'86 ATC 500 conversion...parts

[Maico 500]

Guys...is there anyone still out there making ATC 500 conversion pipes ?? Back in the day when I did my swaps,I had to modify a CR 500 pipe. After I got out of the sport,seems as though I saw an ad or 2 from hot rod shops that were building ATC 500 conversion pipes. Allen Knowls at CT Racing maybe ??

[200x Basket]

i did not find one. the cr500 fmf pipe i used was a easy fit. the stinger was wrong and i had to cut and twist it at two welded seems. it only took about an hour to make and at $400 plus for a custom job it was way cheaper.

[tony_250r]

Who needs a 500 when you can bolt in a 400R stroker motor like FTZ’s, if you have the cash;
http://www.ftzracing.com/ATVpg.html
http://www.ftzracing.com/images/Monster.jpg

Or the Trinity ProX power plant:
http://www.trinityracingproducts.com/lib/trinityracingstore/250pmt

http://www.trinityracingproducts.com/promxtt2.html

Nice set-up 200xBasket

[Maico 500]

With the same amount of $$$ put into a CR 500 motor,those little 250/400 wanna be motors won't stand a chance. As the old saying goes..."There's no replacement for LARGE displacement !!" You want something that REALLY moves??....put a punched and stroked KTM 550 motor in an ATC chassis and see what happens....:). Your eyeballs WILL get pushed to the back of your skull.

[tony_250r]

Yeah, I know there is no replacement for displacement. But you will have to weld the cases togather to handle that much power anyway, lots of reinforcement involved. If I wanted that much power I would go with a 400R alky motor.

[Maico 500]

Weld the cases together ?? Reinforcement ?? I've never had any twisting or cracking problems with the swaps I've done yet I don't moto X these either. Just some fast,5th gear trail and fire road raging out here in MI. Back roads are a blast. Half the fun is doing the swap.

[tony_250r]

I'm talking about using the 250R bottom end, not installing a 500R motor. FTZ uses the stock 250R bottom end with some mods.

Don't you have to pinch the ATC frame to make a 500R motor work?
And are you saying that you can put a 500cc cylinder on the 250R botton end?

Thanks

[ATC crazy]

500R on a 250R bottom end????? Can you say "tweeked crank." ;)

[Maico 500]

Tony_250R...Without looking at FTZ's mods,I can tell you that they are using the 250 cylinder that has been modified for a big bore cylinder and probably a stroker crank. Those mods have been around for a while now. Allen Knowles at CT Racing was 1 of the first guys to do it. A 500CR cylinder won't fit on a 250 lower end. Even if it did,the stroke would be too short to make up 500cc. The CR 500 motor fits nearly the same as the 250...spacers need to be made to fit the rear case where the swingarm shaft runs thru the cases. This is where the first mods should take place as you have to line up the sprokets and chain FIRST and then work your way around to the front.

[200x Basket]

there is a company that puts a cr500 top on a 250r bottom. i cant think of the name but it looks like trailprotrailprotrailprotrailpro

[tony_250r]

Yeah they have a longer stroke, and FTZ uses their own cast jugs, CT cast their own jugs too. I've seen supper very fast FTZ and CT stroker motors at Whitewater CA in Palm Springs and at Glamis CA.

A stock 500R motor would need a lot of mods to compete with a FTZ alky motor or a CT ProX 310 mod.

To make the stroke longer, all one has to do is use a spacer plate and longer connecting rod.

Thanks for you toughts.

[tony_250r]

200XBasket, is you frame pinched, it looks like it is?

[Maico 500]

What are the CT and FZR motors rated at for HP ?? A mild port job to a CR 500 will easily put it over 110 HP. Almost double that if you run it on Alky. A longer rod does not make a longer stroke. The distance from the crank center line to the crank pin is what determines stroke.

[tony_250r]

I must be confuse, I thought that you measuered form the crankshaft to the connecting rod piston pin. Another way of makeing a stroker motor is using a different piston, the connecting rod pin will be in a higher for a longer stroke. I think you would have to run 3 stage porting and and raise the compression and use race fuel to get that 110 HP. But those are the mods I meant. If you do that, you would be in front of the pack.

[Maico 500]

You can measure stoke by total distance the piston travels also. The farther the crank pin is located from the crank center line,the longer the stroke. The closer the crank pin to the crank center line,the shorter the stroke. The rod only dictates the crank center line/pin distance. The pin location on a piston can be anywhere...the piston will only travel the distance from the crank center line to the crank pin X 2.

