Kawi2strokes.com Forum

These frames crack anyways Mark....

do you have any examples for me to chew on?, or is it just a "hunch"?
and "Where" do you think it would crack? Old swingarm or new brace? Joints or mid tube? I dont want to do anything that has been proven NOT to work. But in an application like this, I dont believe the differences in metals are going to be a remote problem. If it was, I wouldn't even bother as I hate doing things over. Or maybe I'll let this bike be the "test-mule" to see if it will work?

I understand they are dissimilar metals, but stainless still flexes (especially this stuff as Ive crushed it in the vise and hammered it flat without cracks, and yes I understand that repeated flexing will work-harden different metals at different rates, but....)

If the welding is done correctly (penetration and correct filler 309), the welds themselves shouldn't be a problem?

If you've got a certified welder that can back it up then the plan sounds fine.
There are others that have not had such good results (the reason I mentioned it a few pages back) but who knows for what reasons.
It just wouldn't be worth saving less than $50 if it were me.
Besides you big time home remodeler's got all the cash anyway.

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There are only two types of motor sport racing:
Nitro and everything else
(Sometimes referred to as fast and slow)

Do lyou have a H2 swinger you can weigh Cody? That might be an easier way for a stronger swinger.

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Twist the throttle, tilt the horizon, and have a great time. What triples are all about...........

What is the total weight of the swingarm with the intended bracing?

Jim... who are the "others", and what were the results? I at least want some first person evidence of failure in this (or similar) application before scrapping it just on anecdotals alone.



I know the welds will be strong. I am not concerned by them.


John, nope, not using an H2 arm. It will be an S-arm that has been braced. Whether or not it is braced using stainless will depend on some emperical evidence showing that it failed in this application... Otherwise, I am happy to offer the emperical evidence once the thing hits the streets.

Too heavy! but still lighter than an H2 arm. I'll throw it on the scale (with added bracing and gussets) and report back later....

Thanks, I have a swingarm project that I have been working on. Haven't put it on a scale yet, but I am going to be in the "too heavy" catagory as well. Hopefully the cool factor will make up for the weight. When I am said and done, I am hoping for the swingarm, s hub and aluminum rim to weigh what stock h1 components do or less.

Cody, do you realy want to be the first to have a swing arm failier due to useing different metals welded together. I know you want lightness some some things should be left alone.
my 2cents

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If Satan had a bike and fed it cats it would sound just like my bike.

Cody,
I did read 1/2 dozen sites regarding welding stainless to mild steel before I posted.
Since alloy numbers are unkown, it would be difficult to pick the best filler wire, pre-heat or purge welding requirement for this application
I have not had great results TIG welding SS to regular; poor weld quality, eneven penetration, etc., then again I;m not certified.
Perhaps things have changed, but it was covered in HS metal shop and was considered to be not the best practice for applications under shear (at least in 1976).
Many (including Steve Chandler on this board) recommend only purge welding anything stainless including the chambers he made.

If you are not concerned about weld breakage the the point is mute consideingr this is a brace and not a load bearing member and the worst it could do is bend.
I think we can all agree that a 4000 series chrome molly steel is used in place of SS in ALL high performance frame applications including cars, bikes, and trucks for a reason.

If the weld doesn't break and the material strength is decent, the worst it can do is bend although that was the thing to correct in the first place.

_________________
There are only two types of motor sport racing:
Nitro and everything else
(Sometimes referred to as fast and slow)

I STAND CORRECTED!!!! And HOLY CRAP-ified

I just threw some stuff on the scale.

This braced S-Arm when all is said and done is well over 10 lbs, which is NOT GOING TO HAPPEN on this bike.

This is a comparison of 3 Stock Triple Swingarms all in equal states no bushings, spacers, etc

S-3 Swingarm, Bone stock is 7 lbs 12oz.
Late H1 Swingarm is 7lbs 8oz.
Early H2 Swingarm is 7lbs 4oz

The S-3 Swingarm is the HEAVIEST of the three and the H2 is the LIGHTEST!!!!!!

Most Surprising to me is that the early H2 ('72/'73) swingarm uses the same diameter tubing (34mm) and is only 1/4" longer from the center of pivot to the front of the axle slot... meaning while the H2 arm is actually LIGHTER, it is also longer and a hair wider at the pivot?? What the???

I cant see AT ALL how fitting an H2 (early) swingarm would help s-arm flexibility? Its virtually the same as the S-3 arm?

The later H2 arms have larger OD tubing I believe (dont have one on hand to check) but would need to be cut down length wise as Im not building a freaking drag bike...

This is all leading me back to another KZ650 Swingarm which uses 38mm diameter tubing....and If I remember is less than 1lb more than an early H1 swingarm (which I have yet to weigh), but still will be much less than this braced S-Arm.

The KZ650 arm was a very noticable improvement on the '70 H1, so it looks like Im heading that route now. (cause I have one.. )

what sucks now is that it is substantially wider at the shock mounts and this means either relocating original shock mounts on the frame? or upper spacers.. And then I'll once again need wheel spacers (Henry you out there? )

ugh, stuff can never be easy can it?