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japcraplover89

fluttering in 5th gear?

20 posts in this topic

hey all, new to the forum but not new to riding or racing moto for what that matters, but im having a problem with my bike. in 5th gear my bike (2010 yz450f) starts to flutter out, almost like the RPMs are still riding but it wasnt catching gear. i ordered a new clutch which isnt here yet, but i ordered it thinking maybe my clutch was slipping since its the bikes stock clutch of two seasons now. after pulling the clutch, it doesnt appear that my clutch is toast. now im wondering if i have a flat 5th gear? has anyone else had a problem like this?

Tyler.

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Welcome.

Can you give more details? Anything and everything you can think of, even if it might seem irrelevant. Altitude? What type of terrain? How fast are you going in 5th when you notice the problem? It only does it in 5th gear? Answering all of these may or may not help, but the more info you can give, the better.

A guess is all I can venture at this point, but from what you've described, it seems to me that if your clutch were failing, the problem would be occurring in every gear.

Sorry I couldn't be more help at this point.

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it happens while riding track if i get a long enough straight to touch 5th gear, id say at speeds of 45mph? which is fairly low 5th. not that i had to touch 5th, but i was trying to pin point what the problem could be last weekend by playing with 5th. its like when i get to 5th, even though my RMPs arent screaming, theres some sort of throttle restrictor not allowing the bike to continue gaining momentum. i took the bike out on sunday after the problem arose on saturday, and had plenty of opportunity to play with higher gears while trail riding and it just seem to be worse. the bike runs fine with no problems in 1st-4th, 5th gear just seems to be finicky. ill install the Hinson when i get it on friday and test it out on saturday to see if the problem is still there, at which point ill be splitting the case and taking a peek at the gears. i just dont see why 5th would be burnt already, as i rarely use it unless im at the dunes or somewhere else open, which isnt often since most tracks in my area dont require 5th gear.

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From what you are describing, You need to replace 5th gear, which consists of 2 gears. Since you have kept riding with it jumping in and out of gear, be prepared to replace the shifrt drum (cam) and a shift fork as well. When your bike is acting like you are describing this one, continuing to ride, and jump in/out of gear, insures damage to components that might not yet be damaged

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Doesn't sound like it to me. Not the way it's described:

it happens while riding track if i get a long enough straight to touch 5th gear, id say at speeds of 45mph? .... its like when i get to 5th, even though my RMPs arent screaming, theres some sort of throttle restrictor not allowing the bike to continue gaining momentum..

If it was 5th gear popping in and out, it would be accompanied by a harsh jerking sensation, as if the chain were jumping over the sprocket, or you were rapidly fanning the clutch.

If in fact it is, though, the gears you would need would not be both gears for 5th. You would need the 5th and 3rd gear pinions (on the main shaft) and the number 2 shift fork. There's very little reason to suspect the shift cam of being damaged.

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Wonder if it could be a map sensor? High load low rpm and sensor choking eng out? Have you scanned it for codes?

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thanks for the replies guys, its got me thinking even more. i have NOT scanned for codes because i dont have a mapping tuner. i suppose asking around and finding someone who has one would be a good place to start.

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hey all, new to the forum but not new to riding or racing moto for what that matters, but im having a problem with my bike. in 5th gear my bike (2010 yz450f) starts to flutter out, almost like the RPMs are still riding but it wasnt catching gear. i ordered a new clutch which isnt here yet, but i ordered it thinking maybe my clutch was slipping since its the bikes stock clutch of two seasons now. after pulling the clutch, it doesnt appear that my clutch is toast. now im wondering if i have a flat 5th gear? has anyone else had a problem like this?

Tyler.

 

 

My 2010 YZ450 just started doing exactly as described. Did you ever figure it out? 

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I have a 2011 and a 2010 450 motors. Both have the exact same problem-the 4'th gears are broken. I hope you do not have the same problem!

 

 

IMG_3116.JPG

IMG_3117.JPG

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Crapolla!

 

Im going to pull the motor and split the cases this weekend. Hopefully the cause will be apparent.

 

Also researched the possibility of swapping for a WR 4th and 5th, Looks like you need the whole WR gear set as the splines are different.

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Turns out, my bike broke 5'th gear instead of 4'th as I had originally posted. i found the broken part when i pulled the flywheel. It was magnetically stuck to the flywheel.

Edited by yam314

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Crapolla!

Also researched the possibility of swapping for a WR 4th and 5th, Looks like you need the whole WR gear set as the splines are different.

Not true. You will need the WR (or Gen2 YZ450) output shaft and the 4 gears that make up 4th & 5th. That's it.

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Not true. You will need the WR (or Gen2 YZ450) output shaft and the 4 gears that make up 4th & 5th. That's it.

 

 

Oah... Because 1,2,3 are Pinion / Idler gears on the output shaft, got it!

 

Would you be willing to help me out a bit further and identify part numbers? is a 2010 gen2? I have a 2010. Figured a 12 WR 450 would be good to source gears from?

 

 

Here is the 10 Yz 450 trans...

10_YZ450.jpg

 

Here is a 12 WR 450 Trans...

Imagewr450.gif

 

 

So I need...

 

Output Shaft 

 

13: DRIVE AXLE ASSY -- Part# 2S2-17402-00-00
17: GEAR, 5TH WHEEL (21T) -- Part# 5TJ-17251-20-00
23: GEAR, 4TH WHEEL (21T) -- Part# 5TJ-17241-20-00

 

Drive Shaft

 

3: GEAR, 5TH PINION (25T) -- Part# 5TJ-17151-20-00

7: GEAR, 4TH PINION (22T) -- Part# 2S2-17141-00-00

 

 

Thanks!

Edited by ScottYo

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20140322_141426.jpg

 

 

 

If you want only the WR 4th and 5th, your numbers are correct, except that the 4th pinion has changed up to # 2S2-17141-20-00. 

 

There was a discussion of this matter earlier: http://www.thumpertalk.com/topic/954114-wr-4th-5th-on-a-10-yz450f/

 

 

Well.... it all looks okay to me The 5th wheel has a little scuffing where pinion engages but...  iduno . Any opinion?

 

!Thanks -Soctt

 

 

 

20140322_141439.jpg

 

 

 

 

 

 


 

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The 5th wheel doesn't play an active part in engaging fifth.  That function is done by the 3rd pinion.  The drive faces in the 5th pinion, and a bent fork are the usual suspects.  Look for wear at the center of the fork. ( ---> C ), usually means it's bent.

 

 

20140322_141439.jpg

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The 5th wheel doesn't play an active part in engaging fifth.  That function is done by the 3rd pinion.  The drive faces in the 5th pinion, and a bent fork are the usual suspects.  Look for wear at the center of the fork. ( ---> C ), usually means it's bent.

 

 

Hello GrayRacer, thank you very much for your help! I greatly appreciate it!

 

here are a few more pictures, shift fork and the wear pattern seem to look okay, I got a better picture of where the 3rd gear pinion engages the 5th wheel. I just ordered the WR 4th and 5th, output shaft and a YZ 3rd pinion, and shift fork 2 i dont see any glaring problems but hopefully just throwing some parts at it will cure the problem.

 

20140322_183417.jpg

20140322_183515.jpg

 

20140322_183649.jpg

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Are you sure that transmission was skipping in and out of 5th?

 

The fork looks immaculate.  Don't try to juggle with the whole transmission right now, just set up the main shaft, the shift cam, and the forward shift fork in the right crankcase half to find out how deep the 3rd pinion engages in the 5th pinion. 

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