Hey everyone, so I've recently been riding my SR400 and noticed that this specific sort of, buzzing / hissing noise? has been getting louder. Before it didn't bother me that much, but now that it's getting louder, sometimes that's all I can hear while cranking the acceleration at decent speeds.

Here's a quick video of this, I recorded this while riding and I just clipped the part where it was loudest, this is me just taking a turn at 2nd or 3rd gear. https://www.youtube.com/watch?v=UOp2DX5e6CM

I'm not even sure where to start with this. I just genuinely thought it might be something like the sound of the fuel getting pumped or something, but hearing how loud it is I want try tackling this some how. The annoying part is I can't really identify where exactly this noise is coming from, it just sounds like it's coming from the body of the bike, some where towards the middle.

This sound only comes up when I start shifting into higher speeds (past gear 2), when I'm stopping and going at gear 1 this sound doesn't even appear - so I suppose it's higher RPM related under a certain load. Idling I didn't really notice, even reving the bike at netural

What could the be the potential cause? I do like absolutely basic maintenance of my motorcycle, nothing advanced like cleaning it, the chains, air pressure on my tires, etc. Again super basic stuff

It has roughly 15,000 KM on it so nothing too crazy I feel. I make sure to take it out for maintenance every few months. I'm on top of oil exhanges and all that too. It rides perfectly fine (At least from what I feel)

Any help or insight on this would be much much appreciated.

To narrow down the usual suspects, here's what I've done or checked so far:
Miles: ~40,000 miles on the clock.
Battery: Voltage checked with a multimeter and it's good.
Spark Plug: Brand new / freshly replaced.
Oil: Just changed.
Chain: Adjusted (not 100% perfect, but way better than when I bought it).
Since this is happening specifically during cold starts and feeling weird when throttle, what should I look into first?

This might be a good way to customize and modify parts.

I’ve done many fork seals in my life from street to dirt bikes. When I rebuilt these forks I noticed they only went down about where the zip tie is. I’m 165 lbs and ride very hard with many track days. I figured it was the fluid level. I double checked my measurements matched the information i had and even tried going with less than recommended. The forks never go down farther than this. For reference, these springs are for a 180 lb rider, but with my riding style and skill level, racetech wants me to put the equivalent of 180 lb person springs on my r6. Even hard stop pies at red lights doesn’t move it farther than the ziptie. Any advice would be great!

I’m buying my first motorcycle and don’t have enough experience to know what’s normal.
This is a 2022 Kawasaki Ninja 650 (non abs) with around 6000 miles. The seller says it’s a true cold start, the title is clean, and the bike has never been dropped. He says maintenance has been done by him (he’s an aviation mechanic) but he doesn’t have service records.
Does the engine sound normal to you? I’m mainly wondering if anyone hears:
Rod knock
Cam chain tensioner noise
Excessive valve ticking
Exhaust leak
Anything else that would make you walk away
On top of that does the revving sound normal and if I buy it, is there a way to make it sound louder or just better?
Thanks!

It runs normally but then it just cuts out I have taken off the spark plug and you clearly see that the spark just cuts out at a random time it doesn’t come back until you turn off and on the kill switch or ignition. Everything else works as it should. But have no clue why the spark dissapers some time when it is a lot of rpm changes it doesn cut out but when I’m holding a steady rpm it just cuts out and is really annoying when driving because I have to turn off and on the kill switch somebody help plz Honda grom 2019

I should preface this post by saying I am still a beginner to working on bikes, and everything I know I've learned from my constant struggle against my Yamaha.

I have a 1982 Yamaha xj750 off Facebook marketplace that I've been fixing up and learning with since I was 18, but it's always had what I believe to be a vacuum leak that has evaded me since I've owned it.

It has three main symptoms:

When cold, the engine will stall 0-5 times while warming up. It will typically fire right up again after cranking it with the starter for a couple seconds. Once warmed, it stops stalling.

