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Old 08-11-2012, 07:24 AM   #91
Krasniewski OP
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Quote:
Hve you done anything about your front down tubes yet.
From page 2:





It's my understanding that the spine carries most of the load, not the engine cradle. Reference the stock Ninja frame that doesn't even cradle the around the bottom of the motor - it's just the spine (well, split spine in this case?) and the stressed motor.

Unless I find a stress fracture somewhere - the tubes aren't going anywhere. I'm very confident in them. I know the welds are ugly, but I'm sure they're solid.

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Old 08-11-2012, 02:01 PM   #92
DRjoe
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Ok

Just don't go jumping the thing at speed.
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Old 08-11-2012, 05:25 PM   #93
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Originally Posted by DRjoe View Post
Ok

Just don't go jumping the thing at speed.

Thanks, mom.
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Old 08-12-2012, 12:08 AM   #94
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Eek frame design 101

Quote:
Originally Posted by Krasniewski View Post
From page 2:





It's my understanding that the spine carries most of the load, not the engine cradle. Reference the stock Ninja frame that doesn't even cradle the around the bottom of the motor - it's just the spine (well, split spine in this case?) and the stressed motor.

Unless I find a stress fracture somewhere - the tubes aren't going anywhere. I'm very confident in them. I know the welds are ugly, but I'm sure they're solid.
I am sorry to tell you that you are mistaken about the frame loads.
The "spine" as you call it, or backbone (top tube) is only one path for the transfer of loads.
You are correct that a properly designed frame does NOT require an under engine cradle.
Because the frame gets the required triangulation from other tubes and/or the engine mounting.

The EX uses the engine as part of the frame and the engine castings are designed to carry the loads.
As you understand as you said it is a stressed engine.
The KLR frame does NOT use the engine as part of the frame so it needs a different design.

Your modification to the frame is definitely NOT as strong as it was before because of the way you added the new cradle tubes. However, IF you make good solid engine mounts to use the EX engine as part of the frame by tying the steering tube through the engine to the swingarm mounts you will recover a lot of the lost strength. Maybe enough even... If your engine mount points are well engineered to carry the frame loading and are extremely precise bolt line-up. No oversized holes allowed!

In frame design, think of triangulation, or even better, pyramids, 3 sided pyramids with each corner and the top as the fixed points. It can't be bent, twisted, or distorted without huge forces. A typical motorcycle frame with a double cradle is actually a poor compromise because of packaging an engine. A much better design is the perimeter frame where the load path from the stem to the swingarm can be almost in-line and then another tube (each side) can either be above or below the engine and going from the stem to another tube to create a triangle. Does that make sense? It is late and my brain is tired. Then the two frame side triangles are cross connected and braced.

Your frame mods have broken the load path that went down the front tube and then split into a double cradle under the engine forming a triangle. It would have been MUCH better if you had connected your new cradle at the front tube in one place forming a bent triangle under the engine similar to the stock frame. By putting a cross tube horizontal and then connecting your cradle tubes to it you have turned the cradle into a bent rectangle which has very little resistance to twist. Picture an open cardboard box and how easy it is to deform it by pushing in on any corner.

A motorcycle frame is designed to handle a lot of twist not just supporting the weight of the engine and tying the stem to the swingarm.

I strongly encourage you to rethink and rebuild your frame modification.
It can be done correctly without major expense or time.

First, cut out the tubes you added and then have the correct size TUBING (not pipe) bent to shape that will meet together on the front down tube at whatever height you need for engine clearance (oil filter, etc.). It would also be very good to get short (2"-3") tube that is a tight fit inside the frame tubes to act as internal sleeve stiffeners for the weld joint. Drill a hole through the frame tubes and puddle weld the sleeves in place before welding the new tubes to the existing frame tubes.

Others have successfully modified the KLR frame so learn from them.
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Old 08-12-2012, 12:42 AM   #95
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what he said
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Old 08-12-2012, 06:05 AM   #96
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Quote:
Originally Posted by JagLite View Post
I am sorry to tell you that you are mistaken about the frame loads.
The "spine" as you call it, or backbone (top tube) is only one path for the transfer of loads.
You are correct that a properly designed frame does NOT require an under engine cradle.
Because the frame gets the required triangulation from other tubes and/or the engine mounting.

