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View Full Version : New start to the 500 project



jeffatc250r
01-11-2007, 05:01 PM
With the advise from several members i aborted the way i was going about installing a cr 500 in an 86 r. Hopefully now im on the right track. Let me know if everything looks ok

Jason Hall
01-11-2007, 05:28 PM
Thats the way to make that baby fit. If you get the right size tubeing you can slide It Inside the stock frame In the front. How did you notch the rear lower frame.

yamaha_tri_z
01-11-2007, 05:57 PM
That lokks good. keep going on that. I would get some square tube for the frame and get it fit under that big 500 motor. you will thank me for this advise someday. there will be less chance of hitting a rock and cracking the caseing. good luck on it and i will check in and see if you get any farther.

4cylinders
01-11-2007, 07:05 PM
hey, you can build a bolt in subframe, bolted to the front mounts and the footpeg bolts. would make it real easy to duplicate, or replace/reengineer if needed.

200x Basket
01-11-2007, 08:21 PM
much better!!!

3leggeddog
01-11-2007, 08:24 PM
looks great.can you see how well everything lines up now?your exhaust will fit better,you can change the plug without moving the tank,you can fit the carb onto a stock airbox of you want!looks sweet man.

super90
01-11-2007, 08:26 PM
I never knew there was that much involved in making a 500r. I would just stick to the tecate frame and kx 500 engine, but thats because I suck at welding. But the subframe idea would be nice.

jeffatc250r
01-12-2007, 05:34 PM
I think ill use jasons advise and use round tubing that will fit the original frame. Im gonna head up to my friend-steel supplier and see what hes got prob tomm. As far as the rear cross frame piece i sliced it on the top and also on the front side towards the bottom, i was thinking of just welding in a piece of angle iron on the inside for extra support, is that what you did jason?? Also what are you guys running for sprockets? Im guessing it would be different or is it?

jeffatc250r
01-12-2007, 05:40 PM
Another question is i have a 39mm keihin to throw on this, it actually came with the bike but i never rode it since the motor was seized up due to a cooked crank. That baby was pretty bent. I installed a new crank, crank bearings, piston (70 over) and a few other small things. My question is this, is this carb big enough? I had it on my 250 and it actually ran great.

Jason Hall
01-12-2007, 07:39 PM
Yes I welded a piece of angle In the lower rear tube. Let me know If you have a hard time finding the tubeing & getting It bent. I might be able to get more of the same stuff I used on 3leggeddog's.

cr480r
01-13-2007, 09:41 PM
I was curious of what is used to make the lower mounts? I am about to start a project involving a custom lower engine cradle, and was unsure of how to attach the bottom engine mounts to the frame. Any ideas or pictures? I dont want to do it twice.

Jason Hall
01-13-2007, 10:11 PM
Get your engine held In where you want It with the top & rear mounts. Then weld In a piece of tubeing In line with the bottom mounting holes & build little rounded ears off the cross tube, then bolt er up. When I do It I make the tabs & drill the holes, then bolt the tabs to the engine tighten them up & weld them to the tubeing.

cr480r
01-13-2007, 10:58 PM
Get your engine held In where you want It with the top & rear mounts. Then weld In a piece of tubeing In line with the bottom mounting holes & build little rounded ears off the cross tube, then bolt er up. When I do It I make the tabs & drill the holes, then bolt the tabs to the engine tighten them up & weld them to the tubeing.

Thanks. That makes perfect sense. I love it.

4cylinders
01-13-2007, 11:26 PM
hey, check out this picture, great idea.

SpudLee
01-18-2007, 02:09 PM
Does anybody on the forum have an ATCR500R built using a CR500R frame with ATC250R components?

Or does everybody only build an ATC250R based chasiss mod'd to fit a 500R?

I have the option, I would like to go with the CR500R frame. This way I still have the option of putting an ATC250R back together in the future. I would rather tear up the dirtbike frame.

What are the "con's" of using a CR500R frame? What is the best way to combat these "con's"?

Thanks

3leggeddog
01-18-2007, 09:25 PM
the cons are it's tall,and you gotta fab up tripples.we used a 350x set of tripple,with 250r forks.you press the cr stem out,and press it in the 350x tripples.i belive the tripple are still here if you are interested in buyin them.also you have to fab up a rear subframe,and fenders/seat setup.next you must fab up a swinger/rear end.

Louis Mielke
01-19-2007, 12:22 AM
Its alot of work and honestly you'd probably be happier with the 250r conversion....some of us just can't be happy doing things the logical way.:rolleyes: :rolleyes: :rolleyes:

Thats alright though, I'll get mine the way I like it....eventually lol

200x Basket
01-19-2007, 11:38 AM
A 250R frame can be had for under $100 so you can rebuild the 250r anytime you want. you will have much more then $100 in fab work converting a cr500 into a atc. either way you will have a bad ass 500r so get to work!!!

jeffatc250r
02-07-2007, 04:44 PM
I know its been a cpl weeks but i finally made some progress the other day and finished the frame. Basically i used jason halls idea that he used to make 3leggeddogs frame with a couple little revisions. I didnt like the look of the hacked up rear cross tube, so i welded a strap from the frame to the bottom shock linkage mount to keep it in its original spot, then cut it from the cross tube and then cut the cross tube right out and then welded in a new one an inch or so back, it works perfectly! There is over a quarter inch clearance to the back of the motor. And there is still plenty of room for the linkage to do its thing. I am hoping by this weekend i will have it up and running, providing nothing bad happens. After a few test runs and i know everything will work i plan on tearing it down for powdercoat. Also how did u guys route your water hoses? There is an extra port on the head that the 250 didnt have, a 2 into 1 deal??

