Bad sounding engine. Big end gone?

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RempageR1

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Hi,

A Vmax rider from the Netherlands reached out to me with this video:


View attachment 1917532-ad650152c6434401aa6044f4b2ccc147.mp4


I`m afraid it`s a big-end failure or something similar. But before I tell him to get a new engine I`d like for you guys to also have a look / listen and tell me what you think.

Thank you.

Edit: I`m sorry this should be in the 1st gen motor topic, not the 2nd. Perhaps a moderator can move it.
 
Tell him to use a mechanic's stethoscope to listen on the engine where it's the loudest: bottom (crank, conn rods) or top (valvetrain).

A connecting rod big end in my experience is more of a metallic 'clang' and a crankshaft bearing is like a ball pein hammer striking an anvil.
 
Regardless of what is causing the noise some stripping will be necessary
With the exhaust off the sump can be dropped and the big ends can be inspected for obvious damage. I would also plastigauge the shells as well.

As Mr Medic suggests a stethoscope may help localise where the noise is coming from.

Have you checked the cam chain tensioners as performing as they should?
 
Regardless of what is causing the noise some stripping will be necessary
With the exhaust off the sump can be dropped and the big ends can be inspected for obvious damage. I would also plastigauge the shells as well.

As Mr Medic suggests a stethoscope may help localise where the noise is coming from.

Have you checked the cam chain tensioners as performing as they should?

I just asked and the sound is coming from the bottom of the engine. I`ll ask him to indeed drop the sump and take it from there. Thank you for the suggestion.
 
If he lays it on its side to have better access to the sump, be sure to tell him to remove the battery, if it's a lead/acid.
 
Thanks for your feedback and this week i will start with my Vmax which i own for just 3 weeks now. I just had two weeks vacation.
I hope that it is the cam chain tensioner as mentioned otherwise i will be facing the task to make a engine revision which i think it is going to be necessary.
Tip...i bought a digital guidance repair ebook with great pictures in it and step by step explanation.
 

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One thing you could check, when it makes that noise in idle, pull the clutch lever in and listen if the sound disappeared. If it did, your clutch basket bearing is worn out. Sounds exactly the same as conrods bearings.
 
Additionally to the topic, knocking sound from the 'bottom end', I had the same dilemma last year. My sound went away with the pull of a clutch. Took it apart, machined a new bearing for it with slightly tighter tolerances and left the grooves out. The grooves are there for ' red-light-stay-in-gear' -riders only. I'm not one. Works like a charm. Pics in other thread.
 
Actually that's funny because I was looking at buying a Venture for parts for this bike. Carbs are the same.
Carbs are similar. The 83-85 are smaller bore. The 86-93 are the same bore but missing the casting for the choke lever.
 
Hi,

A Vmax rider from the Netherlands reached out to me with this video:


View attachment 90843


I`m afraid it`s a big-end failure or something similar. But before I tell him to get a new engine I`d like for you guys to also have a look / listen and tell me what you think.

Thank you.

Edit: I`m sorry this should be in the 1st gen motor topic, not the 2nd. Perhaps a moderator can move it.
Thanks for reaching out and sharing the video. It's always a bit concerning when something seems wrong with a motorcycle engine, especially when it might be a big-end failure.

I'll be happy to take a look at the video and listen to the sounds. However, I'm unable to directly view or analyze videos as a text-based AI. If you could provide a detailed description of the sounds or any other information, I might be able to offer some insights or suggestions based on that. Additionally, it might be a good idea to have a professional mechanic or a local Vmax enthusiast take a look at the bike in person. They can provide a more accurate assessment of the issue.
 
I had a similar sound on my bike recently. Actually, it was more of a tapping/banging sound than in your video.

After crying a little bit on the inside, I reached for a very cheap mechanic's stethoscope like the guys suggested above.

All cylinders were happily swishing along like a sewing machine. Touching around the lower end sounded OK as well.

At the time, I managed to find a few posts here that discussed engine knocks that were actually caused by the inner sleeve of the exhaust. The stethoscope seemed to indicate the right forward pipe was making noise. I grabbed it with a glove on, and the noise seemed to dampen a bit.

Various guys here talk about hitting the pipe with a hammer to try and stop the noise before doing anything drastic.

It already had a dent at the bend where a previous owner had hit something, possibly causing this very problem, so I hit that same point with a ball-peen hammer, and the noise stopped!

Here was the noise Before The Hammer

He is the noise After The Hammer (a bit louder than the first clip)
 
Last edited:
I had a similar sound on my bike recently. Actually, it was more of a tapping/banging sound than in your video.

After crying a little bit on the inside, I reached for a very cheap mechanic's stethoscope like the guys suggested above.

All cylinders were happily swishing along like a sewing machine. Touching around the lower end sounded OK as well.

At the time, I managed to find a few posts here that discussed engine knocks that were actually caused by the inner sleeve of the exhaust. The stethoscope seemed to indicate the right forward pipe was making noise. I grabbed it with a glove on, and the noise seemed to dampen a bit.

Various guys here talk about hitting the pipe with a hammer to try and stop the noise before doing anything drastic.

It already had a dent at the bend where a previous owner had hit something, possibly causing this very problem, so I hit that same point with a ball-peen hammer, and the noise stopped!
Thanks for your comment. Greetings.
 

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