The EX uses the engine as part of the frame and the engine castings are designed to carry the loads.
As you understand as you said it is a stressed engine.
The KLR frame does NOT use the engine as part of the frame so it needs a different design.

Your modification to the frame is definitely NOT as strong as it was before because of the way you added the new cradle tubes. However, IF you make good solid engine mounts to use the EX engine as part of the frame by tying the steering tube through the engine to the swingarm mounts you will recover a lot of the lost strength. Maybe enough even... If your engine mount points are well engineered to carry the frame loading and are extremely precise bolt line-up. No oversized holes allowed!

In frame design, think of triangulation, or even better, pyramids, 3 sided pyramids with each corner and the top as the fixed points. It can't be bent, twisted, or distorted without huge forces. A typical motorcycle frame with a double cradle is actually a poor compromise because of packaging an engine. A much better design is the perimeter frame where the load path from the stem to the swingarm can be almost in-line and then another tube (each side) can either be above or below the engine and going from the stem to another tube to create a triangle. Does that make sense? It is late and my brain is tired. Then the two frame side triangles are cross connected and braced.

Your frame mods have broken the load path that went down the front tube and then split into a double cradle under the engine forming a triangle. It would have been MUCH better if you had connected your new cradle at the front tube in one place forming a bent triangle under the engine similar to the stock frame. By putting a cross tube horizontal and then connecting your cradle tubes to it you have turned the cradle into a bent rectangle which has very little resistance to twist. Picture an open cardboard box and how easy it is to deform it by pushing in on any corner.

A motorcycle frame is designed to handle a lot of twist not just supporting the weight of the engine and tying the stem to the swingarm.

I strongly encourage you to rethink and rebuild your frame modification.
It can be done correctly without major expense or time.

First, cut out the tubes you added and then have the correct size TUBING (not pipe) bent to shape that will meet together on the front down tube at whatever height you need for engine clearance (oil filter, etc.). It would also be very good to get short (2"-3") tube that is a tight fit inside the frame tubes to act as internal sleeve stiffeners for the weld joint. Drill a hole through the frame tubes and puddle weld the sleeves in place before welding the new tubes to the existing frame tubes.

Others have successfully modified the KLR frame so learn from them.
I'm glad he typed it up- I was going to say much the same last night but it was just too damn late.

Do HIGHLY suggest you follow his advice, and definitely sleeve the frame junctions before welding, and rosette weld (drill hole and "puddle weld" it) before welding all the joints.

This is quite similar to building a rollcage. The way to go when you are building a cage is, as here- triangulation.
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Old 08-12-2012, 07:47 AM   #97
Krasniewski OP
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Noted, thanks for all the concern and input.

Maybe someday... I'm still completely unconcerned.
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Old 08-13-2012, 02:03 AM   #98
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Mate there is a huge risk that the frame might give way.
What happens if that frame breaks when your hooking into your favourite high speed corner or going down a rough track at speed.

I'm sorry to be blunt but not only is the tube work you've done not up to scratch but your welds are no where near good enough for frame work. From the pics it looks like you have a lot of slag contamination and inconsistant penatration which will premote sudden cracking through the weld and as your frame design is relying on weld strength and not trianglation then you probably wont get a warning of a stress fractures apear but a complete and sudden faliure.


Please for your own safety please have a fabricator look at it and design some proper down tubes.
You've already done all the hard work it would be easy for a fabricator to knock up some nicely bent down tubes and weld them in there for you.


Sorry about the bad spelling.
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Old 08-13-2012, 05:10 PM   #99
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EDIT: Current close up pics of the frame welds:








Sounds like a challenge... now I'm just going to TRY to break the frame.

Anyhoo - I'm going to go and find some gas tank sealant.

Don't know I'll be able to make my dyno tomorrow.

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Old 08-13-2012, 05:38 PM   #100
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At least the good news is that some parts are in...

A much wider, shaplier seat for a much wider, shaplier butt.



And rubber can really keep you out of trouble... unless, of course, your frame breaks...

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Old 08-13-2012, 05:40 PM   #101
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I hate to jump on the bandwagon here as a fellow builder but I would second/third what has been said before. Your single backbone frame has been cut in half and replaced with butt welds that look suspect to begin with. I'm not being a critic to pile on, I'm simply speaking as someone who has done quite a few frame modifications.

