CR500 engine transplant to an '85 Honda ATC250R

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Sup guys! This is gonna be kind of a long one  Been working on this project for a buddy of mine. I originally built a CR500/ATC250R conversion for myself about a year ago. Jumped through a bunch of hoops, learned a bunch of stuff as far as how to go about doing it. I'll start off with a quick overview of mine and then get on to some of the pictures of my friend's that I'm working on now.This is my 85 in my "Chassis Rotisserie" I made that bolts onto the end of my work table. It rotates around 360 degrees and is stout enough to hold a complete machine engine, gas tank and as you can see entire rearend too from the steering neck. Makes it very hand for forming and fitting up parts, and getting into difficult areas to weld Here it is upside down in the stand with the bottom engine cradle rails lobbed off to make room for the more depth the CR500 motor has. The next biggest problem, was this cross tube running that joined the 2 sides of the frame together, that the shock linkage also mounted to. The distance between the CR500 motor's bottom and where the rear motor mount is, is deeper and thicker then the previous ATC250R motor. On my build, I notched this out, severely, and welded in a piece of angle iron to give me the necessary clearance.It worked, but it wasn't real pretty. AND, it wasn't as professional of a job as I felt like it COULD be. I had (and still do, to a certain point) have some questions on the rigidity of this, but my machine was built to do flat track racing only, so theres no jumps or real bumps to ever speak of that would work the shock linkage much. After this, everything was pretty straight forward. And with A little bit more work I ended up with this:And then shortly thereafter, my finished product!I've got a lot more up close and better pictures detailing all the fabwork of this build I'll be happy to show if anyone is interested in the bottom frame rails, motor mounts, etc. But this is mainly just to lead into my buddy's build and what I'm doing with it.
Reply:Heres my friend "Syko" that I'm doing the build for posing with his nice cherry painted frame we're going to start chopping up shortlySyko being, well, SYKO  Note, I do not condone these type of safety practices or perhaps the lack thereof  You can also see my 500R stood up on the grab bar in the backgroun over his shoulder.So heres his frame now with the engine cradle hack-sawed out. I do a lot of manual work with hack saws and hand files, not because I'm getting paid by the hour (cause I dang sure aint ) but because I like the results it gives better 99% of the time.Now we started notching out the rear section of his linkage tube like I did on mine to weld in the angle iron to make room. And the more I looked at it, the more I thought to myself "Man, I can do this a better way!" And the bent piece of tube you see right there was the beginning of it (more in next post)
Reply:Soooooooo.....I lobbed out that entire tube of the frame, with the shock linkage mount and everything. And I began hand fitting that bent piece of tube ( 1.250x083) into place. If you look closely you'll notice that I used some bits of aluminum angle bolted to the bottom of the swinger and then clamped the linkage to it via some vicegrips to preserve its location and angle so that there would not be any geometry changes with the new cross tube and mounting tabs. Everything would fit back into exactly the same place, and I would build around the location of that link.And heres what I ended up with today. Came out looking REALLY good I think. I switched down to a 1/16th Tungsten from the 3/32 I normally run and I'm MUCH happier with the results of the weld since then.Last edited by BillyGoat; 01-18-2009 at 11:39 PM.
Reply:The high frequency start on my Miller Dialarc HF I'm using to weld all of this with has been giving me a little bit of trouble on not wanting to switch off and go over to DC after the arc has been started, but once it does flop over boy it sure goes nice. Thats pretty much where we are right now. Next I'll be doing some aesthetic modifications to the subframe, and work on getting the bottom frame cradle rails bent up and tested fitted into location a long with the bottom motor mount. Any questions or comments, post away.
Reply:When we have to make a splice joint in pipe. What we do is weld in a piece of smaller pipe into one side of the joint. Then slide the larger pipe over the stub and weld it all together. We have had much luck with the added strength it supplies. Looks good though. And I like the sparks in the mouth post too. Ha-ha.        Sincerely,             William McCormick
Reply:Seems great!I´d guess I shoulnd´t be telling you about how unstable tricycles are when you have a 500cc 2 cycle engine below it 8SMy Babies: HF Drill pressHF Pipe Bender3   4.5" Black and Decker angle grindersLincoln Electric PROMIG 175that´s it!
Reply:BillyGoat,Wow that is a great project. The first set of pictures show flat track tires . Is it to be raced? I would like to see some video on the finished product. Keep up the great work.
Reply:Thanks for the replies guys! Yes, I do actually ride this thing pretty often and haven't killed myself yet. I raced it a few times before I ran into some financial difficulties...haven't been able to really get back to the track with it since then. I did have the pleasure of taking it to a 1/2 mile stock car track down in Ocala back in May of last year to get mine broke in. I'm a good rider but it was even spooky to me to have it break loose in the corners at 65-70mph. Heres a video of my riding my 500 with the helmet camera around when I first finished mine:
Reply:That is awesome!!!!!
