KTM Rotax Help

[Luffy]

Hi all, looking for info regarding Rotax 504, mine is GS and has counterbalance in it, but as im having to rebuild due to small misshap in desert, I noticed mx dosnt have one and woundering if it would turn in to sex toy or rev quicker and more responsive.
Dont wont to distroy engine with no balance, but looking for a bit more goooo.

PS Dennis hows the Sub going, shame CD gone, us Vic boys had plans for it???

[GMC]

The balance factor may be different in the MX version.
I imagine without the counter balancer it may rev a bit quicker but I did know some guys that had removed them, one from a TT600 and I think the other was a Husky 600.
Both bikes had a strange habit of breaking shock shafts afterwards

[oz555ktm]

    Look Luffy   My xc504 dose not have a balancer rev better then the KTM gs 350 Rotax (Yea that the White sud )

    the big thing is the vib at idle the 350 no vib at all the 504 dont yet the wife ride it she wont get off it ..

    I thing it would be better left in for Vinduro ..

     I am about to remove MX cam and fit a GS cam to Xc 504  I cant use all the Power anway
     

[Luffy]

Have you got a cam as I have 504 gs cam spare

Just ordered new piston and going for 600 now so should have more grunt

Regarding balancer in two minds as all mx bike didn't have it and plenty of other manufactures don't use them, but now as going to a big banger it my be to much and start snapping parts, as Geoff mentioned
May look on thumper talk the atk boys over the pond do lots to the rotax.

Dennis are you going to cookadinia , have new side plates ?

[evo550]

I'm not sure on the rotax's, but I have removed the counter balancer from a xt550 motor once.
You could notice the change at idle (I won't call it vibration, more like a stronger pulse when the engine fired), but once moving around the track, couldn't tell the difference. The bike reved out much quicker, was a good free mod.

[gra1961]

hey luffy,my 504 has never had a balance shaft fitted the vibes arnt anything to complain about.done a fair bit of hours on it and nothing engine wise has broken.cheers gregg

[GMC]

The Rotax motors may have had the option of with or without the balancer but I doubt that the cranks would have been the same. I imagine the cranks of the 2 models would have had a different balance factor.

The 2 bikes I mentioned didn’t break parts due to power, they broke the shock shafts due to vibration and it wasn’t the sort of vibration that made you think it was going to fall apart, it was a high frequency type of vibe.
Both bikes were also used mainly on bitumen so would have spent more time at higher revs.

[oz555ktm]

  you are right 2 cranks  the gs has 2 full crank wheels the xc only 1 on the oil slinger side ..

   and Harf the weight

[Luffy]

So what does that mean then? The mx has lighter crank to rev free or and gs needs the extra weight due to counter balance, will chech with David at floods to find out as he is looking for con rod for me and the part number is same for all rotax,s
Also will talk to Ron wood to get there views as don't want to get it wrong as the parts are scary and trying to have ready for last three events on calendar
Thanks guys.

[Luffy]

Just looked on parts list and 504 and 560 there are two cranks and are fitted to both bikes ? and both have or dont have counter balance now im very F___king confused.

[Lozza]

If you want Rotax parts contact Tony Murphy in the US.

[Luffy]

Can't find tony murphy unless he's a fireman or boxer .?

[jimg1au]

forget the rest these are the go fast rotax 4t guys in the usa
http://www.rotax.net/
ron wood racing

[Luffy]

Yes have been dealing with Elliott and order new piston barrel and other goodies, can't wait like Christmas coming early.

[Lozza]

Can't find tony murphy unless he's a fireman or boxer .?

I just googled "tony Murphy rotas" first 5 results all had the correct details. the beauty of a rotas is all the hard work is done for you. they don't need go fast bits. set them up as per manual and maintain them