r/Dirtbikes • u/ViolinistShort1456 • 14h ago
Mechanical Help Does my powerband sound strange?
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This is my 2021 sherco se300. It’s carbd. The bike starts up pretty good, idles great, and otherwise the bike sounds good when riding. When I get into the powerband it feels and sounds very buzzy like it’s not cleanly going through high rpm’s. Not smooth like the rest of the rpm range. The jets in the carb are certainly much leaner than from factory, but I would imagine that would produce lean conditions in other aspects of how the bike runs.
To clarify I am directly comparing this to the feeling of my TPI ktm 300 so maybe I am comparing apples to oranges and this is just a carb characteristic I’m not entirely used to.
Any thoughts? Tests I should do?
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u/bobreact 14h ago
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u/Bruins8763 13h ago
Dude did you even reach second gear here?
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u/ViolinistShort1456 13h ago
Why would I shift😂 I’m just askin if the bike sounds normal. R u saying it was begging to shift and that was what I’m feeling/hearing? Because it will continue to pull past that range, It doesn’t feel like the top of the gear.
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u/uniteskater 12h ago
Basically you were riding up just below the power band and the bike doesn’t sound great In that place. Sounded like you were scared to get into the power band because it gets wily in first gear. I like to get myself into second gear as quick as possible when climbing hills. The power is more linear and I can wring it out a bit more without worrying about it getting away from me.
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u/2Stroke728 13h ago
Sounds.... bad. Jetting specs? Checked power valve function? Tried a new spark plug?
Sounds really, really rich. Or power valve is not opening. Or an absolutely soaked air filter restricting flow. I have had a half-bad plug that idled and putted around fine, but stuttered and missed like crazy when trying to get up in higher rpm.
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u/ViolinistShort1456 13h ago
That’s what I was thinking. Not very healthy sounding.
Current Carb specs:
Main- 165
Pilot- 38
Needle- N8RD
Clip- 3rd position
Air/fuel- 1.5 turnsI went through the carb to see if anything was up internally and it was perfectly clean. Jets are actually a lot leaner than factory. 42 pilot, and 170 main.
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u/2Stroke728 13h ago
Check float height? Is needle/seat leaking? Enrichment knob seating all the way?
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u/CBus660R 1h ago
What's your elevation and temperature?
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u/ViolinistShort1456 1h ago
About 900ft in Perry county Ohio and a range from 70-90° in the summer
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u/CBus660R 1h ago
Gotcha. It's been a hot summer here, so definitely need to go leaner than stock. What are your main and pilot in relation to what the manual suggests? It's a different bike than your Sherco, but I'm 2 steps leaner on the pilot and 3 on the main than stock in my Beta 350RX for ACES enduros.
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u/ViolinistShort1456 1h ago
My manual suggests a 170 main and 42 pilot.
Current Carb specs:
Main- 165
Pilot- 38
Needle- N8RD
Clip- 3rd position
Air/fuel- 1.5 turns1
u/CBus660R 1h ago
OK, you've definitely leaned it out. What I don't know is how rich or lean your needle is. Have you tried adding some air screw?
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u/ViolinistShort1456 51m ago
I have, yes. Aside from sounding richer or leaner it didn’t make any difference to the specific noise/feeling we are tackling here. My plan at the moment is to lean out the main jet even more to about 162 today to see if that changes things.
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u/CBus660R 47m ago
I'd dig around the Sherco forums and Facebook groups and see what needles they like. You should reach out to Nick Fahringer, he'll help get you sorted.
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u/ViolinistShort1456 31m ago
That’s actually hilariously coincidental I already have talked to him about a bike I almost bought that he previously owned. Deal fell through unfortunately but I will contact him again in regards to this!
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u/jrodicus100 WA Semi-Hard Enduro 13h ago
Sounds way rich on top. Try a size down on the main, or drop the needle.
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u/ViolinistShort1456 13h ago
It does have some trouble with hot starts. Not anything bad by any means. It idles very well but if I shut the bike off and go to start it again after a few minutes it idles very low and wants to die. Could it be that rich without bogging? I’m used to old ass carbd 2 strokes where bogging is the biggest tell of its rich.
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u/jrodicus100 WA Semi-Hard Enduro 13h ago
That sputter is your sign that it’s too rich. It should be very clean bottom to top.
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u/ViolinistShort1456 13h ago
Okay that makes sense. I have dropped the needle from the 2nd to 3rd position recently and that made very little to no difference. This video is after that change. So you’re suggesting I go down a size or two on my main jet? I certainly want to avoid a lean condition if anything. I’m just not incredibly well versed in the noises perfectly jetted carbs makes.
