//ArrowChat Code
Page 1 of 2 1 2 LastLast
Results 1 to 15 of 16

Thread: My last ATC500R Frame Conversion build - October of 2023.

  1. #1
    Billy Golightly's Avatar
    Billy Golightly is offline Always finding new and exciting ways to not give a hoot in hell Catch me if you can
    Join Date
    Sep 2002
    Location
    Live Oak, FL
    --
    15,066
    Blog Entries
    14

    My last ATC500R Frame Conversion build - October of 2023.

    A long time ago (too long ago, now) I was contacted about doing one more ATC500R conversion frame, like I use to do years ago. It had been more than 10 years since I had built the last one. Back in the day I built quite a few of these after I built one initially for myself. I would like to think I got pretty good at figuring out how to do certain aspects of these builds better or more effective, or at least for myself as a builder I did. Along the way I had quite a few trials and tribulations in personal life that delayed the work longer than I anticipated, but I've finally got it wrapped up and figured I'd make a post here about the process with some pictures and some commentary about the process and building these things.


    There are a lot of threads and posts here from back in the day on doing these conversions. Generally speaking there are two accepted ways to do it utilizing the 250R frame (And of course using the existing CR500 frame is another method, I've built one that way before too).

    One - heavily dimple/dent/bend most of the original bottom frame cradle, and cross bar the bottom shock linkage mounts to because the CR500 engine is lower slung, than a 250R engine, and is of course taller since its double the engine CC size...

    Two - is removing and rebuilding the entire engine cradle, and new front mounts, and something that I think I kind of originated, is also cutting out the bottom shock linkage cross bar, and welding back in one that has a bend in it, and putting the bottom shock linkage tabs back onto it. This makes it where you only require two small notches/dents to clearance the back furthest corner of the engine, and also the shifting shaft and shifter.


    And with that I'm going to share some pictures and commentary on what i did with this one, and maybe someone will find it useful for building their own again in the future along with researching some of the other threads and resources here.


    First off, It's not a good idea to start with a frame that is this rusty...

    Click image for larger version. 

Name:	i-47S7FNX-X4.jpg 
Views:	119 
Size:	1,019.6 KB 
ID:	270879




    I can't emphasize enough - all of these frames are now the better part of 40 years old. FORTY YEARS OLD. Even the best, most original looking "barely touched" frames will have internal rust and degradation on them just by humidity. The metal had no paint or coating on the interior of the tubing. It is extremely probable that you're going to have rust and issues welding new steel to this old stuff. When you cut a tube you're going to have bits of rust flake dust and dirt fall out onto the shop floor. That's part of the challenge with this process.

    Click image for larger version. 

Name:	i-djZMd72-X4.jpg 
Views:	116 
Size:	948.2 KB 
ID:	270880Click image for larger version. 

Name:	i-bbzBZd5-X4.jpg 
Views:	114 
Size:	1.02 MB 
ID:	270881

    Okay, so in these two pictures you can see how you cut the frame cradle rails out, and the shock linkage cross bar, and you'll see the bent piece of 1.250 tubing I have that'll go in it's place. You'll also see I've cut loose the original shock linkage tabs and will re use and weld them onto the new cross bar. After doing enough of these way back in the day, I bent up and made "templates" with scribe lines and the # of degrees for the bends for this piece and the bottom frame rails that allowed me to duplicate and bend up new ones much much quicker than trial and erroring every build on where to bend the tubing, what lengths, etc. I had kept those template bends all these years or I wouldn't have even tried to take this on.

    I always have started these builds by doing a few things. One, I just cut the cradle rails off right above the front motor mount bosses that are welded into the frame. Two, I cut the bottom cradle rails off about flush with this shock linkage cross bar, and then then I cut the cross bar out. Then I run the swingarm bolt back through the frame, through the back of the CR500 engine, and slide the engine all the way over to the left (Sprocket side) to get chain alignment. Then, and here is the kinda neat thing, you hang the CR500 head-stay bracket by the original ATC250R head stay mounts, and it puts the sprocket to swingarm bolt centerline almost exactly level, which is important for suspension travel and suspension "climb" whenever you gas the throttle. This is one of the other advantages of this method, vs just putting the motor in most of the original frame tubing, the sprocket gets mounted too high up because the motor can't hang down level where it needs to be, basically. Anyways, once the swingarm bolt is in, and you're hung from the head stay, you can basically start building everything else around that.

