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Jankyl29

Beta2Stroke '17 300rr rattle sound, can't figure out

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Long shot. Is there anything inside the pipe like a small stone or, as happened to me, a silencer rivet that pinged off when I was repacking the silencer?

An old buddy of mine bought an XT500 with a "failed big end" for peanuts as a winter project. It turned out to be an engine mounting bolt nut rattling round in the metal sump guard.

I too have had a rattling power valve on a GasGas. Had to shim it up as it was flapping about. Worth checking that it hasn't got carbon buildup that's stopping it moving fully.

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Posted (edited)
On 8/1/2020 at 11:44 AM, Hubert Carpet said:

Long shot. Is there anything inside the pipe like a small stone or, as happened to me, a silencer rivet that pinged off when I was repacking the silencer?

An old buddy of mine bought an XT500 with a "failed big end" for peanuts as a winter project. It turned out to be an engine mounting bolt nut rattling round in the metal sump guard.

I too have had a rattling power valve on a GasGas. Had to shim it up as it was flapping about. Worth checking that it hasn't got carbon buildup that's stopping it moving fully.

Winner winner.

Well, just going to leave this all right here for the next beta with powervalve issues. Seen posts for ktms, gas gas all doing this, but no one seemed to have a beta do it until mine...

It IS the powervalve system. Sorry guys, it ain't the pipe. And here is how I finally got smart and figured it out...wish I did this weeks ago.

Pulled pipe off, pull 3 bolts and cover from right powervalve cover under pipe. Just manually moving mine was sloppy. Disconnected the rod to actuate the powervalve. Left cover off and put pipe back on, started bike and with the rod still disconnected lifted the powervalve up and there she was, back to the normal sounding rattles of a 2 stroke.

For whatever reason my powervalves are very loose, I'm going to replace all 4 bearings since they are original and go from there with shimming after. ..although the price for 1 of these bearings is pretty rediculous

 

Edited by Jankyl29
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Hi , I got the same noise from my Carapaks cage , I had to put some orings on screws contact surfaces to prevent vibrations .

This is not a mechanical noise coming from engine in my opinion , like bearings or clutch . It's a vibration coming from the exterior 

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Glad you found the problem!

Check the workshop manual for your bike on the Beta USA website under "Support". There is a section on assembling the power valve and adjusting the actuating rod for the correct fit.

I expect that your local bearing supplier will be able to get you the bearings much cheaper than OEM spares.

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On 8/4/2020 at 9:01 PM, Jankyl29 said:

Winner winner.

Well, just going to leave this all right here for the next beta with powervalve issues. Seen posts for ktms, gas gas all doing this, but no one seemed to have a beta do it until mine...

It IS the powervalve system. Sorry guys, it ain't the pipe. And here is how I finally got smart and figured it out...wish I did this weeks ago.

Pulled pipe off, pull 3 bolts and cover from right powervalve cover under pipe. Just manually moving mine was sloppy. Disconnected the rod to actuate the powervalve. Left cover off and put pipe back on, started bike and with the rod still disconnected lifted the powervalve up and there she was, back to the normal sounding rattles of a 2 stroke.

For whatever reason my powervalves are very loose, I'm going to replace all 4 bearings since they are original and go from there with shimming after. ..although the price for 1 of these bearings is pretty rediculous

 

The original part is pricey. However looking at the pictures it seems to be a standard 61900-2RS bearing. Try searching with that code and you'll get 80-90% off.

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Posted (edited)
On 8/4/2020 at 3:35 PM, Hubert Carpet said:

 

 

Edited by Jankyl29

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Posted (edited)

I got the new powervalve bearings in, started the bike back up....and the sound was still there !!!!!

Took it to the Beta dealer frustrated, just wanting to drop it off and the dealers are so booked they can't touch it this month. He spent 30 minutes outside with me listening to my bike and comparing it to his 17 300rr he had right there. 

His bike does not sound like shit like mine. He said, yes ITS NOT THE PIPE. He also agreed it sounds like it was coming from the powervalve.

So, took the bike back home. This time I pulled all the powervalve parts out of the cylinder, put the covers back on and started the bike. Its quieter, but the rattle is there. Its not the powervalves.

At this point I'm just putting the damn thing together, and riding the shit out of it until whatever is rattling either grenades the motor, or falls off.

Edited by Jankyl29
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Alright well I lied. I can't just let it go. My engine builder in PA said it sounds like extra piston to wall clearance and piston slap, which is beyond me because he just sent that cylinder out for work and charged me for it.

Bike is loaded up and im dropping it off at Bundy Motorsports in NC right now with permission to do whatever it takes to stop the noise. Ill let you all know what they find.

Edited by Jankyl29
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6 hours ago, Jankyl29 said:

Alright well I lied. I can't just let it go. My engine builder in PA said it sounds like extra piston to wall clearance and piston slap. 

Bike is loaded up and im dropping it off at Bundy Motorsports in NC right now with permission to do whatever it takes to stop the noise. Ill let you all know what they find.

So you buying a new top end?

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When I just dropped the bike off and explained the whole story, he said "I know you said the crank was just rebuilt, new piston and cylinder, but this sounds like piston skirt or rod bearing noise". They said they are going to have to pull the motor out, and totally tear it down again and inspect every part. He said it will be $800- $1000 minimum plus any parts.

The person in Pennsylvania who just charged me $813 to rebuild the motor, is not being helpful. I offered to pay double his rate, drive this bike to him and let him diagnose it. He said he is not taking in more work.

Looking at my receipt closer he charged me for main bearings, the cylinder work, New rings, gaskets and labor...no where is there rod bearing mentioned. If it comes out to be the rod bearing, someone is going to have alot of explaining to do.

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3 hours ago, Jankyl29 said:

When I just dropped the bike off and explained the whole story, he said "I know you said the crank was just rebuilt, new piston and cylinder, but this sounds like piston skirt or rod bearing noise". They said they are going to have to pull the motor out, and totally tear it down again and inspect every part. He said it will be $800- $1000 minimum plus any parts.

The person in Pennsylvania who just charged me $813 to rebuild the motor, is not being helpful. I offered to pay double his rate, drive this bike to him and let him diagnose it. He said he is not taking in more work.

Looking at my receipt closer he charged me for main bearings, the cylinder work, New rings, gaskets and labor...no where is there rod bearing mentioned. If it comes out to be the rod bearing, someone is going to have alot of explaining to do.

Ya, skip shop number two. Box up bottom end and send to Ken O'Connor racing. He will rebuild your crank and re-install into motor for way less than $1,000. His crank rebuilds are better than OEM with .0001 tolerance measured on finished product.

If the bike didn't already have 300 hours then I'd say skip all this effort, mix 32:1, go ride for another 200 hours until it blows. However, you did say it was drowned once so there's a possibility of bad big end bearing (crank bearing). Does the rod move up and down with the cylinder off the bike? I don't mean when the crank is rotating.

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5 hours ago, Jankyl29 said:

When I just dropped the bike off and explained the whole story, he said "I know you said the crank was just rebuilt, new piston and cylinder, but this sounds like piston skirt or rod bearing noise". They said they are going to have to pull the motor out, and totally tear it down again and inspect every part. He said it will be $800- $1000 minimum plus any parts.

The person in Pennsylvania who just charged me $813 to rebuild the motor, is not being helpful. I offered to pay double his rate, drive this bike to him and let him diagnose it. He said he is not taking in more work.

Looking at my receipt closer he charged me for main bearings, the cylinder work, New rings, gaskets and labor...no where is there rod bearing mentioned. If it comes out to be the rod bearing, someone is going to have alot of explaining to do.

If the engine showed no need to replace the rod at the time of replacing the main bearings perhaps the mechanic did nothing wrong except exercise poor judgment. If he would of replaced the rod at that time, the bill would of been a few hundred dollars more. It really comes down to a roll the dice. Hope it lasts without spending the extra money or spend money that maybe doesn't need to be spent.Tough call if you don't have deep pockets.

Edited by widebear

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