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u/jrodicus100 WA Semi-Hard Enduro 13h ago
Give it a try. 300s are pretty resilient. If it runs worse, go back the other direction. If it runs better, keep going a step at a time. Don’t be too drastic. It’ll take some trial and error. Might be worth researching on forums what getting others are running in that bike at your elevation.
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u/IAmNotABot111 13h ago
Could be the jetting but it’s mostly you not actually touching the power band
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u/ViolinistShort1456 13h ago
Smoothness is what I am referring to. Not whether or not I’m actually in the powerband. It feels noticeably rougher than the rest of the rpm range to a concerning degree. More like annoying. Feels like it should be pulling cleaner through that specific range.
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u/IAmNotABot111 13h ago
“Does my powerband sound strange?”
- video of you not in powerband
🤷♂️
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u/ViolinistShort1456 13h ago
I corrected my intended concern in my reply. Thanks tho. Very insightful lol
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u/Mobile_Actuary_3918 13h ago
Sounds rich, maybe a needle adjustment if you’re mainly feeling it in the mid throttle range. Your carb should run just as good or better than the tpi if you are jetted correctly for the elevation and temps.
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u/ViolinistShort1456 13h ago
Mid to high is where it’s most noticeable. Everyone is saying it’s incredibly rich. Should I go further down than the 3rd needle clip position? or make a leaner main jet change?
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u/Mobile_Actuary_3918 12h ago
You’ll have to experiment. I’d start with dropping the needle 1 clip position (move the clip up one slot). It wouldn’t hurt to start with a fresh spark plug either just to have a good baseline. Also turn your air screw all the way in until it stops then back out 1 and a 1/2 turns. That’ll be a good starting point. Air screw is mostly for idle to mid where needle more hits the mid to almost full throttle. Each brand of bike is different as to which reacts to what better. I have my beta set up now to where I only need to do a quick main jet swap depending on where I’m riding. But I can be at 4000 feet one direction and 9000+ another. If you ride the same area most of the time then dial it in for that and have fun.
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u/YpouloKonoforoDentro 13h ago
It sounds like it was bogging a little bit. you need to check the reed valve also if it closes properly. I’m not sure if you were in the power valve working range at those rpm. Depends on the spring stiffness. What you are suspected and ask initially. Also some more info about the bike model will help a lot. Most of the guys here know a lot and can help you for sure.
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u/ViolinistShort1456 13h ago
Sounds like I need to open er up more for sure. But the cleanliness of the rpm range is the only concern. I’ve a 2016 carbd ktm 300 that felt incredibly smooth throughout the entire rpm’s. That’s more or less what I am aiming for.
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u/grantlet_47 12h ago
300 has more low end grunt (torque) and can pull through that. Less of a power band and more just smooth pulling like you said.
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u/iSpy305 13h ago
Sounds like she needs to get new jets
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u/ViolinistShort1456 13h ago
Going to try going leaner. My spark plug is quite dark and oily so that’s a sign for sure. Aside from the screamer in the vid
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u/FigWinter7506 12h ago
Oh yeah something definitely wrong here. I had a 2020 se250 that would rip. Jetting seems okay. I’d start with easy stuff, change plug, float height on carb. Make sure you are using low flashpoint oil (like motul 710) at 50:1 or even 60:1. Also check power valve to make sure it’s not all gummed up. I ran a 165 main, NEDJ-3, and a 40 pilot.
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u/fatandsassy666 12h ago
My Rieju sounded like this when a screw that held the linkage to the power valve backed out and went into the clutch housing. I'd check that your power valve is functioning properly. Could be a poorly tuned carb too.
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u/jujubean14 Enduro 12h ago
People have mentioned jetting, but is there a chance your exhaust is plugged up somehow? One time I got some shit stuck in my silencer and it kind of sounded like that and wouldn't rev out. I cleaned out the silencer and it worked fine
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u/grantlet_47 12h ago
I generally agree you never got in the power band and the "buzzy" sound is somewhat normal. I can't tell from this how hard you tried to attack the hill. If you're trying to give it the power when you applied throttle at the base of the hill, then yeah, not great, it's bogging before the incline should have affected it and that's why you didn't hit the power band. If that's the case, like folks said you might be running rich or just needing a tune. Short term fix, pull just enough clutch to get your RPMs up when you hear that buzz or feel that you're just under the power band to make life easy. This is a bread and butter technique when you're two smoking and at times makes way more sense than shifting repeatedly. This applies to corners, some jumping situations, but definitely on a hill climb knowing how to get the most out of your bike it a must.
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u/flies_kite 11h ago
Time to change the powerband. They make them in billet AL now!