  2. #2
    Billy Golightly's Avatar
    Billy Golightly is offline Always finding new and exciting ways to not give a hoot in hell Catch me if you can
    Join Date
    Sep 2002
    Location
    Live Oak, FL
    --
    15,066
    Blog Entries
    14
    Click image for larger version. 

Name:	i-RfCSHZ3-X4.jpg 
Views:	114 
Size:	800.7 KB 
ID:	270882Click image for larger version. 

Name:	i-9f6kpMx-X4.jpg 
Views:	114 
Size:	1.29 MB 
ID:	270883

    Top picture, if you study this you'll see my "Jig" is bolted into the frame at the swingarm pivot bolt, and I have the bottom shock linkage tabs basically slid over it, and you'll see the little arm I have for the bottom chain roller also. I think I may have some better pictures of the whole thing I'll share later on if I did take some, but this thing is basically a piece of old swingarm cut off right at the pivot, so it utilizes that original honda swingarm part at the swingarm bolt pivot. Over the years I put Delrin bushings in it so I didn't have to keep fiddling with the dust caps and needle bearings that were the OEM setup when you pulled this thing in and out a million times on a build. Right onto that swingarm I have a piece of tubing and a lathe turned boss that fits in where the top shock mount is on the frame, and then of course another for the bottom linkage mount, and the chain roller mount that you see in the picture. The neat thing about this is, when I bolt it in, again, everything is in place. I just have to build and connect onto it basically, and it makes sure the geometry and stuff does not change from the original mounting points and positioning. You will have some frame spring in other places, but this at least allows you to keep everything where it needs to be.

    Second picture, this is some of my bent up bottom frame rails. There are 3 different bends there as you can see. One of the biggest challenges with the CR500 conversion is clearance on everything, everywhere. allowing clearance in the bottom of the rail for the shifter to move up and down without having to cut a big notch in it, is one of the reasons they are bent this way. They don't necessarily sit "flat" on the bottom like a 250R cradle or regular dirt bike cradle does, because there isn't a way to do that without significantly notching in the frame for the shifter clearance. I use 1.125 tubing here, as it is a very close match to the OEM metric tubing, but I go thicker. I think the original OEM tubing was about .065 or something close to it, before it started rusting and getting even thinner. I use .083.

    Click image for larger version. 

Name:	i-T3kHfF8-X4.jpg 
Views:	112 
Size:	991.0 KB 
ID:	270884

    This is a picture of the new shock linkage cross bar tacked into place, and you can also see more of my jig I was talking about. You can also see, looking into the frame, what the insides of the original tubes look like. And this was definitely not the rusty one I had in the first picture, this is a much much much better looking one! There is so much hand fitment, grinding, filing, and fitting on doing this. There really is not any ways to make the pieces fit exact. Having the tubes prebent saves a lot of time, but there is no way I've found to reasonably speed up the fitup during this process because of all the little variations and even in how you cut the original frame also has a factor it. I also had to weld on a whole new swingarm pivot plate and hole on one side of this fram because it had been cut off sometime in the past, I'm assuming to remove a stubborn swingarm bolt that had been frozen into place.

  3. #3
    Billy Golightly's Avatar
    Billy Golightly is offline Always finding new and exciting ways to not give a hoot in hell Catch me if you can
    Join Date
    Sep 2002
    Location
    Live Oak, FL
    --
    15,066
    Blog Entries
    14
    Next step for me is machining and turning on the lathe some bushings/slugs that will fit inside the original portion of the frame in the wishbone area, welding those in, and then that allows me to "slip fit" the new bent up round tubing over those, and then allows me to weld those on also once they're positioned where they need to be. On an early attempt years ago I just made these solid steel without drilling the hole through them, but welding and heat temperature wise I had a lot of challenges, I would blow away my thin tubing before I had the inner slug hot enough to penetrate it and stick them all together good. So I started drilling the hole mostly just to facilitate more even heat during the welding process. It is also a good idea to put a bevel on each end of these, it makes driving them up into the old tubing easier (especially since there is a bend there very soon going up to the wishbone area, it allows them to go in further) and also makes it where you have a little room to change the angle slightly if you need it to make your rails line up or be level. Again, this is all hand fitting here with die grinder and file.

    Click image for larger version. 

Name:	i-RqGxB6j-X3.jpg 
Views:	109 
Size:	226.5 KB 
ID:	270885Click image for larger version. 

Name:	i-gPk4275-X3.jpg 
Views:	113 
Size:	206.0 KB 
ID:	270886Click image for larger version. 