Reply:WOW! Thats some good footage. Thanks for posting.
Reply:Got some updates on this, had forgot to updates my thread here with my progress Heres a couple of pictures after I had bent up the tubing for the engine cradle (JD2 model 3 bender, tube is .083 wall 4130 1 1/8OD) Pretty much ready to set the motor back in it and get everything setup for the 2 final motor mounts.Some more with the motor back in it, and getting the bottom motor mount tabs welded in. The tabs are pre-fabbed, and come from A&A Manufacturing. Huge time saver in my shop, and they are reasonably priced.
Reply:These are the threaded bushings that will be welded into the frame for one of the front motor mounts to bolt into. You'll notice the one isn't exactly in the center of the frame...it does look weird, and I wish it was. The problem I was facing though was with the way the bend was in the frame, that one had to be in that position for the motor mount plate to stay somewhat in the same plane as the other. You'd think it would work just the opposite, but it doesnt.Heres the ones that are sunken inside teh frame rail, welded permanently into place now. You can look across the exhaust flange to the other rail and see where the othersides pieces are going in. Those will actually be welded onto the exterior of the frame, pointed inside. Its odd how the motor mounts are casted on these CR500 engines, everything is offset.So heres just a couple pictures of the bottom cross rail and mounting tabs, plus the front mounts now that the motor is out of the way. I'm getting ready to go around and weld everything into place all the way around.Overview of the whole frame after I just finished welding it. Some closeups coming up next.Just another angle of pretty much the same thing. Just finished welding everything inHeres about the best overall closeup view I could get of the cross member TIGed in, and the bottom motor mount tabs as well. The look like their up pretty high, but thats about the only way it can be and still get the bolt in and out without a bunch of crap. Got some pretty nice consitent beads, and you can see the penetration through the backside of the tabs that shows it was fusing together well.
Reply:Showin off my weld beads... I'm no ztfab though hahha Next up will be a preview of the new subframe style the frame will sport.And there they are. This was SYKOs idea, mostly for aesthetic purposes. He had already lengthened the sub frame how he liked it for his size, and he mentioned trying to do this for a little bit of an alternative look and style thats not really seen elsewhere. Routing the exhaust and muffler around it might end up being slightly challenging. I'm a little bit concerned about the rigidity of the subframe in this configuration, mostly from twisting...but I'll do with it what I can.
Reply:Nice fab work.Miller Dynasty 200DX Tig Welder
Reply:Quite a project. Looks good. Just don't let that thing run up on your foot and rip your leg off.
Reply:Your health insurance is paid up, and you employer doesn't mind you being off work for 9 months?
Reply:Just about got this thing finished up...Me doing some welding on the exhaust Me trying to make the arc jump a gap for the camera to catch, hahahaJust about there...not to much more left to do. Borrowed the rear fenders and seat off mine for the pictures. I think it looks pretty dang good.
Reply:hey man this thing is awsome!! would you consider doing this for other peple?
Reply:You boys must be welding legends.  That SYKO is on the wrong PATH. I would  follow him but I think I would be leading. Ive nearly been killed on 3 wheels a couple times. The last time, while rolling down an off camber hill, the three wheeler landed on my back. The first time at 14 years old no helmet I was pinned up side down with the flat track bars across my neck  pinning me down. Had they been motocross bars, I wouldnt be here.BTW, I dont have pics of my first 3 wheelr but it was made from a Suzuki 2 wheelr with a rear swing arm swap. Swapped one rear wheel for two. Had a ski for the front otherwise I ran a standard 21 inch wheel up front. Come to think of it, the ski attached to the front tire.  I like the 21 inch front better than the stock fatties three wheelers come with. Today I only use 3 wheels for the sand or snow. Otherwise Im a KTM driver. Gotta love the upside down forks.
Reply:I know this thread is really old but damn, that thing is freaking bad-***!Brad GeorgeCurrent Equipment:AIRCO Heliwelder IV 300Amp Model - Total Awesomeness!Old 120v Hobart Handler MIGVarious grinders, cutting tools, hammers, clamps, ect..."I'm an amateur welder with lots left to learn..."
Reply:Hahahha...looks like fun.  I had a 1990 CR500 for a few years, traded it for a Hardinge lathe.-AaronJet 17.5" Drill Press1942 South Bend 16x84 Lathe1980s Miller 320A / BP --- 2013 Power Mig 2562012 Jet 7x12 Horizontal BandsawVictor O/A Setup
Reply:Very cool project.Any updates or vids of it in action?