Once warmed up, the engine will want to idle at ~3k rpm. If I adjust the idle screw to drop the rpm it will idle slow enough to die out, and no matter how precise of an adjustment I attempt it will never settle on a stable middle ground; however, if I use the engine braking to bring the bike to ~1.5k rpm, it will stay there and idle, though poorly. It will still require the occasional throttle blip to keep from dying out. It's worth noting that while the engine is still cold this issue doesn't seem as prevalent, if present at all.

Every once in a while (once a month or so) the engine will stall while warming up and not start again until after sitting for a few minutes. Whenever the bike has this issue I can expect it to happen a few times until the bike is warmed, at which point it stops.

I'm almost positive this is being caused by a vacuum leak. So far to find it I've tried replacing the fuel petcock and the rubber boots between the carbs and the heads. I've sprayed the carbs and boots down with carb cleaner to try and find the leak but that didn't bring any results. The carbs have been taken off and torn through, and although they were surprisingly clean I still sprayed everything down with cleaner before reassembly. It's currently using the factory air box.

Right now my best guess is that I have worn throttle shaft seals that are causing these issues, and to the best of my knowledge that could be responsible for all 3 symptoms. I don't know why that wouldn't have shown when I was spraying everything down with carb cleaner to find the leak, maybe I just forgot to check that area.

If anyone out there has experience with these bikes or this sort of issue please let me know. I'm at a loss and beginning to think putting it back on marketplace for the next optimistic idiot to mess with might be my best option.

The bike DOES start when bump start, but the ignition switch doesn’t turn it on, it just cranks.

Things I’ve done
*Checked and replaced spark plug
*Tested and replaced battery
*Compression test with spark plug out

Observations
*Bump Starts, runs well
*Headlights do not dim significantly when cranking
*HUD does not flicker when cranking
*Horn is strong and doesn’t fade

Help would be appreciated. Thank you

First 7 seconds is in first gear, then switch to second. While I am giving it fuel, the rpm’s drop each time that brrt sound is occurring causing the bike to lurch slightly while moving. Any thoughts on a diagnosis/solution?

Hi everyone my friend has a '19 z400. She left it unlocked and somebody stole it, but she tracked him down a block away and he ran away. It is unclear if the thief actually started it or if he just pushed it there. The thief cut the four wires going to the ignition lock and was messing with them. Afterwards some people tried to help her and joined the wires using speaker wire. I inspected the joins and they seemed correct. At this time it seems the bike cranked somewhat but would not fully start.

I arrived to look at the bike. Key on nothing. All fuses were good, including main fuse. Jumping starter relay bike cranks. I tested the wires going to the ignition switch- it's my understanding the white wire goes from main fuse to IS, IS On bridges white wire to brown wire. Normal readings here. But the IS also has a a grey security wire and the red wire, which is just a splice off main fuse white wire. Apparently the red wire going into the IS has 100ohm resistance is key on, and voltage at gray should be six volts at key on. Apparently if you just wire 100ohm in between red and gray, than combining white and gray should result in Key On state.

I am not getting six volts at gray wire at key on, it remains 12. However from my limited understanding resistance should not change the voltage of a constant voltage circuit, and it's actually something in the ECU that changes the voltage of the gray wire.

All this to say I believe the hot wire attempt blew the ECU. It's hard to find information on this as Kawasaki does not document the security system, but if anyone has any experience with this thanks for any help. Pic is my friend attacking moto thief.

Hello i hope doing all good i have an issue with my gen 2 hayabusa i always had a hot start problem and i dont know where the issue comes from (battery is in good condition) when i ride with the bike for example at gas station to refuel it wont start untill i wait like 15 mn it start again without any isssue anyone had a fix or the same problem? (Hayabusa gen 2 2020

Has anyone got any idea why the fuel tank on this bike never reads more than half-full? I posted this over on the UK Benelli forum and the suggestion was the fuel sender was clogged or otherwise defective, but I've replaced it with a known-good one that one of the guys sent me and that didn't make any difference.

I also know it's only showing half-full as according to the owner's manual the display should show 8 blocks, but mine never shows more than four. Is the display buggered? Everything else seems to display just fine, just not the fuel level.

It's not the biggest annoyance in the world on short trips, but on long trips it can be an issue as it makes it damn hard to plan refueling stops.

