Fried my clutch after 2 hrs of riding on a brand new bike.

wwillf01

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Heber Ut
Man you have to have something else going on... we have multiple stock oem yammi and ktm clutches with 100s of hours... we get way more out of them than in Dirt.

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Dec 14, 2020
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Man you have to have something else going on... we have multiple stock oem yammi and ktm clutches with 100s of hours... we get way more out of them than in Dirt.

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Yeah maybe, I'm not counting that out, I just have no idea what it could be. I checked the push rod and it's straight. There's no grooves in the basket. There is some grooves caused by the springs on the bolt studs. Ill attach a pic. I just cannot figure out why I'm burning through these. Maybe it's my off-road riding style of constantly slipping the clutch, even though I try not to on this bike.
 

wwillf01

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Yeah maybe, I'm not counting that out, I just have no idea what it could be. I checked the push rod and it's straight. There's no grooves in the basket. There is some grooves caused by the springs on the bolt studs. Ill attach a pic. I just cannot figure out why I'm burning through these. Maybe it's my off-road riding style of constantly slipping the clutch, even though I try not to on this bike.
You have stock gearing ?

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wwillf01

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Maybe someone can chime in if that is yz normal.. but if those are deep and keep the clutch pack from locking out I would say that's your culprit. This is speculation bit those are deep.

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Dec 19, 2007
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Those marks from the springs are strange considering you don't have many hours on the bike. I would check and make sure you got the right springs. If they are tight on the studs you probably aren't getting full spring force on the clutch pack.
 
Dec 14, 2020
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Those marks from the springs are strange considering you don't have many hours on the bike. I would check and make sure you got the right springs. If they are tight on the studs you probably aren't getting full spring force on the clutch pack.
Good point, though they are the OEM springs. Even checked length before install, exactly where they need to be at 48mm long.
 
Dec 14, 2020
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Burnt through my 3rd clutch this weekend. Thinking a rekluse might provide better oil flow and more frictions with stiffer springs. Don't know but I'm out of ideas other than that
 
Dec 19, 2007
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I'm out of ideas too. Is it possible your cable got kinked or stretched? I've seen some of the outer shieve stretch from a kink and then it acts kind of like a spring so the lever might feel like it's adjusted right but it's got a slight force still pulling the cable all the time.
Do you slip the clutch purposefully to make more power like riding a 125? Still it shouldn't matter the pro mx guys ride tsar way. I ride my 360 like that all day long with softer than stock clutch springs and the plates are purple but it still works perfect and I can tow sleds with it when they blow up. What's your altitude? My 360 makes more power than a 450 but I'm usually riding at 10k if you are at sea level you will be making big hp compared to most of us.
 

dirtrebel

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There’s 2 different thickness of fibers on the yz clutch are you paying attention to that and the order they go? Are you checking for free play down at the engine where the cable attaches to the arm on the case, not just at the lever? Run extra then check it again when it gets hot. Pushrod and ball bearing on the end of it good? Make sure you clean the screen in the bottom of the motor after a clutch fry, the oil filter itself sees very little debris as the screen gets most of it, I took out a Topend on my yz after I smoked a clutch because I forgot to check cable free play. Adjusted it after I noticed it slipping and kept riding to get back to truck, smoked engine. Upon inspection at tear down the clutch debris had clogged the screen which is pre oil pump (filter is after pump) so clogged screen = oil pump starvation

Sorry you are having so many problems
 
Dec 14, 2020
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Thanks. The oil screens filters and magnetic oil plug I installed all have little to no shavings. Yes, I installed the OEM clutches in the correct order (color coded) both times. The cable is fine and I run plenty of freeplay. I also run plenty of oil as you can even run a full quart without hydro locking the Yamaha. I ride near sea level.

What I did just discover is guys on regular motorcycles having clutch slippage issues with the rotella 5w40. My clutch definitely slips in powder at high rpms, thus generating heat. I'm thinking now this is mostly, if not all an oil issue. I'm also considering running the torque drive rekluse clutch pack with 3 extra frictions, that utilize a higher friction coefficient material. That, combined with better more suitable oil I'm hoping will fix all this. Apparently rotella changed their ingredients a few years back. Either way, gonna go with 10w40, either the rekluse brand oil or yamalube oil. Returning my extra rotella today.
 

wwillf01

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I use torque drive and really enjoy them in the snow. I buy Phillips 66 synthetic because it’s cheap. But it always holds up 10 hours an oil change on a pumped up engine..


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Nov 30, 2013
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Im not buying the T6 Rotella change. Ive used it for a lot of years more than the 5 ive been using it in my 501 and you would have a hard time convincing the pile of broken chain I have that my stock original clutch with over 300hrs is slipping at all. (chain brake was due to some mean clutch actions in a sticky spot haha)
 
Dec 14, 2020
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Well I can't figure what else it could be. If this doesn't fix it I'm selling the bike and getting into something else because I can't have an unreliable bike that goes through clutches every 3 rides that can leave me stranded. I'm all ears about other potential fixes but this seems to be most likely. The clutch design is different between husky and Yamaha so that could be why you've had better luck with this oil, not sure. It sucks I can't keep using it because it's cheap and I do oil changes often but pretty sure this is culprit. Dunno I'll post what I find out.
 
Nov 22, 2017
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Any chance you plumbed in the t-stat backwards? The temps you listed in the first post wouldn't cook an engine blanket like that. Also how you say it showing 180-190 but shoots to 210 asap when you stop. Anyways, seen it happen, same symptoms minus the fried clutches. Your cable and/or adjustment also seems suspect. It's def a you problem though, collectively I ride in a group with 1000's of hours on YZ450's and not a single clutch, ever.
 

wwillf01

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Where does your temp read from the radiator fin or the head via coolant ?


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Last edited:
Dec 14, 2020
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Yeah I'm not saying I've done everything perfectly to the bike, and I didn't install the thermobob. The reason why temps shoot up once stopped is because with the bike off there's no radiator coolant flow, or at least that makes sense to me, so residual engine temps are reaching the thermobob and that's why the temps go up when the bike is turned off. And yeah I know I'm the only one with this issue, that's why it's so weird. The thermobob lines seem correct but I'll take a pic to show you. Either way, I'm not losing coolant with the stock 1.1 bar radiator cap so it can't be overheating that bad
 
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