[tony_250r]

Yeah I agree.

[JohnR.]

Just a quick comment. FTZ did the porting on my first jug and also on the one ChrisD is running right now so I know something about the place. Unless they changed it the way they make it, a 400R is a stroker crank but with a Honda Pilot top end. I am not a big fan of the 500R conversions, I did one about ten years ago and a friend of mine did one about 5 years back, it just vibrates the trailprotrailprotrailprotrailprotrailpro outta the poor frame. Anybody who thinks these Pro-X kits are not a formidable foe for a 500 may be surprised when one whoops up on them. I know the potential for making power with a 500cc is greater but even with a giant piston and the stock stroke (330cc) the vibration is still nothing compared to a 500.

John

[Maico 500]

After growing up and riding nothing but big bore Maicos,a '73 Suzuki TM 400,a '78 Suzuki RM 400,a Suzuki LT 500 and several '85-'89 CR 500's....A little "Buzz" in the finger tips is nothin'!! I'm not knockin' FTZ,CT,Trinity or any one of those guys building hot stockers...they DO run hard!! I'm just used to that low down grunt, Big Block Chevy style, "bring it up from the basement and hammer it hard with the loud handle", big bore powerband!! A bored,stroked,piped,ported and BALANCED (key word there) 500 is a rush that never quite goes away.

[Curtis-Tecate3]

C'Mon Maico-Breako....
"A mild port job on a CR500 will get you 110 HP, double that on Alky" You may fool some inexperienced folks here but not me. You might punch 110 all out and on Methanol but if you think you are getting anywhere near 200 HP on a 500 single you are wrong.... Sorry.

Curtis.

[JohnR.]

Curtis, I am glad somone commented on it because I wasn't gonna touch the 110hp claim with a 10 foot pole!! 200hp??? LOL!!!

John

[CartmanKXT250]

Those FTZ 400R monster motors arent all they've cracked up to be....the cases are EXTREMELY modified..it's easier and cheaper to just get a CR500 engine and transplant...to 200x_basket, Mac Racing puts a CR500 top end on a 250R and it does NOT look like trailprotrailprotrailprotrailpro....your idea of a good CR500 transplant and mine dont see eye to eye either..Your ATC was pretty tweaked but we wont get into that......... Mac Racing does very quality work. The Hybrid is achieved by using a +7 stroker crank and extreme bottom end modifications..In my opinion if your looking at going to a big bore, I'd suggest a Polanda done by MP Racing...If it blows up, you can put your OEM R cylinder back on and go riding because its at stock stroke and there is no bottom end modification required...Dave just uses a stronger rod to push the huge piston...But then again, ESR is doing a 330cc bolt-on cylinder..for the silent but deadly applications! Just lie to your buddies and say its a Pro-X 295....and smoke em :)

[Maico 500]

First of all,BOYZ...the '85 CR 500 motor was rated at 95 HP stock. A mild port job WILL get it to 110 without a problem. I know,I've done it AND run it on a rear wheel dyno. Second..I said "ALMOST" double the HP. More like 175 HP. DYNO'ed. You really should have known !! LOL!!

[Billy Golightly]

First of all,BOYZ...the '85 CR 500 motor was rated at 95 HP stock. A mild port job WILL get it to 110 without a problem. I know,I've done it AND run it on a rear wheel dyno. Second..I said "ALMOST" double the HP. More like 175 HP. DYNO'ed. You really should have known !! LOL!!


Sorry, I really gotta disagree with the 95hp stock...Got any documentation to prove this? Every thing I've ever seen or heard of the early 500 motors was in the high 40's range.

[200x Basket]

look here. most agree the 85 made the most HP at around 50hp

http://sidecase2.tripod.com/larrycr500.htm

[JohnR.]

After this I am going to refrain from getting further involved in this lunacy, NO stock CR500 ever made 95 horsepower, I'm sorry but it didn't. Now if you'll excuse me I am gonna polish my 300hp stock '86 GSXR 750. Hehehehe!!

Later.

John

[Maico 500]

Buff it 'till it shines,John.

[CartmanKXT250]

Got any CR500 engines laying around buddy? I'm in Michigan and lookin for one :)
I see your in Flint..I'm from Traverse City

[ATC crazy]

I was gunna say...95 HP stock :shock: I think they're in the low 50 range. Still...its a lot of POWER! :twisted: