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2017 Factory 300 banging noise from engine


mightychub
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Hi all,

This may have been covered but here goes. I have 30 hours on the bike and everything was fine from new but once it was run in it started to bang under load from long step banks. The bike shop sent me a new CDi thinking this was the issue all was fine last week and until the later part of today the banging came back after the bike was really hot. This banging noise does not happen on the new 19 model so I am lost to why it is doing it. Has anyone got any ideas to what it could be? I had betas years ago and not had this kind of issue I have only just come back into the sport and with it banging like it is am worried it's doing damage to the bore or piston.

Edited by mightychub
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Preignition/pinking?? Take cylinder head off and clean combustion chamber and top of cylinder. No soot or deposits is allowed after cleaning.  Check carb settings. and clean all jets and and drillings in carb body. Check ignition setting.

/Carl

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Hi everyone I have been running it on highest octane the bike has only done about 25 hours. I spoke with Acklams where I got it from and they have told me to take it back to be looked at as it should not be that bad after only 25/30 hours their mechanic said it could be a few different things so hopefully it will get sorted. And this why I buy from a great shop like Acklams their after sales service is just bang on. Thanks everyone for your suggestions  

Edited by mightychub
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Just wanted to add to this post. The bike has now been looked at and it seems the new CDi that they replaced a month ago has gone so they have ordered a new one from the Beta factory so hopefully this will resolve the issue.

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Hi everyone latest update as of today 25th June the shop can not fix the issue they have replaced electric stuff and the issue is still there. The bike has to go back to Lampkin imports for assessment as it is now up to them what happens. I have no idea when I will get it back. I am gutted and this is the first time I have ever had an issue with a Beta. It's going to be interesting to find out what the problem is.

 

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I have now spoken to John Lampkin who has informed me after having a good look at it that it is normal? He says as the bike goes between low jet and high jet there is a moment that there is hardly any fuel going into the bore so when it reaches the point of getting the fuel the piston will slap a bit. I still find it very disconcerting that the piston slaps that hard but he says it's a common thing on the new Betas and not to worry about it.

I have asked a few folk who have 18s and 19s they all say they don't have it happen on their bikes. It kinda makes you want to go get a new one but mine is still new and I should not have to get rid of it.

I really don't know what to do for the best because to my ears it's a nasty noise 

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3 hours ago, mightychub said:

I have now spoken to John Lampkin who has informed me after having a good look at it that it is normal? He says as the bike goes between low jet and high jet there is a moment that there is hardly any fuel going into the bore so when it reaches the point of getting the fuel the piston will slap a bit. I still find it very disconcerting that the piston slaps that hard but he says it's a common thing on the new Betas and not to worry about it.

I have asked a few folk who have 18s and 19s they all say they don't have it happen on their bikes. It kinda makes you want to go get a new one but mine is still new and I should not have to get rid of it.

I really don't know what to do for the best because to my ears it's a nasty noise 

Mightychub,

I don't know how sensitive your ears are, so maybe the noise is normal.  But if your mates think it is not normal, that is a strong indicator that something is wrong.

I would insist on some written documentation from Lampkin stating that there is nothing wrong with your bike, and that if a problem exists in the future, he will fix it on his dime.  If he is confident in his diagnosis, this should not be a problem.  Can you record the noise, if so, maybe forwarding the noise file to Beta would get additional opinions.  Obviously, in these situations, we are looking for a fix, and additionally, peace of mind that the problem does not exist.

At a minimum I would:

1.  Buy the highest octane "petrol" you can find, and add a double or triple dose of octane booster to it and see if the noise goes away.  Aviation gas (112 octane in the US) is what a friend who has ridden Beta for decades swears is required, unless you have the Beta 250 which is their lowest compression motor.  You could also make up a small batch of gas-oil mixture that is richer in oil and try that.

2.  If Lampkin is right, that the noise is caused by carb jetting, one would think that making the carb jetting richer might help reduce the noise.  Hopefully with the bike still running well.  A quick experiment might be to "choke off" the air intake area (with some duct tape) to simulate a clogged air filter to see if that changes the noise.  Additionally, remove the air filter completely to lean out the mixture.  Might not help, but easy and quick.

3.  Pull the head or use a boroscope to look for signs of detonation.

4.  As Dan has suggested, the Jitsie water pump impeller may help.  Does the problem only occur when hot?

I'm no Beta master, but experimenting should tell you something.

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