Suzuki Rm125 Bog

[DirtbikeRiderRaes02]

hi i have a 1998 Suzuki Rm125 2Stroke, with FMF gold series fatty and power core2 shorty on the back, i have Boyesen power reeds installed, with 168 main jet and 50 pilot jet, it bogs a little bit when letting off to go around the corner and when you get on it after coming out of the corner it bogs a little bit and then it starts to go, so i was wondering if i should go down to a 165 main jet? and what position would the needle clip need to be in?, i know for sure the pilot is right, and how many turns out from all the way in should the air screw be out? and the spark plug is almost a coffee brown colour, still a little black yet, (still rich) and for my gas i run 19 litres of fuel : 13oz of Amsoil dominator series synthetic 2 stroke oil.

 

Any suggestions on what do to do to get the bog out would be perfect and very helpful,

 

Thanks, DirtbikeRiderRaes02

[moto_psycho]

Tried cleaning your air filter? Simple, but often overlooked!

[DirtbikeRiderRaes02]

i will clean my air filters tonight, and take it for a ride and see how it performs, and i will let you know if it solves the issue.

 

Thanks, DirtbikeRiderRaes02

[mlatour]

Considering your engine is mechanicaly sound: fresh top end, reeds, clean air filter, good crank seals, silencer packing,

 

the cool fall weather has leaned out your jetting, going to a leaner 165 main jet will make it worse.

If you don't know the air screw's baseline setting, you cannot be sure the pilot jet is the right size.

 

At a minimum run the needle clip in the middle position, raise or lower the clip's position to adjust

the 1/8 to 1/4 throttle response: bog means too lean, stuttering / cutting out means it's too rich.

raising the clip = leaner, lowering the clip = richer

 

Take the time to read thru this recent thread:

https://www.thumpertalk.com/topic/1157132-jetting-question/

 

If you mostly trailride (even some recreational MX'ing)

Amsoil Dominator isn't the ideal choice as it has a higher flash point / works better in higher temps,

perhaps consider using Interceptor as it will be less prone to spooging & fouling at low speeds / cooler temps.

 

13 US oz of oil (about 385ml) to 19 litres of gas is roughly a 50:1 premix ratio,

hopefully you mostly trailride your 125 and not run it wide open for too long.

Edited November 9, 2015 by mlatour

[DirtbikeRiderRaes02]

I dont ride in fall weather, i just got my new reeds and i want to get it tuned before spring because I'm racing and i dont trail ride at all, track riding all the time

[mlatour]

In that case I'd look up the original settings for that model/year and start from there.

The only way it will be tuned 'perfectly' is if you tune it in the actual temperatures it will be raced in.

Every 10°Celcius rise/drop in ambiant temperature requires a jet change or setting adjustment if you want a spot-on perfectly tuned 2T race engine.

Edited November 9, 2015 by mlatour