GS 450T Engine Noise

[Guest]

Hi everyone, I'm new to GS Resource website. I recently purchased a 1981 Suzuki 450T. It's in great shape, but had to do a few things to it such as new recitifier, battery and new tire. The concern I have is At around 3000 RPM I here this rattle or knock. I'm wondering if this is normal or is there something I should be doing.

https://www.youtube.com/watch?v=XQBWHkodml8&feature=youtu.be

[Rob S.]

That can't be normal.

[tkent02]

I haven't ever heard it in a GS engine before, but that sounds like a rod bearing is gone. They are not roller bearings like the older GSes, they have bearings like a car engine. Don't do any more damage, don't run it until you can fix it, or at least see if it's fixable before it gets worse.

I think maybe like a car you could replace a rod bearing by removing the oil pan, without taking the whole engine apart.

It might be easier and cheaper to find another engine somewhere.

[pete]

Maybe it doesn't come across in the video real well... but is it consistent like that all the time? It sounds to me like a vibration rather than a knock... are you sure something else on the bike is not just vibrating when the engine hits that point?

I have an annoying buzz around 4 -5K RPM but I know exactly what it is... it's a relay mounted behind my dash vibrating against the headlight binnacle. I just need to make a minor adjustment...

[albinosmurf]

Well I pulled the oil pan off and found metal shavings in there. So I am in the process of pulling the res of the engine apart to find what it is.

[Mekanix]

Counterballance shaft bearings. (most likely)
Crank bearings (less likely)
Connecting rod bearings are next on the list.

Pull the right side cover and see if you can wiggle the counterballance shaft at all.

[tkent02]

Ah, the dreaded counterbalance…..

[albinosmurf]

I'm am trying to get the right side off but the screws I dont think have ever been off so they are striping so easy. I am trying to find alternitive way to get them off without tap or dying them.

[tkent02]

Go a hand held impact driver? The kind you hit with a hammer? Pops them right off.

[albinosmurf]

Ok so it turned out it was my rod bearing. I purchased another engine in the meantime to stick in there while i rebuild the original.

[albinosmurf]

Got her up and going this morning with the new engine. Sounds great.

[winfield]

Excellent job! You must have some mechanical ability. Glad it didn't delay the enjoyment of riding too long for you.

[winfield]

... I have an annoying buzz around 4 -5K RPM but I know exactly what it is... it's a relay mounted behind my dash vibrating against the headlight binnacle. I just need to make a minor adjustment...

There's a hammer for that...

[pete]

Got her up and going this morning with the new engine. Sounds great.

Good job! Glad to hear it

There's a hammer for that...

Hahaha yes there is indeed! Although I opted for a different approach... a piece of rubber off-cut wedged between the binnacle and relay...