Marty Moates RM 500

[TT]

Maybe I sent it to Ajay instead. It was printed on his page.
No stress. This thread just reminded me about it.

[BAHNZY]

Guy's what am i missing?
What would be the significant advantage of putting a RM500 air cooled engine in a 84 125/250 water cooled chassis over a stock 84 RM500?

[JohnnyO]

The stock RM500 chassis is a 1981 design from the RM465X. The '84 250 is a whole new frame with different geometry, single side airbox and new swingarm and linkage.

[BAHNZY]

John,
Is there such a significant difference?
Most of the good RM500's of the day were fitted with FOX or SIMMONS forks, an 84 250 swing arm with an Ohlins shock.
Would the 84 framed 500 be still better than such a modified bike?

[JohnnyO]

That's hard to say Rod, i think half the reason people did the mod was to make it look like the RN500 works bike of the day.
Goofs '83 RM500 certainly got the job done!

[holeshot buddy]

putting a 500 engine in a 84/250/125 frame
is a great advantage
much better geometry better leverage ratio
big airbox lighter weight
my bike weighs 96 kilograms full of oil with half a tank
tweak the forks fit a shock and you have a much better
handling bike than the old 500
i have owned both and also rm250e
and the hybrid is the best package
you have a rm125e rod imagine it with a 500 donk
cheers rusty

[TT]

Goofs '83 RM500 certainly got the job done!

No! Goof got the job done. 

But don't tell him I said so.......... 

[frostype400]

I bags any rolling rm500 frames motor from the US and you are away again.

[BAHNZY]

I remember at a VIPER meeting a while back there was a RM500 that had a DG single sided airbox, was this to address a specific issue or was it a bit of wank value?

The one thing that i have come to understand with bikes (and it took way to long to work it out   ) is that as the engines gets bigger the more the bike rides you rather than you riding the bike. The advantages that the smaller engines put towards the handling and control very quickly dissipate when the engine gets bigger. There are a chosen few that can reverse this but not many, although there is a lot that think they can.

[JohnnyO]

That's pretty much why the 500 class died in the mid 80's and the 250's became the premier class.
The standard twin sided airbox on those '81-'83 125/250's and '81-'84 500's was pretty restrictive and the big volume single sided aftermarket airboxes were an improvement.

[holeshot buddy]

you are right but a nice rm500 with twin airbox
white power shock ,forks kitted and pipe is a nice bike
its just from my experience with the engine in a 250 or 125 frame
they handle better, mine is a 125 frame and the big engine did change the way it felt
but it still handled heaps better than a rm500 and is a pleasure to ride
those 84/85 frames were derived off the works bikes so this could be why
if they have cd8 up here again and you come up rod you can cut some laps
cheers rusty

[monaro308]

I can't compare anything with something on my PE175 engined RM125E framed bike.Everything is '85 F,but i used the 84 frame because it was in poorer condition to the 85 frame that i have.
It sure is a sweet handling SOB and have been thinking of using the PE250 engine later on.
I absolutely love the way it turns and the way the floater still feels plush under hard throttle.

So Rod....i can hear your mind ticking over now with that RM125F you're working on

[GOOF]

Goofs '83 RM500 certainly got the job done!

No! Goof got the job done. 

But don't tell him I said so.......... 

      Ohhh   thanks  Tony,  ( flattered )

[Marc.com]

The advantages that the smaller engines put towards the handling and control very quickly dissipate when the engine gets bigger. There are a chosen few that can reverse this but not many, although there is a lot that think they can.

And hence the hot new 4 stroke MX bike from KTM is a 350 and there is a pretty good chance the others will follow with something smaller than the 450. Could this be the death of the open class MXer. Will they finally build a 325 and just have one senior class..... will the current generation of  hair gel MXers care too much.

[GT43]

Sorry if this has been posted before.