OzVMX Forum

Clubroom => Tech Talk => Topic started by: PRITCH39 on October 18, 2010, 09:53:57 pm

Title: RM250A NEED MORE BOTTOM END
Post by: PRITCH39 on October 18, 2010, 09:53:57 pm

Hi all,

I have an RM250A, I was wondering if any one knows if there are other model/heavier fly wheels that will go on this to help with the lack of bottom end pull. The motor is fresh and jetted well. any suggestions appreciated.


Brian 

Title: Re: RM250A NEED MORE BOTTOM END
Post by: Lozza on October 18, 2010, 10:05:24 pm

more compression
better pipe

Title: Re: RM250A NEED MORE BOTTOM END
Post by: TM BILL on October 19, 2010, 05:44:18 am

Put a B motor in it  :)

Title: Re: RM250A NEED MORE BOTTOM END
Post by: Ktm181 on October 19, 2010, 08:38:33 am

Add 1 inch to header pipe (25-30mm), worked on mine.

Kt

Title: Re: RM250A NEED MORE BOTTOM END
Post by: pmc57 on October 19, 2010, 07:03:09 pm

My 250A's got more pull than a 15 year old boy, if you're in the powerband that is. Under that I agree it's like floggin a dead horse.

Title: Re: RM250A NEED MORE BOTTOM END
Post by: PRITCH39 on October 19, 2010, 07:52:01 pm

Hi all,

I agree it has a great power band but pulling out of a stop corner is painfull. I am not exactly a light weight at 120kg but it is unlikely i will be losing 40kg anytime soon ;D, so I am looking for a cheap fix if there is one. The bike gates hard and often will holeshot even with my weight.I have ordered a set of boyesen reeds maybe this will help, or maybe I should try a smaller front sprocket but didnt really want to change mid and top end. I think I may be asking to much.


thanks for the replies


Brian

Title: Re: RM250A NEED MORE BOTTOM END
Post by: DR on October 19, 2010, 08:41:12 pm

Brian, just remember, if all else fails, an RM370 will slot straight in thereby eliminating all of the lack of grunt issues ;D

Title: Re: RM250A NEED MORE BOTTOM END
Post by: BAHNZY on October 19, 2010, 08:53:19 pm

Ive a RM250C with Circle F pipe & muffler & standard porting running .40 over.
I had a similar issue and dropped back to a PE carburettor and the thing hauls off the bottom and through the middle. Sure the top end has dropped off a little but not enough that concerns me. In fact the bike is beyond my needs for outright power and i'm close to 120 kg geared up.