I have made mistakes, we all do. I grimace every time I have to pull out the grinder and sawzall and cut off tubing work I spent hours patiently fabricating. But my rationale is my two beautiful children. And wife I guess

Your lower frame work really needs attention. Not when it breaks, but right now. Find someone with a tubing bender and some 1.25" DOM tubing and make some really beautiful bent down tubes. Best part is no welds other than the top and bottom joints.

I know you are rightly proud of what you have accomplished, it's not many that come through the other side of a project like yours. And everything else looks great. Just, PLEASE, take care of those tubes before you forget about things and six months later your posting up in face plant.

If you can't find anyone else local, send me a PM and I'll bend them for you for shipping. But it's much better to have the bike on site to get quality bends.
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Old 08-13-2012, 05:51 PM   #102
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Originally Posted by sailah View Post
If you can't find anyone else local, send me a PM and I'll bend them for you for shipping. But it's much better to have the bike on site to get quality bends.

Kind words and a very nice offer - thanks.

Taken into consideration - I'll take another look at her with some free time coming up soon. It's just hard to want to change much in that area when I'm actually riding the bike and it seems fine. But I guess that's a poor judge of what's right.
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Old 08-13-2012, 08:16 PM   #103
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Kras:

Bear this in mind:
When you weld, the weldment itself is stronger than the metal you're welding to- BUT- you also retemper the frame and this is certainly NOT a good thing. This is specifically why you want to minimize welds on load-bearing members, and if you must weld you want to reinforce the joint in such a way as the weld isn't taking the load directly. This is why you sleeve a joint when you weld a rollcage if at all possible.

It's a great build- don't lose sight of doing it right just because you've got some seat time. :)
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Old 08-17-2012, 01:36 PM   #104
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Question Confidence required!

Quote:
Originally Posted by Krasniewski View Post
Noted, thanks for all the concern and input.

Maybe someday... I'm still completely unconcerned.
Confidence in our equipment is essential to be able to enjoy our activities.


Can you imagine a skydiver not having confidence in his/her parachute packing?


A race car driver wondering if the pit crew remembered to tighten the lug nuts as he hits 180 mph??


But we can be confident and unconcerned about our equipment and be WRONG.






I am sure this rider was unconcerned about his bike as he practiced his skills....



















I think the lack of safety gear attests to his confidence, and/or lack of intelligence








Another example of misplaced confidence is this girl:







She is trusting her life to her friend's riding ability to keep her safe.

Maybe she has ridden with him many times with not the slightest fear.

Perhaps she has watched him go around this corner again and again before he invites her to ride along.





However, she should have been concerned.....






Take a look at this picture and what do you see?

Front wheel has lost traction and they are going down.
In less than one second they will be sliding on the pavement with the weight of the bike on their left legs.
Notice her left foot? She has probably lost most of her left toes already and she doesn't even know it yet.
This is the small version of the picture, the large image shows her foot clearly twisted sideways on the asphalt.

Maybe the rider had taken this corner a hundred times at this speed and even faster, so he was confident in his ability to take her for a safe thrill ride. Perhaps he forgot to take into account the extra weight on the rear tire that made the front tire light and lose traction. Maybe he just got on the throttle too soon or too hard. Whatever the reason, the result is the same, blood, guts, gore, and scars for life, at the very least.



Sometimes there is no warning when things go wrong brother.
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Old 08-17-2012, 01:51 PM   #105
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Yeah yeah yeah... thinking about gusseting the front top T until I do major rework.

Anyway, front sprocket nut is stuck on - not a left hand thread from what I've read. Washer is flat, used a pneumatic impact wrench (could use more air pressure - my compressor sucks), soaked in WD40. I think the previous owner used a lot of permanent strength loc-tite... I applied a bit of heat to the nut as well, but that may have been a bad idea...

Anyway - dowloaded the progam for the PCIII - I may play with the maps a bit this weekend. It's been crazy busy at work and at home the last week, but off on vacation soon!

Bought another stock tank to try to modify similarly to what I already did, but tig it this time and keep it looking better all around. That'll get worked on weeks from now though...
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