unknown engine noise

Logan546

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Aug 24, 2015
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My 2002 blaster has always made a rattling sound, or a tick or a slight knock however you want to describe it, since the day i got it a few weeks ago. The noise gets louder the lower the rpms, like if i am bogging out in the snow barely keeping the engine running, the sound it at its loudest. But then normal cruising down the road or wide open throttle the noise is nowhere to be heard. My 2 friends have blasters also and both of theirs make noises too. My blaster always starts 2nd kick with full choke when overnight cold and always 1 kick when warmed up and it will idle all day long no issues. As far as i know my engine internals are stock. The engine seens to have great compression, but when you crank it over with your hand and listen, on the compression stroke you can hear a tick sound but it does it real quick and doesnt come back till the next revolution (when doing it by hand) On the outside my quad is bone stock. Except for an FMF silencer and fatty pipe. ItsOil injected (yes it works), stock airbox lid, TORS is still on the carb and the carb is stock too.
 
While they are noisey engines, you don't say if yours is similar noise to you buds or not. Description sounds like it may be piston slap or loose rod.. Might pay to investigate rather than waiting for it to blow.
 
While they are noisey engines, you don't say if yours is similar noise to you buds or not. Description sounds like it may be piston slap or loose rod.. Might pay to investigate rather than waiting for it to blow.

In case you are taking a poll, I fully back Larry's Shee on this advice.
Ticking in a Blaster is usually a piston skirt ready to break off and it is expensive when it does. Fix it now.

Steve
 
I just made this video 10 mins ago. It is 8:30am and this is a complete overnight cold start. In the beginning i show how the compression is by how hard it is to turn over by hand. It started first kick dead cold with full choke. Then i let it die out. Once warm it will idle all day long. The noise is audible in the video. Is it this a normal sounding blaster? Id like to think it is for how good it runs...
 
You're not paranoid and you have a problem. Unless you have the arms of a gorilla, (no offence) that kicker seems to be moving pretty easy. The only way to know for sure is to do a compression test ( with a quality gage) and measure cylinder to piston clearance. Look for about 125psi and no more than .004" clearance. If you already have the gage, it's going to cost about $7 for a base gasket and piece of mind. These Blaster engines run very close clearance between the crankshaft and the cases. If you break a skirt from piston slap, you have a 90% chance that you'll be buying new cases along with all of the other parts you need. To me, it sounds like bearing noise. While you have the cylinder off, check for any up and down play in the rod. Do this at TDC and BDC. You should feel no up and down play. You should also check your side to side play. Slide a feeler gage between the side of the rod and the thrust washer. .025" is worth concern, .030" is in need of a rebuild. While you're hands are dirty, pull the stator cover and see if you can move the flywheel up and down. This would indicate bad main bearings. Lastly, the counter balance shaft bearings could be making the noise. I have a bunch of You Tube vids that will help if you want to tackle this yourself.
 

OConnor Racing i tore down the topend, here is a video of the crank and piston and cylinder. What do you guys think? Please please say topend rebuild not bottom hahaha. The piston skirt does have some light scuffing, and it seems to be OEM?
 
For those of you that are too lazy to watch the video lol, the piston skirt has some light scuffs. Cylinder walls have some "normal" wear marks. Piston seems to be OEM (2002 blaster). The rod has a very tight clearence of .024" from rod to washer (tight meaning the feeler guage was hard to push down in so the clearence may be less) and absolutely NO up and down play. Im hoping i can get the cylinder honed/bored and slap in a wiseco piston... Or is this a bottom end rebuild too?
 
Update: i went to my local atv/mx race shop and explained everything and showed him the videos. He said it sounds like piston slap to him. The rod has no play up and down and has .023" rod play. He says it doesnt sound like a crank issue. After he miced the cylinder it needs bored. It has just a little to much room. So i gave him the green light to go .10 over on the bore and hone it for me. He is also getting a ProX piston and a cometic gasket kit. He said that after reassembly if it still makes the noise then the clutch cover is coming off and he will inspect the counter balance gear bearings cuz he did say that might also be it, but since my cylinder was a little out of spec i am doing a topend build too.
 
Sorry to revive an old thread but i just wanted to update the state of my blaster. Cylinder was bored .50 over which is alot since it was stock bore, it was out of round that much and tolerances were waaay off. ProX Piston. Reused stock gaskets, new spark plug, and fresh Maxima Super M oil. I have done 2 heat cycles with it now. I must say, it has no more knock whatsoever!! And compression is freakin amazing. She's fixed boys. Thanks for the help
 
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