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Do RM250s have noisier big ends than others?

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Seems to me they do, compared with YZs at least. I've pulled my cylinder to check conrod sideplay, and there's less than on the new Hot Rod replacement crank I bought a while ago! (RM - .48mm; Hot Rod - .55mm; out of spec at 1.0mm). No up and down movement either, and mains seems fine too. Maybe its the top end bearing?

Getting a Gorr 295 kit so want it to be all good, but now unsure whether need to bother doing the bottom end. Suggestions?

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Must be the little end bearing , if there's no play then there shouldn't be any noise . personaly if i was putting a 295 i'd put new mains in , just for piece of mind .

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Would putting an aftermarket water pump in make it quiet down? The supercharger sound gets kind of old on long trail rides. Sorry for the thread highjack.

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Probably not. The sound is the primary gear driving the water pump and exhaust valve governer gears. I just rebuilt my water pump, new shaft/gear, seal, bearings and exhaust valve governer bearings. Just as noisy as before.

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so maybe the noise is just the normal water pump sound? hard to think what else, as everything else is nice and tight. wato suggests changing bottom end while the barrel's off. but if big end and main bearings exhibit no slop whatsoever, is that really worthwhile? i know sometimes bearings may just collapse, but this wouldn't be the way most go, surely, not without slop first. (anything to get out of a multi-hour, multi-tool case-splitting job.....).

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the water pump/governor is sloppy and noisy as well as the kicker drive idler gear. sits kind of loosely behind the clip and makes a little noise, as long as my bike isnt pinging, im good!

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If it makes you feel any better, my motor has been completely rebuilt: top end, bottom end, all bearings, water pump shaft, seal, and bearing, and also the transmission. It still has the sound. It runs great though.

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Yup I agree I have a 00 rm 250 that's new top to bottom an it's noisy I spent almost 700 bux for nothing but a peice of mind lol.

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when i first got mine i thought something was wrong because if how noisy it was compared to other 2 strokes at the track, but the top end had just been done by Eric Gorr and he checked the big end for wear and everything was fine, so i just ignored it trusting that everything was going to be ok............. after a full season of racing, everthing is just fine (with a 265 kit i should add). the noise must be normal for these bikes. when you get the 295 kit put in, i'm sure he will check the play in the rod and let you know if that needs to be done too. He is very knowlegable and i don't think he would let a motor leave his shop if it needed to be repaired without telling the owner..

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