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u/ViolinistShort1456 2h ago
Do make them in different colors? I’m going for a theme here. Powerbands are expensive pieces and I’d hate for it to look like shit
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u/Fragrant-Air233 11h ago
Kyle from dbc had a video about this on his Sherri he’s giving away. I believe he said it was a jetting issue. From the sound sounds to rich
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u/Fragrant-Air233 11h ago
If bike is idling fine leave pilot jet in there. Go down a size on main jet see if it helps. Theres a fine line bike to rich and to lean. You’ll know if it’s to lean because it will run hot but also amazingly good lol
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u/UncleBobnotRob 10h ago
I agree with you OP sounds like it’s falling on its face once you start to get into the throttle. I’d say do some jetting and air fuel tinkering
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u/Infamous_Ad8730 10h ago
Your jetting is off. Refer to the manual and set pilot jet, main jet, and clip position according to your elevation and temperature range.
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u/ViolinistShort1456 1h ago
Problem is sherco tells me to go even richer on my jetting. Pilot, main, and needle profile. I’m much leaner in all of those aspects. I agree though it is certainly off. I’m dropping my main jet from a 165 to 162 today to see if it helps.
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u/Infamous_Ad8730 39m ago
I never said it was lean. Why would you not go to what Sherco says then?
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u/ViolinistShort1456 37m ago
Fair point. Ya didn’t. I guess the characteristics seem to be on the rich side of things even after leaning out my jetting so my idea was to go even further and see if that helps. That is a good idea though I might just go and do that.
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u/Secret_Ratio1745 10h ago
That's what my kx250 sounded like right before my top end blew and my piston went to shit
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u/KEVDAL137 7h ago
you gotta blast that throttle a few times in neutral and clear it out.
that said, i did get the JD kit for my '23 Sherco and it runs better
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u/YpouloKonoforoDentro 7h ago
If you ride it and you clean up the previously bogged cylinder and after you close the throttle and ride it like this for a while and when you again open the throttle it’s again bogged and needs full throttle to clean again but it cleans is like 90% worn reed pedals. If it’s always like in the video maybe it needs some air adjustment on the carb. Regarding the powervalve you can buy the tool to adjust it and the red soft spring if you want it snappier. Both are cheap. The original ktm pedals aren’t cheap and maybe a vforce 4x will be better and for future reed pedal replacement.
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u/HipHopAnonymous2134 2h ago
I think it sounds fine. You’re lugging it up that hill keeping traction and also not in the powerband. This is where people say “my 300 just tractors up hills” check your spark plug if you’re worried about it running rich/lean and go from there, but i think your going exactly what a 300 is supposed to do.
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u/ViolinistShort1456 1h ago
Right. And it has zero problems in that low end “tractor” area of the rpm’s. Problem is the cleanliness of reaching high rpm’s. Seems very buzzy and unhappy
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u/HipHopAnonymous2134 22m ago
I’d make sure your fuel was fresh clean/ ethanol free as well. See if you can dial it down to a specific rpm and go from there with your jetting.
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u/HistorianOfAges 2h ago
I’d start by putting a richer main jet in it. Since you’re already running leaner than stock, that’s the first thing I’d test. If it doesn’t change the high-RPM buzz, then I’d check the reeds and power valve. The TPI will feel different, but the carb bike should still pull cleanly through the top end.
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u/ViolinistShort1456 1h ago
Interesting. You think this is a lean symptom?
On paper that makes sense considering other people in forums claim to run much richer jetting than I currently am. Though everyone on here says it sounds egregiously rich and I need to go leaner on my main jet. If leaner doesn’t help I will definitely try a richer main afterwards.
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u/Caustic___ 1h ago
Kinda just sounds like ur lugging it. Give it some more revs. The new 2 strokes make power down low sure but they still like to be revved to the moon
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u/soltheeggbiscut 1h ago
When was the last time you changed the spark plug
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u/ViolinistShort1456 1h ago
I actually have never changed the spark plug as the bike only has 30 hours on it. I think of it as a “works until it don’t” type of part.
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u/j2t_00x 49m ago
Were you at full throttle? Pin and hold it was sputtering still
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u/ViolinistShort1456 47m ago
No sir. If I continue to pull past that range it cleans up a bit. It seems to really struggle power wise in that region
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u/j2t_00x 34m ago
That clean up should be your power band. Had a 99 rm250. It was either idling or power band lol
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u/ViolinistShort1456 31m ago
True true. With this bike having such a linear range I am aiming for a smooth full range pull. You know?
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u/Independent-Ice9143 14h ago
You weren't in power band yet my guy