=[YAMAHA YB 100 RATTLE]=

[Pol Anorl]

ok i have a 1990 yamaha yb 100 and recently ive gained a rattle that is very loud and is consistant from cold to hot,

ive taken the top end off and found the con rod has movement side to side,
2 questions
is this right and if its right how much play should it have.
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[Seb]

=[It's dead Jim]=
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2010 Triumph 1050 Sprint ST

[radical]

Sounds like the big end has died a death, to repair you will need to split the crank and replace the crank pin or oversize (machine) the existing crankpin and fit oversize bearings, that said you will need to replace the wee end and the main bearings plus crankcase seals to make it worth your while, is it worth it depending on the overall condition of the bike? there is no cheap fix.

[MarJay]

the con rod will move side to side a little, but its if you can make it move angle wize to the plane of the crank. If you can move it so that it is anything but vertical in the plane of the crank pin, then it is the big end I suspect. If not, then it might just need a rebore.

On my RD350 it rattled a lot, and it turned out the bores were worn oval and the piston was rattling up and down the bore. This is a recipie for disaster because eventually the piston skirt will shatter.

I'd say we need more information before we make a decision as to whether or not you need a bottom end rebuild. Personally I'd probably take it to a garage to have it looked at, at the very least. Even if you do the work yourself, it is better to get a professional to diagnose the issue rather than asking random people off of an internet forum.
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Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[27cows]

If the big end had gone, normally you'd see evidence (in the form of swarf) around the big end area. It'll be worth checking the amount of side to side movement with a feeler gauge to see if it's within tolerances (I've had readings way over on similar engines and they've still been fine - worth bearing in mind). A big end will usually knock rather than rattle - and quickly become terminal.

Could be bore wear. Make sure neither of the rings is stuck in their grooves. Also worth looking at the small end.
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The RXS100: vehicle of choice for Chuck Norris

[Pol Anorl]

I FIXED ITTTTTTTTT

it no longer makes the ratttle

i replaced the whole top end

and then the rattle was still there
so i thought ok take it over to be fixed

and on the way the rattle stopped ..

mainly because the big end bearing smashed to bits and shot up the side of my piston

ruined the piston scored the barrel killed the rings.

so now my engine makes no noise
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GOOD GAME BODYGUARD: https://i.imgur.com/8WePGgf.jpg
20:30:37 Pyro.: I don't sort of like men, I take every advantage to choke on dick.
Jewlio Iglesias: You live in Liverpool - Chances are, the front door has already been kicked off the hinges

[N cee thirty]

you replaced the bigend bearing then i hope ?
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[Pol Anorl]

[Blau Zedong]

[kingsknight]

bad times I hate that feeling when you know your bike is fucked. Riding along then.... bad sounds..... stop..... its fucked
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TS50 (sold) NS125F (sold) NSR125R-K (write off after 2 crashes) CG125 (nicked) XR125L-3 (Sold )-: ) DR125SM '11 (sold yay) XL125V '12 (In love with this bike) XT600E '04 (fun on the dirt)

[pepperami]

I`ts a YB100 so all is not lost .... there are still a good few of them around, so you should be able to get the bits .

they are not a complex bike so it should`nt? be to difficult to do? hopefully?, possibly? maybe?
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