why not just have the Teutels design your bike,guys? That Jack Pine bike is a stying/performance exersize with no real thought to durability or longevity.

Suppose the engineers at Triumph(who hopefully are a lot better educated in this sort of thing than you and I)found that after rigorous testing,the frames developed cracks without this "superflous" bracing?

Maybe they found that,without the oil cooler,they'd have engine failures at tempurature extremes? Or at least reduced engine life.

I don't know.I'd just like to think that they didn't add all this extra bracing and oil cooling capacity to my bike just to make it more expensive and difficult to manufacture,more expensive to ship,heavier to ride,and more difficult and expensive to repair,etc.etc. All of which are Very Bad Things.

I'd really like to think Triumph is looking out for us a little bit.After all,think about it.They could have just left off all that "extra" expensive stuff and still sold it to us for the same price we paid anyway,right?

Hey,I'm just sayin'................
 

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Why not just have the Teutels design your bike,guys? That Jack Pine bike is a stying/performance exersize with no real thought to durability or longevity.

Suppose the engineers at Triumph(who hopefully are a lot better educated in this sort of thing than you and I)found that after rigorous testing,the frames developed cracks without this "superflous" bracing?

Maybe they found that,without the oil cooler,they'd have engine failures at tempurature extremes? Or at least reduced engine life.

I don't know.I'd just like to think that they didn't add all this extra bracing and oil cooling capacity to my bike just to make it more expensive and difficult to manufacture,more expensive to ship,heavier to ride,and more difficult and expensive to repair,etc.etc. All of which are Very Bad Things.

I'd really like to think Triumph is looking out for us a little bit.After all,think about it.They could have just left off all that "extra" expensive stuff and still sold it to us for the same price we paid anyway,right?

Hey,I'm just sayin'................
Yep thats how I look at it allso
 

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Discussion Starter · #14 ·
Why not just have the Teutels design your bike,guys? That Jack Pine bike is a stying/performance exersize with no real thought to durability or longevity.

Suppose the engineers at Triumph(who hopefully are a lot better educated in this sort of thing than you and I)found that after rigorous testing,the frames developed cracks without this "superflous" bracing?

Maybe they found that,without the oil cooler,they'd have engine failures at tempurature extremes? Or at least reduced engine life.

I don't know.I'd just like to think that they didn't add all this extra bracing and oil cooling capacity to my bike just to make it more expensive and difficult to manufacture,more expensive to ship,heavier to ride,and more difficult and expensive to repair,etc.etc. All of which are Very Bad Things.

I'd really like to think Triumph is looking out for us a little bit.After all,think about it.They could have just left off all that "extra" expensive stuff and still sold it to us for the same price we paid anyway,right?

Hey,I'm just sayin'................
I take it that you think it's a bad idea? :D
All very true, however, bikes do get chopped, bobbed, sliced, diced, and curled in all sorts of ways, many which leave them still rideable.
I am not going to remove them, though. It was only a thought brought upon by my affection for motorcycles with as little on them as necessary.
 

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So that little rectangle's really called a breastplate? Cool. Makes me want to paint some knight's coat of arms thing on it... Something with crosses, swords and a lion's head.


Or not.
 
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