RM500 DG pipe powerband

[Momus]

I bought this RM500 fitted with a DG chamber and muffler from a bloke who flat tracked it. It came with a second exhaust which I didn't look closely at but assumed was the stock setup.

The stockie turned out to be another DG. I haven't ridden the bike yet and would like to get an idea from any 465/500 RM owners of the change this fairly fat bellied pipe will make.

I'm a bit concerned that the relatively tractor like curve I remember from one I owned 28 years ago will have been upset and given it came with a sock the jetting could be wrong for the airbox I am refitting. Any comments appreciated.

Marcus

http://i1378.photobucket.com/albums/ah84/msfracingcomponentsmus/003_zpsbcf45159.jpg?t=1410866332
http://i1378.photobucket.com/albums/ah84/msfracingcomponentsmus/004_zpse5680a7b.jpg


 

[SON]

Somehow you have answered your own question,
28 years ago you wanted that RM to rev harder
Now around 50 you want it to be smooth
Maybe a little more flywheel weight

[Momus]

Thanks SON.


Closer to 60.. 28 years ago it  had enough of everything.

I am thinking about flywheel weighting. I have a feeling that the crank wheels on the RM are already relatively high inertia

At the moment I am interested in any feedback on the change in delivery the DG chamber makes.

I've heard they are regarded as a desert racing pipe in the US.

[SON]

Then I suggest a more modern external rotor ignition system and slightly lower compression
It will be far easier to kick start and a much smoother Powerband

[Momus]

SON I've got the head in the mill at the moment  putting a decomp valve in it....

Interested to know if you can recommend from experience a suitable outer rotor CDI?

Marcus

[SON]

No need to machine the head,
Suzuki had a thick head gasket
I think we used a 1996 RM 250 Ignition

[Momus]

SON, thanks for that.


Did the RM250 CDI look like this one?
http://s1378.photobucket.com/user/msfracingcomponentsmus/media/SuzukiRM250stator_zps6cdca38b.jpg.html

[SON]

Yes similar but it was years ago that I last saw ir

[ELC hunter]

My 500E from new had 3 head gaskets on it. Removed 1 and It would kill a plug every couple 100 klm.

[MaxPower]

Thanks SON.


Closer to 60.. 28 years ago it  had enough of everything.

I am thinking about flywheel weighting. I have a feeling that the crank wheels on the RM are already relatively high inertia

At the moment I am interested in any feedback on the change in delivery the DG chamber makes.

I've heard they are regarded as a desert racing pipe in the US.

They are more known for a cheap (inexpensive and quality) exhaust that you can replace your stock pipe with when you smash it

[MaxPower]

Then I suggest a more modern external rotor ignition system and slightly lower compression
It will be far easier to kick start and a much smoother Powerband

Isn't it an issue when fitting a modern ignition to an older machine that there isn't enough room?
My KX can't fit a kx85 stator because the pick up that sits outside the flywheel sticks out too far

[Momus]

I scored a sound standard pipe with a squashed header from one of the RM experts here last night.

I've repaired the damage today with air pressure and heat and should be able to answer my own question about the difference between the Suzuki and DG expansion chambers.

Next question. SON mentioned a 550cc RM, presumably big bore, in one of the threads. Is there readily available  info on this?

I assume special piston, special sleeve and some concern about the strength of the cylinder.

Cheers.

[D project]

Air pressure and heat eh, I knew I shouldn't have sold it