BannedCR500Riders.com

Has anyone done the air cooled AF conversion, I know the obvious problem as the sprocket being on the wong side!!!

I have a rolling frame and a 81 air cooled motor??

Busy at the moment doing a 2004 and a 1995 engine!!

You mean a 480?

Depends how big I can bore it!!!! Yes a 480!!!

Depends how big I can bore it!!!! Yes a 480!!!

Flip the swingarm, and run with no linkage, Ala' KTM

I think it would be sweet!

Looked at the swinging arm and other things like the wheel and rear brake looks do-able. Just wondered if anyone had do it with pictues??

I parked my 84 next to my 03 125 studied the idea up for a while and concluded it wasn't worth the effort. The cooling fins made it almost impossible and would need to be modified to the point I felt it would compromise cooling, not to mention it would be just plain ugly when done.

.02

I think it would be neat. All I gotta say is if anybody builds one, hows about coming down to Florida so I can ride it

Florida is a bit far for me to drop down???

Looks like a plan to me!!!![/url]

I can't wait to see how it comes out!

Isn't that a 450? The first 480 was in '82 and it was black. I "think" you have an '01 450 engine there.

Regardless, awesome idea!

Thats right mate it is a 1981 CR450 which is acutally a 431cc, it is almost a bare engine at the moment just used to test the size etc, the cases and mounting points are the same, I do have a 480 but its complete at the moment in the bike and running, thought it best to test fit first.

I think it would be sweet to run a finned bike like this because it should have a much lower COG. How much difference it would make I don't know...but I'd like to find out. I think a CR500AF with no radiators or coolant would be an awsome handling machine

Totally bad ass idea I think as long as the engine is strong and usable.

Neilios wrote:Thats right mate it is a 1981 CR450

Right on a CR450 engine in a CRF450 frame!!!!

There are better things to do with that engine. Stick it in a 1980 CR250R frame with the 1981 swing arm and make a 1978 Honda RC400 works replica....

redrocket190 wrote:There are better things to do with that engine. Stick it in a 1980 CR250R frame with the 1981 swing arm and make a 1978 Honda RC400 works replica....

I gotta agree with the above.

The engine will not be modified therefore can be fitted in any frame in the future. I have a spare CRF but not a 1980 Cr unless it will fit my 80!!!!!!!!!!

OK if you think you can put a standard air cooled engine in an AF frame without modifying the engine to fit, you are in denial.
Also that goes for modifying the bike to fit the engine without detracting from the reason why you are using the later model bike in the first place.
It has nothing to do with the fins either or the exhaust.
The 84 CR500 engine is hard enough, but the 81-83 is almost impossible.
I am not saying it can't be done, but it would require a lot more than you realise, both money and time also machining.
Of all the talk about doing this conversion not one person has mentioned the unique problem / challenge that is faced with an air cooled AF conversion.
It was the same sort of challenge as making an air cooled 88 CR500.

This is not being done for any other reason than to get people thinking about this so if anyone trys this they are not going in BLIND.
At least you will have a head start and not so much to work out.

CR500R7 wrote: Of all the talk about doing this conversion not one person has mentioned the unique problem / challenge that is faced with an air cooled AF conversion.
It was the same sort of challenge as making an air cooled 88 CR500.

And what challenge is that?

It would be easier to do with the '84 engine. The bike would be lighter, have a lower COG, tractor like torque down low and hit hard.

Biggest challenge I can think of is the pipe. The low pipe wont clear the fins w/o modification and then I wonder if it would stick out far enough to be cumbersome.
At least you wont have to bore the cases for the swing arm pivot bolt.

I knew someone would bite pretty quick.
Now this is not going to be a slow old fart EGO TRIP.
The challenge.
OK fair enough the front engine mount is not as far forward, and like you said you don't have to bore the cases.
The problem is, take a look at the rear engine mount on an 85 -01 CR500 and then look at an 84 CR500.
The 84 has 2 rear mounts and that top one is going to clash with the shock worse than any 85-01 rear mount, some are clearancing them as it is.
The way around this is to mount the jug on an 85-01 cases, which creates a new problem the fins contact the water outlets.
Problem solved machine the water pump off and weld up the case to look like a longer 84 case.
85/86 with the shorter case height would give more clearance up top.
With the later cases you are back to extending the cradle again.
Useing the later cases means you don't have to cast new ones to avoid the shock issues
You could cut the top mount off but that would mean destroying perfectly good cases, plus it would not be the best way to support the rear of the engine.
Also useing the later cases allows you to use the later water pump cover / clutch cover to access the clutch without taking the whole side off.
Bob sort of had the idea when he said turn the swingarm upsidedown but that creates another problem, airbox /shock interferance with no linkage means sorting out a suspension problem.
So no matter which way you look at it the rear mount poses a unique challenge for sure.
Now after reading this you should understand why I said time, money and machining and not impossible.
This is all before you even get to worry about the fins or the exhaust.
The reason for the later cases is to keep the rest of the bike as stock as possible so the suspension works as it was supposed to.
The reason why we go to the AF frame is for improved everything, SO WHY F@#K IT UP with modifying the suspension.

Well this seems easy enough for the rear mounts since they dont actual go into the case. The H shaped piece that bolts to the engine and swingarm pivot would be easy enough to modify