Name:	i-CSbqWv2-X4.jpg 
Views:	111 
Size:	660.6 KB 
ID:	270887Click image for larger version. 

Name:	i-5NTKk2W-X4.jpg 
Views:	115 
Size:	970.7 KB 
ID:	270888

    You'll also see in this picture here, my "frame rotissere" I built years ago when iwas doing a lot of these. It's basically part of a regular engine stand you'd get from an auto parts store, in a piece of tubing I have bolted to the welding table, with plates and bushings that go in where the steering neck bearings would regularly be. This allows me to keep the frame up at working heigh, held by the steering neck and allows me to turn/roll it into whatever position I want, including upside down to faciliate working on it a lot easier for all the welding and fit up. If I was doing all this on the shop floor or even just sitting on a bench, it would be madness. With the rotissere I can roll my shop chair over to it and sit and work on grinding and fitting things, stand over it, roll it one way or another and it is secured and I can work on it whatever I need to with both hands free. It is very sturdy, I used this same rotissere when i built my Rotax pipe with Dad years ago.

  4. #4
    Billy Golightly's Avatar
    Billy Golightly is offline Always finding new and exciting ways to not give a hoot in hell Catch me if you can
    Join Date
    Sep 2002
    Location
    Live Oak, FL
    --
    15,066
    Blog Entries
    14
    Now comes the most unfun part...just all the back and fourth and contiuous trial and error grinding and filing fitting and checking level on getting these bottom frame rails where they need to be. A couple things I learned over the years;

    Do not weld anything in by itself - cut and fit as much as you can, clamp and hold it all together with bolts, squeeze clamps, etc and then weld it while its all where it belongs. Don't do one frame rail at time. Don't do both frame rails and then the bottom cross bar engine mount...do all 3 at once. Those Irwin squeeze clamps are a God-send. I use those things for so much in the shop and on these kinds of projects.

    The amount of time you spend grinding, filing and making your fit up joints tighter, is a 1-2 ratio of how good your welds will turn out. The less gap you have and the tighter the fit up, the better and easier your welds will be. This is one of those things where the prep and the setup is infinitely more time consuming than actually doing it. But it makes a big difference...

    In the first picutre you'll see the jig I have mentioned, as well as the one side of the swingarm pivot I had to weld in that had been cut out before on this particular frame. It was a trade off of less rust vs having that, so we chose dealing with that.

    Click image for larger version. 

Name:	i-bCCKQt7-X4.jpg 
Views:	111 
Size:	1.20 MB 
ID:	270889Click image for larger version. 

Name:	i-ZMx5k7n-X4.jpg 
Views:	112 
Size:	1.02 MB 
ID:	270890Click image for larger version. 

Name:	i-89DdnLV-X4.jpg 
Views:	114 
Size:	870.8 KB 
ID:	270891Click image for larger version. 

Name:	i-VW33NQz-X4.jpg 
Views:	113 
Size:	936.4 KB 
ID:	270892

  5. #5
    Billy Golightly's Avatar
    Billy Golightly is offline Always finding new and exciting ways to not give a hoot in hell Catch me if you can
    Join Date
    Sep 2002
    Location
    Live Oak, FL
    --
    15,066
    Blog Entries
    14
    Slowly but surely now we're making a little progress and starting to see some real changes and where this is coming together.

    Click image for larger version. 

Name:	i-8KSZWcK-X4.jpg 
Views:	115 
Size:	1.03 MB 
ID:	270894Click image for larger version. 

Name:	i-r82grcQ-X4.jpg 
Views:	115 
Size:	1.19 MB 
ID:	270893

    Click image for larger version. 

Name:	i-wsKq47B-X3.jpg 
Views:	114 
Size:	260.8 KB 
ID:	270895Click image for larger version. 

Name:	i-DtwTdZQ-X3.jpg 
Views:	115 
Size:	244.8 KB 
ID:	270896Click image for larger version. 

Name:	i-BmskPQj-X4.jpg 
Views:	116 
Size:	829.3 KB 
ID:	270897

    One of the things that's interesting about these builds is how the motor mounts on the CR500 engines are offset...they're literally not in the center of the cases, and I guess they may have been originally designed that way for chain alignment in the CR500 frames also. It takes getting use to and does seem goofy when you first set out to do one of these and are looking at everything if you're trying to work off of those. Forget about the mounts. Line up the sprocket, hang it from the head stay, and build everything else around where that falls at.

  6. #6
    Billy Golightly's Avatar
    Billy Golightly is offline Always finding new and exciting ways to not give a hoot in hell Catch me if you can
    Join Date
    Sep 2002
    Location
    Live Oak, FL
    --
    15,066
    Blog Entries
    14
    Will post more pictures and details later this evening probably.

  7. #7
    Join Date
    Oct 2003
    Location
    Las Vegas, NV.
    --
    2,440
    Nice work. It's cool to see the whole process. Thanks for sharing.
    Red Rider's Sand Machine Updated 07/23/14

  8. #8
    Billy Golightly's Avatar
    Billy Golightly is offline Always finding new and exciting ways to not give a hoot in hell Catch me if you can
    Join Date
    Sep 2002
    Location
    Live Oak, FL
    --
    15,066
    Blog Entries
    14
    In these pictures you'll now see the fitting up of the once removed and now replaced - lower suspension linkage mounts. Because the new cross bar is bent, I've found it easier to cut the bracket into two pieces, and then just bend the remainder of the tabs around to fit the contour, and then run a wide weld pass up the middle of it. You of course have to have your jig to bolt the pieces to, to ensure they stay in the right places and location.

    If you're looking closely, you'll also notice I've flipped it upside down. This is because with the addition of the bent cross bar, if you left the bracket the way it was on the 250R frame (flat part, downward, instead of up) then the shock linkage will actually hit on it, because while the mount location itself has not changed, the bracketry and cross bars around it, has changed. You don't want it to slam into the bottom of the tab when the suspension unloads completely at full droop - this was my solution for that situation. Click image for larger version. 

Name:	i-zJQrVQm-X4.jpg 
Views:	112 
Size:	861.5 KB 
ID:	270898Click image for larger version. 

Name:	i-pZK2rtn-X4.jpg 
Views:	109 
Size:	1.01 MB 
ID:	270899


    Okay so the nest thing to do is the front motor mounts. I kind of evolved this over the years also as I made these. I use to try and line and square up to drill through and weld in a boss through the frame like the OEM engine and cradle did for the front motor mount, and I never had much good luck keeping that square and keeping the faces where your bracket would bolt on in line with each other. So I kind of worked the same way I did on other parts of the frame, I made tabs that bolted to the mount with the original bolts, and then made the bracketry to fit in between. On my design, the engine must come out of the kick start side of the frame. As you recall I mentioned that the engine mounts are off set on teh CR500. The left side is really close to the exhaust port, flange, and that side of the cylinder. Making a removable mount on that side is a lot more work and cumbersome than it is worth IMO. So what I do is make that side welded solid, and a mount that unbolts on the right hand side, where you can pull the motor in and out that way. I make saddle gussets that basically doubles up this portion of the frame cradle here because the cr500s are so prone to virbation, Doing a T weld with a bracket on this area without reinforcement might be okay even using the thicker tubing I use, but I still feel like it is a good idea to reinforce it and increase the surface area of the weld holding the bracketry together.
    Click image for larger version. 

Name:	i-bWh3jfN-X3.jpg 
Views:	109 
Size:	167.1 KB 
ID:	270900Click image for larger version. 

Name:	i-Gfz47Sf-X3.jpg 
Views:	107 
Size:	234.6 KB 
ID:	270901Click image for larger version. 

Name:	i-xNXCXT8-X3.jpg 
Views:	107 
Size:	191.6 KB 
ID:	270902Click image for larger version. 

Name:	i-RhgrGR3-X3.jpg 
Views:	107 
Size:	159.8 KB 
ID:	270903Click image for larger version. 

Name:	i-6Z2D2wd-X3.jpg 
Views:	112 
Size:	225.5 KB 
ID:	270904Click image for larger version. 

Name:	i-vDvXscs-X3.jpg 
Views:	108 
Size:	205.7 KB 
ID:	270905Click image for larger version. 

Name:	i-D68j333-X4.jpg 
Views:	109 
Size:	1.13 MB 
ID:	270906

  9. #9
    Billy Golightly's Avatar
    Billy Golightly is offline Always finding new and exciting ways to not give a hoot in hell Catch me if you can
    Join Date
    Sep 2002
    Location
    Live Oak, FL
    --
    15,066
    Blog Entries
    14
    Few more pictures of how I do the front motor mount bracketry. The front mount is all hand made, again, hand ground, filed, etc... Uses two 8mm short bolts to bolt the bracket on and off that connects the motor, to the frame. Saddle gussets are welded length ways and not at the top edges which I read one time was less prone to make them crack than if they were welded 100% all the way around.

