Little noise that doesnt sound right...

[MarkMRS4]

Hi guys,

A little background on whats happened.

My mates just bought a blaster - 2004 and the first day out the pistons blew!

So we set about a top end rebuild going for the numara stock size piston.

Now weve got everything back on and up and running, now theres a pining noise/knocking.

Posting a video for you guys to hear and offer some advice, the chain isnt connected up so ther is no load on engine at this point.

Any help would be appreciated.

Mark

 

[Motocrossguy17]

Video Of Noise For Mark.

 

[Blaaster]

Methinks a leak teat is required!

It sounds like it is gasping for gas!

Was the bore measured for wear?

 

[MarkMRS4]

Done a leak test, its holding psi solid for 8 mins

The A&F screw turned out 2.1/4 and sounded better also with the airbox lid off.

Mark

 

[Blaaster]

That answers the leak test.

What was the reason for re build.

 

[MarkMRS4]

We dont really know as we had just bought it and after 2 hours of riding there was a few knocks, then bang the top of the piston blew off!

Mark

 

[Blaaster]

Could there by any chance some piston bits that may have got into the crankcase?

Did you split the cases?

 

[MarkMRS4]

As stupid as it sounds we didnt... We didnt have the crank pullers or anything else to use.

We filled up with oil and flushed it 5/6 times by turning the crank , and let it drain over night so it was fairly clean to the eye anyway.

Mark

 

[MarkMRS4]

Anyone got anymore advice?

 

[Blaaster]

As stupid as it sounds we didnt... We didnt have the crank pullers or anything else to use.

We filled up with oil and flushed it 5/6 times by turning the crank , and let it drain over night so it was fairly clean to the eye anyway.

Mark

Anyone got anymore advice?

Split the cases, wash, better still replace the bearings.

 

[MarkMRS4]

Weve took her out to run her in and all seems good however she lacks in power, as in no power band.

When we take the airbox lid off it seems to come to life a little better! Sound, revs aswell. The AF screw is 2 1/4 out if this helps anyone answer why its lacking?

Mark

 

[Blaaster]

With the air screw at borderline 2 1/4 turns out could point to a slightly rich mixture.

Is the air filter clean and oiled with the correct oil if it needs it?

What size pilot jet is in there?

What is the needle clip setting and is it a stock needle?

Is the float level set correctly?

Does the carby dribble fuel?

Was the idle adjusted as per specs?

What pre mix ratio and what oil?

 

[MarkMRS4]

The carb doesnt leak fuel.

Havent checked any ov the other things youve said tho.

Mixture is 125ml to 5 litres of fuel.

Castrol Act>Evo 2T 2 stroke motorcycle oil