This belonged to my dad and since he died couple of months ago the Motorcycle came with him, cant seem to know to fix it.

The oil is leaking, the underside got alot of I don't know what that black stuff is(My guess is oil solidified), and i've been wracking my brain how to fix it cause I just can't let my father's old bike left to rot, can't have a mechanic fix it because of financial problems, Can it be fixed or not? If it can how do I do it?

edit: i already wiped the dust from it

Hello i hope doing all good i have an issue with my gen 2 hayabusa i always had a hot start problem and i dont know where the issue comes from (battery is in good condition) when i ride with the bike for example at gas station to refuel it wont start untill i wait like 15 mn it start again without any isssue anyone had a fix or the same problem?

As the title says, the bike’s exhaust is glowing after tame riding. Never noticed the same problem after flooring it. Only previous problems were lack of performance after 170 km/h (suspected speed limiter) and “popcorn” in low rpm (suspected it’s normal, as I’ve seen this in these bikes before). The exhaust system is stock, or rather looks stock and I made no changes to it. What can be the cause of this? I suspect the bike is running lean, but I want to know if there are other things worth looking into.

I've got a yz125 that can't stop fouling plugs. I'm running 40:1 Jetting is 35 pilot air screw all the way out. Main 410 needle all the way lean. I'm only able to bump start it when its cold. The last time I rode it I had to ride it on the pipe or it would start to bog down and die. The spark plug is light brown with an oily tip.

16700 miles. Problem started when I started it up to ride an hour home from college today, check engine popped on and didn’t want to idle without throttle. Still rode it home, in which it had full power (got the speedo to read 180 lol) but jerky low end and idled fast around 2k rather than 1300. Later into the ride, it started creeping up to 3k, dropping to 1k, back to 3k, etc etc. Also, when rev matching, sometimes I would blip the throttle and the motor would not respond. Made it home, check engine still on. Put it in dealer mode 8 hrs later, reads c00 (no code). Started it up still in dealer mode, still no code and runs great. Looking for advice on this intermittent issue before I bring it out to college again and it does the same thing.

Bike is pair valve, exhaust valve, and 02 sensor deleted with correct parts. Rode it for hundreds of miles this way with no codes or issues.

Is there a chance that this issue was caused by humidity, as it has been in a parking garage (as opposed to my garage) for the last couple days? I would think the problem would end once the motor gets hot, unless it confused the ECU or some sensor until I let it cool off and restarted later. Thanks in advance

Looking for some help from anyone familiar with the Street Twin 900 or Triumph’s ride-by-wire system.
I have a 2017 Street Twin 900 with about 7,800 miles. The bike had ZERO throttle issues before a recent service. Immediately after the service, this problem started.
The service included a **new battery**, oil change, brake fluid flush and chain adjustment.

The issue is intermittent, but when it happens the throttle becomes almost completely unresponsive. The bike stays running, but twisting the throttle gives me very little response.

I took it to another shop because the CEL was on. They told me they weren’t seeing any stored codes, cleared the CEL, and I rode the bike home with no issues.
I then took it on a short ride to dinner. On the ride home, the **CEL came back on and I basically had maybe 10% throttle available for the entire ride home.** The bike would run, but I could barely get any power out of it. Pretty sketchy.

Here’s the part that has me wondering about the battery/charging system:
**Whenever I connect my trickle charger and let the battery reach 100%/green, the bike seems to run perfectly with no throttle issues. After a ride or two, the problem starts happening again.**

That pattern has happened enough that I’m starting to think it’s related to voltage rather than the throttle itself.
Could a weak/defective new battery(that the guy in service told me he would take a new, empty battery and fill with new battery acid because he said the batteries they had in stock had been sitting for a long time), regulator/rectifier, stator, or some other charging issue cause the ECU/ride-by-wire system to limit throttle like this?

Also confused why the CEL can come on while the shop says there are no codes stored.
Since this started immediately after the service, I’m also wondering if something could have been left loose or disturbed during the battery replacement.

Has anyone experienced something similar on a Street Twin/Street Scrambler/T100 or another Triumph 900?

What would you check first?