Mike_Ham_250R
02-07-2007, 05:12 PM
Is that a 450r swinger?

200x Basket
02-07-2007, 05:20 PM
i just capped off one of the top ports. looks good

3leggeddog
02-07-2007, 08:45 PM
that looks alot better.i think you'll find it a much easier swap now.nice work.


i use a carb vaccum plug with a hose clamp to block off the right side port.everything else should bolt right up.

firefirefire90
02-07-2007, 09:03 PM
why would you want to block off the port?

jeffatc250r
02-07-2007, 10:16 PM
Yeah i guess it dont really need two ports on the head. What r u guys running for sprockets?? And yes that is a 450 swinger that im only temporarilly using until my +8 comes back from the powder shop. I think one of u guys used a 89 yz kick right? Will that work with no mods?? Im having a hard time finding one.

Mike_Ham_250R
02-07-2007, 10:26 PM
Yeah i guess it dont really need two ports on the head. What r u guys running for sprockets?? And yes that is a 450 swinger that im only temporarilly using until my +8 comes back from the powder shop. I think one of u guys used a 89 yz kick right? Will that work with no mods?? Im having a hard time finding one.
Aww man, I thought you were gonna use the 450r swinger. I have yet to see a 500r without a huge ass swinger.

Louis Mielke
02-07-2007, 11:20 PM
Does anybody on the forum have an ATCR500R built using a CR500R frame with ATC250R components?

Or does everybody only build an ATC250R based chasiss mod'd to fit a 500R?

I have the option, I would like to go with the CR500R frame. This way I still have the option of putting an ATC250R back together in the future. I would rather tear up the dirtbike frame.

What are the "con's" of using a CR500R frame? What is the best way to combat these "con's"?

Thanks


Here's a mine. Its a CR frame conversion. THis picture really show how much taller it is than the stock 250. Right now its torn down for a rebuild, lowering it as much as I can and cosmetic upgrades and stuff. The 250r mod is honestly much easier in the long run and arguably a better conversion but I'll have the kinks worked out of mine with enough time.

a few weeks after the first build
http://i106.photobucket.com/albums/m254/louis_mielke/smallbikes.jpg

most current progress pic.
http://i106.photobucket.com/albums/m254/louis_mielke/100_0105.jpg

cr480r
02-08-2007, 05:44 AM
How do you start that thing with that little kicker?

Mike_Ham_250R
02-08-2007, 07:16 AM
How do you start that thing with that little kicker?
I think he has that accu-start *Edited**Edited**Edited**Edited*.

Louis Mielke
02-08-2007, 08:06 AM
I have the accustart decompress. Makes it a lot easier...although...I have started it with out the decompress. Its doable just a lot harder. I mainly got the decompress to prevent the kicker from breaking or the cases.

3leggeddog
02-08-2007, 04:45 PM
hey jeff.i messed up when i built my kicker,if i woulda slowed down,i could had a sweet one.what i ended up with is a 96 cr250 kicker,ground down to slide in and lock under the pipe.this works very well,but i had to dimple the frame for the kicker to clear.now you can make a spacer to bump the kicker rout on the kicker shaft,but with so much compression,i don't like that idea.you will be putting alot more stress on the kicker,aswell as the shaft.

my first kicker was a yz426/450.the problem i had waas that the circumfrence of the 500 lower pivot knuckle was larger then the inside dim of the yz kicker.so i ran it in the mill at work,and sized it acoordingly.well then the part of the kicker that rest against the knuckle waas so thin it broke.so i bought the cr250 kicker.

now heres where i coulda kicked my self in the ass.if you buy a yz426/450 kicker,and a 96cr250 lower pivot knuckle,they will slide right together,and slide right on the kicker shaft of the 500.the yz kicker will then clear the frame,and fit very nice.i wish i would not of driled out the yz kicker now,but i did not know all this till i got comparing the pile of kicker parts i had,trin to make something work.

the very first kicker i made louis has now.it is a cr250 lower pivot knuckle,with a blaster kicker milled to fit.you can go that route also

200x Basket
02-08-2007, 04:51 PM
my kicker works great. the key is to have a well tuned easy starting engine. you do not want one that you have jump on to start. i extended my kicker by about 1/4" and then rebent the kicker to my liking. no dimpled frame. also the reversed brake pedal makes a BIG difference in starting.

atc300r
10-22-2019, 01:08 PM
Good info for building a 500r.