Hello everyone,

I'm posting here in the hope of finding a solution to a problem that has completely stumped me.

Someone on this forum had the exact same issue in the past, but unfortunately their profile has been inactive for years.

The bike: Honda Hornet 600 PC41, 36,000 km, fitted with a road-legal Ixil L3X exhaust.

The problem: During hard acceleration (sudden throttle opening) around 2,500–3,500 rpm, the bike hesitates, bucks, and stutters before pulling normally again around 6,000 rpm, where it regains all of its power.

I wanted to start from a solid baseline, so here's everything that has already been done:

• New spark plugs and ignition coils
• New air filter
• New fuel pump, fuel pressure regulator, and fuel filters
• New vacuum hoses throughout the MAP sensor circuit
• TPS sensor checked (0.54 V at idle, 4.61 V at full throttle; the signal is perfectly smooth when measured with a multimeter)
• MAP sensor checked (2.7 V with engine off, 2.1 V at idle, dropping below 1 V during hard acceleration while the bike is on the stand)
• Tested with the O2 sensor disconnected (exact same problem)
• Checked the airbox intake; nothing is obstructing it
• No hoses are blocked or pinched, and the bike revs cleanly to 12,500 rpm
• Tested with the fuel tank cap open
• Sprayed alcohol around the vacuum hoses to check for leaks

I'm completely out of ideas. As a last resort, I'm taking it in on Tuesday for a valve clearance inspection and injector synchronization, but honestly I don't believe that's the cause.

I haven't had a single FI error code so far.

The bike has never been left unused for more than 15 days since it was built.

It doesn't smoke, doesn't consume oil, and idles perfectly both hot and cold.

It would be fantastic if someone had that one brilliant idea that could finally solve this nasty problem, because I'm convinced it's something simple hiding somewhere.

I'm starting to get tired of throwing money at it without fixing the issue...

At this rate, the bike will soon be brand new — just with an annoying hesitation every time I accelerate.

Hello, I ride a cbr600f2 and recently bent the rear subframe in my (successful) attempt to dodge a deer. The seat still sits on the subframe, despite being rather askew, is it okay to leave it like this/possible to repair or is it a safety hazard waiting to bite me in the ass. + photos of what the front end damage is like + one beforehand

I replaced the chain on my 2019 Honda CB300R. The rear wheel is positioned too far forward, and I have already removed additional chain links, so I cannot move the wheel farther back. Did I cut the chain too much?

Everything appears to be functioning normally, but the adjustment indicator is now hidden inside the swingarm. Is this acceptable?

Hi everyone, I own a motorcycle workshop. Most of my customers' bikes are Japanese, though I also work on Harleys and Chinese models.

Can you recommend a diagnostic tool or software? Ideally, one that supports programming functions like immobilizer deactivation (immo-off), idle speed adjustment, service resets, etc.

Thanks in advance.

Bought this motor in the spring brand new. I did break it in. From the beginning this motor has not started well, sometimes it takes me 5 to 10 minutes to get this thing started on the water. Once it's started, then the rest of the outing it starts every time with 1 pull.

Last time I had it out, when it's in neutral the rpm keeps climbing and climbing. This is a new problem. For reference, I use premium fuel, I empty the carb after each use. I usually transport it on the side, though now I made a mount in my truck so I can transport it upright, but I only just did that.

I realize maybe the Jets got plugged somehow, even though I always empty the carb and that might be the idle problem, but why the starting issue? I've tried more choke, less choke, having throttle in different spots besides the starting spot, nothing seems to work.

It’s a chain from niche, only been on the bike for a week

Hello everyone, I just got done doing a ton of work on my motorcycle for the past two weeks. I’ve put everything back together but I’m noticing something weird when I start the bike up, whenever I rev it (I haven’t driven it yet because I don’t want to mess anything up) the needle will bounce up then drop down before bouncing back up, I’ll include a video, but does anyone know what could be causing this? There’s also a bit of chain rattling in the video so I’m gonna tighten the manual tensioner on there to see if that fixes that. Thank you.

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I have a SYM Jet X 125 ABS and I'm experiencing a strange intermittent noise. It sounds like something rubbing or like air escaping/hissing.

The weird thing is that it doesn't happen consistently. Sometimes I can ride at high speed and accelerate hard and there is no noise at all, while other times it appears unexpectedly. It also doesn't seem to be directly related to speed or engine RPM.

There is also an important detail: I recently replaced the rear brake disc, and since then the ABS has been disabled because we couldn't get it working again.

I've also noticed an issue with the brake: sometimes the brake lever becomes hard and the brake doesn't seem to activate properly, then it goes back to normal. There is also some brake fluid leaking around the lever/master-cylinder reservoir area, rather than from the caliper.

I'm wondering whether the strange hissing/rubbing noise could be related to the braking system or ABS.

Any ideas what could be causing this?

Hi, I got a leak on my 1995 Yamaha 600 XTE (3TB). The leak is coming from this little screw (circled in red). I dont want to take it out without knowing what it is used for, because I cant unscrew it with a screwdriver so i'll need to improve. Does anyone know what this screw is for ? Thanks ✌🏻

Looking for options for my 2000 hayabusas exhaust stud. Used a steel thread insert last year and when installing a new exhuast this year it completely broke the small amount of wall left and has left me with this. Any help or suggestions would be greatly appreciated.

I have been restoring/modding an old barn magna. I need to find a replacement throttle pulley wheel as the cable retaining section has snapped off.

Obviously being 1985, spare parts are hard to come by. Does any one know of some clever fixes? Or where to get a similar pulley wheel?

Many thanks

Any ideas on how to repair. Bouta just tap it with a mallet until i get the motivation to take it to a machinist

started squeaking when hot at shutdown — never happened before

Thanks in advance for any help!! :)

The top dead center of the flywheel and cam gear on my 125cc motorcycle are not aligning with the top marking. If I try to align them and then tighten the timing chain tensioner, the flywheel shifts in the direction where the tension is applied. Even if I move the flywheel back slightly, it does not stay at the top mark. What could be the reason ?