    Click image for larger version. 

Name:	i-6DtFPhn-X4.jpg 
Views:	110 
Size:	997.9 KB 
ID:	270907Click image for larger version. 

Name:	i-HjfnpVz-X4.jpg 
Views:	113 
Size:	859.3 KB 
ID:	270908Click image for larger version. 

Name:	i-r6g3fRH-X4.jpg 
Views:	112 
Size:	1.29 MB 
ID:	270909

    And finally, I cut some little corner gussets that go from the footpeg mount areas to go along where the bottom cradle tubing connects, for some additional reinforcement. Probably not necessary, but again, keeping in mind how rusty these frame are in these areas, it's a good practice IMO.

    Click image for larger version. 

Name:	i-bjP8Rk9-X3.jpg 
Views:	111 
Size:	206.1 KB 
ID:	270910Click image for larger version. 

Name:	i-f5hnf3N-X3.jpg 
Views:	116 
Size:	199.3 KB 
ID:	270911Click image for larger version. 

Name:	i-rM57TSM-X3.jpg 
Views:	108 
Size:	197.4 KB 
ID:	270912Click image for larger version. 

Name:	i-HRLwf65-X4.jpg 
Views:	111 
Size:	866.2 KB 
ID:	270913


    And that pretty much complete it minus a little bit of finish welding, making a few dimples for the shift shaft and shifter clearance on the back cross bar thats been installed, etc. The joint at the wishbone will be finish welded in and filled in level, it's just not in this picture.

  10. #10
    Scootertrash's Avatar
    Scootertrash is offline Just Too Addicted: Protecting Our Community The day begins with 3WW
    Join Date
    Apr 2011
    Location
    In the sticks
    --
    4,622
    Awesome post(s).

    This project is waayayay above my pay grade, but I love to see how you pros do it!!!

    Thanks Billy!!
    Quote Originally Posted by fabiodriven View Post
    Trick the people into thinking they're enacting their own will and you have willing slaves.

    Liberalism suspends the intellect of its victims, while at the same time tricking them into believing that they're smarter than everyone else.


    If we've done business together, please leave me feedback. Thank You!:

    http://www.3wheelerworld.com/showthr...t=Scootertrash

  11. #11
    Join Date
    Feb 2010
    Location
    Blossvale NY
    --
    4,567
    Thank you for sharing Billy. ��

    My next and probably last major build on the horizon will be a long these lines
    Trikes:
    '85 ATC 350R
    '85 ATC 250R
    '86 ATC 350X
    '85 ATC 350X
    '84 ATC 200ES Big Red
    '84 ATC 125M
    '85 ATC 110
    '85 ATC 70/110

    If you have bought from me or sold to me, please leave me feedback here>>> http://www.3wheelerworld.com/showthr...+RIDE-RED+250r

  12. #12
    Join Date
    Jul 2010
    Location
    Arkansas
    --
    2,177
    Those who don't do, don't know what it takes. They also tend to complain about price.

    Keep up the good work.
    The story of three wheels and a man...

  13. #13
    Join Date
    Sep 2010
    Location
    NEPA
    --
    7,048
    Beautiful work. I think I have the last one you did? Khaos with ext sub frame
    Please help those who cannot help themselves.

    ALWAYS buying Museum quality machines,3 and 4 wheels. And any and ALL ,NOS parts,EVERY brand.

    I am turning my PM's Off,my Email is billsracing@hotmail.com,put 3WW in the subject. Thanx!

    Gun laws do not stop criminals. BULLETS do.

  14. #14
    Billy Golightly's Avatar
    Billy Golightly is offline Always finding new and exciting ways to not give a hoot in hell Catch me if you can
    Join Date
    Sep 2002
    Location
    Live Oak, FL
    --
    15,066
    Blog Entries
    14
    That would have been one of the early ones, actually. I think that may have been the first one I put the bent suspension linkage cross bar in, if I remember correctly...

    Just searched and found the thread; http://www.3wheelerworld.com/showthr...ighlight=khaos

    that was a nice throw back...even got a picture of my dad in the background I had forgotten about. Thanks for the memory 007

  15. #15
    Join Date
    Apr 2011
    Location
    Mexico
    --
    8,993
    So good to see you on here Billy, I hope it continues my friend
    It sucks to get old

//ArrowChat Integreation Code //