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piston slap

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The piston slap on the drz is driving me nuts. The previous owner had put in the high compression piston. To put a stock piston in there would I have to crack the case? If all I had to do was remove the top end I might be tempted to do it. The slapping is hear when on the gas, but not when I let off. The valves are perfectly adjusted.

Is there another way to get rid of piston slap?

Thanks.

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The previous owner rebuilt the engine and then sold the bike to me. The slap is loud. I don't know what a stock drz sounds like for comparision.

Does the stock drz400 have loud piston slapping?

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It shouldn't. Mine has 7k miles on the stock top end and it doesn't make any noise. I'd look closely at the bore for wear/out of round. If that's the case a new OE piston will slap just as loud.

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Most only do it if the idle is to low or your dogging it. Maybe it's time for a BB kit.

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I use premium fuel. It will slap when I'm at light load like when cruising on the trail or cruising on the road. It's very loud. I don't hear it at idle or when accelerating or decelerating.

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Just to be sure, you do run premium fuel right?

👍 what the hell does fuel grade have to do with piston slap ? can it cure rods knocking and valves changing holes too ? :smashpc:

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It will slap when I'm at light load like when cruising on the trail or cruising on the road. I don't hear it at idle or when accelerating or decelerating.

Sounds like you lugging it. DR-Z like to rev.

If it was "piston slap" wouldn't it be louder on acceleration ?

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my other post was asking this also. Mine is brand new, 500 miles only, and it is a knock just under acceleration not on decel or idling or leveled off rpm's.

Do brand new drz400's all have the knocking piston deal going on?? mine is not super loud knock, but you can definetely hear it under load.

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Sounds like you lugging it. DR-Z like to rev.

Yeah, i know when i try to accelerate low in the revs the bike feels like it gonna shake itself to death.

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my other post was asking this also. Mine is brand new, 500 miles only, and it is a knock just under acceleration not on decel or idling or leveled off rpm's.

Do brand new drz400's all have the knocking piston deal going on?? mine is not super loud knock, but you can definetely hear it under load.

The S is geared high,,, 15/44. If it is ridden in a high load low RPM like an old tractor it will lug and you will hear some piston slap. . Slip the clutch at start off, stay easy on the throttle til RPM’s build. If you short shift a DRZ especially an S model.. it’s ping (piston slap) it self to death.

Edited by E.Marquez

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Really when its warmed up 5 mins it should be pretty quite well to a point , ive just done another JE piston in mine this time ive had the skirt coated , even after over 20,000 miles the bore is still in spec. Without closely looking at the piston skirts u can easy miss the 3 points on the skirt wear it is worn.

Also i think oil has a big part in it , i change mine every 500 miles and ive gone back to normal 10/40 semi instead of 10/50 Silcolean with ester yes it shifted better but boy did it use oil !.

Id say pop the piston out and get the bore checked for ovalality and piston for wear. :smashpc:

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If you can't hit the gas and spin the tire, you're in too high a gear. If you're climbing a hill (nasty) and trying to tractor it put some speed behind it.

Or

Change over to 14/47 and forget about it.

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If you can't hit the gas and spin the tire, you're in too high a gear.

Mine barely spins if I rev the piss out of it and dump the clutch in first gear......damned Distanzias and concrete.:smashpc:

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Mine barely spins if I rev the piss out of it and dump the clutch in first gear......damned Distanzias and concrete.:smashpc:

Hard to remember these things work on the road too... fun everywhere!

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