1990 RM Fuel Mixture - Motorcycle-Journal Forums

Sicle · 07-27-2005, 07:36 PM

Hi Folks, I have a 1990 RM 250 and for the climate (British Columbia, Canada) I find the mixture ratio and factory setting a little to rich...lots of blue smoke...and my throttle has started sticking lately...I heard from a buddy that alot of people out this way tweak their mix (i.e less oil) to make the bike run a little leaner...the humidity is high in BC...but I really don't want to start playing around with it and accidently burn out my engine.....Has anyone else done this?

digipoi · 07-28-2005, 05:44 AM

Id just use the same mixture for your 250, probably around 50:1 between 44:1. Choose a ratio for gas/oil and stick with it. Mess with the jettings instead, that is where you should be focusing your attention in order to change between lean and rich conditions. What do you mean by sticky throttle? You may want to do a little maintenance on that throttle cable i.e. lube and check for wear. Regrease your handlebar where your throttle tube sits etc.

Dont worry as much about running too rich, its when youre running too lean is where you do the serious motor damage. You may have to clean your power valve more often, foul plugs, or repack your silencer alot though.

Dave, you got any ideas?

Dave2122 · 07-28-2005, 04:13 PM

You posted all the right answers so I have ntohing to add.

07-27-2005, 07:36 PM	#1 (permalink)
Sicle Newbie Joined: Jul 2005 Posts: 1	1990 RM Fuel Mixture Hi Folks, I have a 1990 RM 250 and for the climate (British Columbia, Canada) I find the mixture ratio and factory setting a little to rich...lots of blue smoke...and my throttle has started sticking lately...I heard from a buddy that alot of people out this way tweak their mix (i.e less oil) to make the bike run a little leaner...the humidity is high in BC...but I really don't want to start playing around with it and accidently burn out my engine.....Has anyone else done this?

07-28-2005, 05:44 AM	#2 (permalink)
digipoi Seat Tester Joined: Sep 2004 Location: Honolulu Posts: 84	Id just use the same mixture for your 250, probably around 50:1 between 44:1. Choose a ratio for gas/oil and stick with it. Mess with the jettings instead, that is where you should be focusing your attention in order to change between lean and rich conditions. What do you mean by sticky throttle? You may want to do a little maintenance on that throttle cable i.e. lube and check for wear. Regrease your handlebar where your throttle tube sits etc. Dont worry as much about running too rich, its when youre running too lean is where you do the serious motor damage. You may have to clean your power valve more often, foul plugs, or repack your silencer alot though. Dave, you got any ideas? __________________ 2004 RM250 2004 DRZ125L 2006 TTR-90E 2004 JR50 1993 RM250 1990 KDX200

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07-28-2005, 04:13 PM	#3 (permalink)
Dave2122 Sprocket Pilot Joined: Sep 2004 Bike: Which one of the 9? Location: USA Posts: 887	You posted all the right answers so I have ntohing to add.

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