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yz85 grinding noise out of nowhere?

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I have a '02 yz85 and today I replaced the right side crank seal, head o-rings, and swapped out the head for a VHM performance head. I also put a FMF SST pipe on it with a FMF Shorty. The bike has been working perfectly all day, other than running poorly since i need to rejet. But no other problems then that. I came into the garage about 5 hours after riding, and noticed that when I turned the kickstart over, theres some grinding noise. It did not do this after I put it back together, it just started out of nowhere. While I was putting the clutch back together I noticed the shaft the clutch goes on moves in and out, I called my friend who has replaced the clutch on his 85 and he said it was normal and his was the exact same, so I didnt worry about it.  After I put it back together it was not making this noise, and didnt make it after riding either. Just started out of nowhere. Heres a vid to show what it sounds like. I don't remember it ever making this noise. I took the clutch apart to make sure nothing was wrong, I didnt find anything wrong except a little gasket maker that got onto the clutch since I put too much. Doesnt feel like theres any resistance while kicking it over, in the video the spark plug is out. Help?

 

Edited by Koray

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Sounds like something is rubbing in there, not like a crunching/grinding right? I’m thinking it’s probably not a bearing but maybe a bolt the managed to rattle loose or something else in the case? 

Idk maybe I’m just used to all the noises of my 4 stroke lol but it doesn’t sound very severe... how’s the oil look? Any shavings of any sort? 

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Take side cover case off and see if primary gear bolt come loose rubbing case. Had that happen on new yz250  lost power cause pv gear come off bolt wore almost threw case

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2 hours ago, Motox367 said:

Take side cover case off and see if primary gear bolt come loose rubbing case. Had that happen on new yz250  lost power cause pv gear come off bolt wore almost threw case

I’ll take the side cover off today and make sure that the primary gear bolt didn’t come off. Maybe I just under torqued it.

Edited by Koray

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11 hours ago, Motox367 said:

Take side cover case off and see if primary gear bolt come loose rubbing case. Had that happen on new yz250  lost power cause pv gear come off bolt wore almost threw case

I checked today and it was still tight. Not loose at all. 

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Pk check clutch hub for being loose,idler gear and kick start gear. Flywheel exc

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47 minutes ago, Motox367 said:

Pk check clutch hub for being loose,idler gear and kick start gear. Flywheel exc

I took the clutch out, the idler gear and kick start gear were fine, the flywheel is fine, nothing was making the noise, except when you spin the transmission you can just barely hear it, which im assuming is just normal from the gears spinning etc. The sound is much more noticable when you put the basket on, if that helps.

Edited by Koray

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13 minutes ago, Koray said:

I took the clutch out, the idler gear and kick start gear were fine, the flywheel is fine, nothing was making the noise, except when you spin the transmission you can just barely hear it, which im assuming is just normal from the gears spinning etc. The sound is much more noticable when you put the basket on, if that helps.

Gear on back of basket loose? 

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21 minutes ago, Motox367 said:

Gear on back of basket loose? 

I checked, it is not loose at all. I did find that it is not coming from the clutch or the transmission, but when I spin the crank over it is what is making the noise. I know the bearings arent bad, while I was changing the seal they had no movement whatsoever in any direction, anything else could it be? The only other things it could really be are the water pump, or the crank gear pressing against the seal(the little plate to stop the seal from sliding out was missing) I dont think its the water pump though cause it only has about 2 hours since I have rebuilt it(new bearing and seals) I guess the reason the noise was more noticable when the basket was on is because it would turn over the crank at the same time.

Edited by Koray

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Remove the exhaust and have a peak at the piston thru the port, are there any scratches or erosion on the edge of the piston ?

 

In some applications, that FMF SST pipe is known to be finicky on jetting and requires higher octane gasoline due to the higher combustion temps it creates. 

EDIT: combined with a VHM head (high comp insert?), even more important to keep an eye on any sign of running lean/hot.

 

I also remember reading that pipe must be used with it's own specific SST silencer,

having specific stinger length and diameter to to match the pipe's flow characteristics.

 

Edited by mlatour
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11 hours ago, mlatour said:

Remove the exhaust and have a peak at the piston thru the port, are there any scratches or erosion on the edge of the piston ?

 

In some applications, that FMF SST pipe is known to be finicky on jetting and requires higher octane gasoline due to the higher combustion temps it creates. 

EDIT: combined with a VHM head (high comp insert?), even more important to keep an eye on any sign of running lean/hot.

 

I also remember reading that pipe must be used with it's own specific SST silencer,

having specific stinger length and diameter to to match the pipe's flow characteristics.

 

I checked through the port and the piston looks brand new. It has about 2 hours since the last rebuild. I am running the bike at 93 pump gas, and the VHM head has the standard insert, not the high compression one. The silencer on it with the SST pipe is a fmf shorty, I don't know if that changes anything though.

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On 7/15/2018 at 9:21 AM, Christofehrzy said:

Sounds like something is rubbing in there, not like a crunching/grinding right? I’m thinking it’s probably not a bearing but maybe a bolt the managed to rattle loose or something else in the case? 

Idk maybe I’m just used to all the noises of my 4 stroke lol but it doesn’t sound very severe... how’s the oil look? Any shavings of any sort? 

Yeah, no crunching or grinding noises, sounds like just gears rubbing together. I dont think its the bearing cause the noise only happens with the basket on, if I put just the basket on without the inner hub etc when you spin the basket it wont spin the actual transmission(how it's designed), just the idler gear and crank. If i take everything off and spin just the crank, it doesnt make the noise, when I spin the kickstart, no noise, but as soon as I put the basket on it starts making the noise. I dont know what it is, I know as a fact it never made this noise before.

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