Lesson's Learned / Postmortem / Advice

[mxaniac]

In the middle of putting a 2003 500 engine in a 2006 KX450f frame.  Anyone have something to share they wish they would have known to begin with?

Thanks,

Rich

[Twosmokerfan]

Hi Rich,

One of the big things I learnt was (obviously), measure twice, cut once.

This website is the best for a huge amount of knowledge, so take your time and read and seach the threads (I couldn't have done it without the info here.

Do a lot of mock ups and keep re-checking your measurements.

When it comes to boring the KX500 rear mount, take it to a engineering shop with a drill press.  Get them to get the dummy alignment with a 15mm drill, bolt the engine down, then go for it with the 17mm.  I drilled it with a 17, and used an adjustable hone to take a very small amount out of the bore to make the bolt go in easier.

I was lazy and bought the SH exhaust with a Q series muffler, so my bracket dimensions are not the same as everyone elses.  The SH hose kit is very cool, but I did some mods to it to be able to take the existing KLX450 radiators with only one hose outlet modification.  Worked a treat and I can still use the aftermarket radiator protectors.

I used the original lower brackets of the KLX450 (same frame as yours, or close enough to it).  I didn't grind any of the frame at the rear engine mount, I just used a bottle screw jack and pressed it out about 2mm to get the engine and swingarm in with the bolt.  It is a tight fit.

Frame rails from JFAB are very popular, but I ended up making inserts with internal spigots.  Personal choice.

Take you time to read everything on the site.  It is excellent.
TSF

[mxaniac]

Thanks for the input.  I bought a work in progress and had to redo much of it because it was originally intended to be a hill climber and my intended use is MX.  With that in mind I redid the frame tubes, motor mounts, radiators, coil mounts, pipe mounts, silencer mount, head stay, and airbox.  In retrospect I wish I would have:

Engineered (I am a mechanical engineer) the frame changes.  As it is I pretty much hand fit the components but the end result looks cobbled compared to some peoples works of art.

Started with a later model frame.  The 06 suspension is so bad someone from Kawasaki should commit Hari-Kiri over it.  I don't even consider it rideable.  Changes were made after 06.

I did use 7005 aluminum from fairing (I would avoid nova) and treated it for 6 hours at 200F then 4 hours ant 320F to harden it.  I originally had every weld redone except 1 from the original project but that weld broke after 15 minutes.  I would advise anyone doing this to use 7005 AL with 5356 filler rod and tig weld their frame then bake it like I did to precipitation harden it.

[jBernard]

mxmaniac,
why not use a 6000 series and avoid all the issues with welding. i thought that 7000 series was pretty much unweldable?

[mxaniac]

mxmaniac,
why not use a 6000 series and avoid all the issues with welding. i thought that 7000 series was pretty much unweldable?

Something like 6061 needs to be baked in an oven at very high temperatures to precipitation harden it (as high as 1000 F), otherwise it has extremely diminished properties at the welds.  7005 is engineered to harden at much lower temperatures, you can do it in a powder coat oven or a thermal chamber.  It is highly weldable, some contend easier than 6061.  The hard to weld materials you are referring to are typically 7075 and 2024.

[jBernard]

Good info thanks! Do you think the heat treating is necessary though? I think the stck rails are 6063. I don't think to many on here have had any lower rail failures and the one crack I did see seemed to be from a engine bracket mount that didn't distribute the weight enough.
Also, would the heat treating of the 7000 series lower rails negatively impact the surrounding 6000 series of the rest of the frame since they may need to be processed differently?

[mxaniac]

Good info thanks! Do you think the heat treating is necessary though? I think the stck rails are 6063. I don't think to many on here have had any lower rail failures and the one crack I did see seemed to be from a engine bracket mount that didn't distribute the weight enough.
Also, would the heat treating of the 7000 series lower rails negatively impact the surrounding 6000 series of the rest of the frame since they may need to be processed differently?

The properties of 6000 series aluminum completely turn to crap after welding.  Yes heat treating is beneficial.  Especially where the downtube is cut and the Y moved up.

I've not found a definative answer on what the stock frame is made of, where did the 6063 come from?  6061 in something like a T4 condition is much stronger than a 6063.

[jBernard]

jfab uses 6063.
i did a bit of research and bending 6061, especially T6 which is 99% of whats out there, wont handle the bend of the rails without cracking/deforming. 6063 is architectural grade and handles the forming much easier. welds easy as well.
also, 6061 seems to loose up to 80% of strength at the weld site whereas 6063 while lower tensile and yield strength will only loose up to 30%. i think the reasoning behind the 6063 is thats yes it looses quality at the weld, but with proper design and gusseting it is strong enough and doesnt need to be treated after welding.
i'll be bending mine out of 6063 within a week or so, hopefully turns out fine!