I am pretty decent with this type of stuff, but I can not figure out worth the life of me what this is. It is really weird sound I get when I rev high, seems only to be noticeable in first gear. It sort of sounds like a rev limiter, like a ding ding ding ding sound at the top of 1st gear mainly. Sorry if im not explaining it to where it makes sense. I figured possibly it could be blowback, never had a bike that has had this before, so I am not 100% sure how a bike will run that has it. This is my first 125 2 stroke so I dont really know how hard the bike is running, because I have noting to compare it to. Anyone have any advice, I might take off the head and check everything out tonight. I think last time I checked the compression it was arounf 125 psi.... not sure if that is a good reading for a 125 or not. I can bring the front wheel up in first and second easily so the bike still runs strong it just acts up somtimes... like if i hit the road it wont pull strong till about 4th gear, than the powerband will finnally kick in.
Sorry for the rants, replies are much appreciated.
RM 125 strange noise at top of first gear
Started by
pastrana199rder
, May 31 2012 05:36 PM
2 replies to this topic
Posted 31 May 2012 - 07:22 PM
125 psi sounds low for compression to me.
About your problem with the noise (and I am guessing lack of power) is jetting.
2 strokes kind of blubber when they are too rich. Sounds like after you are wfo for a bit, it cleans it self out.
When a 2t is running rich, fuel can build up in the case. It doesn't take much to make it miss. When you crack the throttle open and it starts to rev up, the higher velocity airflow picks up the extra fuel that has pooled up in the bottom of the case and sends it into the cylinder. It will run like shit until all the excess fuel blows out of the case. This is known as "clearing out". Once the extra gas is gone, it runs tits.
My guess is you are way rich on the pilot, maybe the main or clip position as well.
Sometimes it takes a few gears of wide open running to clear out. Close the throttle and slow down, and the pilot jet (that is too big) is hard at work flooding your case with fuel again.
About your problem with the noise (and I am guessing lack of power) is jetting.
2 strokes kind of blubber when they are too rich. Sounds like after you are wfo for a bit, it cleans it self out.
When a 2t is running rich, fuel can build up in the case. It doesn't take much to make it miss. When you crack the throttle open and it starts to rev up, the higher velocity airflow picks up the extra fuel that has pooled up in the bottom of the case and sends it into the cylinder. It will run like shit until all the excess fuel blows out of the case. This is known as "clearing out". Once the extra gas is gone, it runs tits.
My guess is you are way rich on the pilot, maybe the main or clip position as well.
Sometimes it takes a few gears of wide open running to clear out. Close the throttle and slow down, and the pilot jet (that is too big) is hard at work flooding your case with fuel again.
Posted 02 June 2012 - 09:21 PM
Jethrobolas, on 31 May 2012 - 07:22 PM, said:
125 psi sounds low for compression to me.
About your problem with the noise (and I am guessing lack of power) is jetting.
2 strokes kind of blubber when they are too rich. Sounds like after you are wfo for a bit, it cleans it self out.
When a 2t is running rich, fuel can build up in the case. It doesn't take much to make it miss. When you crack the throttle open and it starts to rev up, the higher velocity airflow picks up the extra fuel that has pooled up in the bottom of the case and sends it into the cylinder. It will run like shit until all the excess fuel blows out of the case. This is known as "clearing out". Once the extra gas is gone, it runs tits.
My guess is you are way rich on the pilot, maybe the main or clip position as well.
Sometimes it takes a few gears of wide open running to clear out. Close the throttle and slow down, and the pilot jet (that is too big) is hard at work flooding your case with fuel again.
About your problem with the noise (and I am guessing lack of power) is jetting.
2 strokes kind of blubber when they are too rich. Sounds like after you are wfo for a bit, it cleans it self out.
When a 2t is running rich, fuel can build up in the case. It doesn't take much to make it miss. When you crack the throttle open and it starts to rev up, the higher velocity airflow picks up the extra fuel that has pooled up in the bottom of the case and sends it into the cylinder. It will run like shit until all the excess fuel blows out of the case. This is known as "clearing out". Once the extra gas is gone, it runs tits.
My guess is you are way rich on the pilot, maybe the main or clip position as well.
Sometimes it takes a few gears of wide open running to clear out. Close the throttle and slow down, and the pilot jet (that is too big) is hard at work flooding your case with fuel again.
This defiantly sounds right? what should i start with do you think? It is 100% that when i run it down the street at wot it clears out. usually kicks in around 3-4 gear. after that I can barley keep the front wheel off the ground. What should I start with, and is there adjustments for jetting before you actually switch the jet out? Also does oil:fuel mixture make a difference in performance? I thought 32:1 was too much oil for just putting around the yard, so I have been running around more like 40:1. Could that be an issue at all? I always get confused when someone says its running lean, because cant it run lean in 2 different ways? You can be running lean on premix, or you can run lean on jut gas in general right?
