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08 CRF450R Transmission Shifting Issue

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Guys, I need some input from those of you who are familiar with these bikes and the problems they may pose. 

 

I got my bike back together after tearing it apart to redo the suspension on it and while at the track I noticed that when I would upshift the transmission would grind much like a car with a bad synchro. Now our bikes do not have synchros so I realize that's not the problem. My first suspicion was that maybe, since I'm 6'8" and have massive feet, I've landed on the shift lever or hit it with my big ol' feel and bent a shift fork. That must be it. 

 

I tore the motor down last night and as I removed the right crankcase cover to get to the clutch and kickstart mechanism everything was going well. I started fiddling with the ratcheting mechanism and the shift rod that crosses through the crankcases. Everything felt ok. As I continued dismantling I noticed that part number 10, in the picture below, was laying just inside the lip of the right crankcase. I'm not sure if I bumped it out while I was fiddling around as I have never taken this engine apart before. Is that something that can happen? Is it something that happens often? 

 

ShifterMechanism_zps4ff77ec1.png

 

I continued and eventually split the cases to inspect the transmission. I was hoping the problem would be easily visible but I couldn't find anything. The shift forks do not seem to be bent. Does anyone have any input? 

 

Thanks,

 

Wile C.

Shifter Mechanism.PNG

Edited by WileCyot

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ive done this myself reassembling an engine, its pretty easy to do. Now i use a bit of grease to help hold #10 in place while installing the shift axle and side cover. check that the arm on #18 isnt bent, put it back together and you should be good to go.

Edited by nzgsr

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You wouldnt be the first guy to knock #10 off of #9 while the engine was still assembled. Doing this will kill most of the required travel of the shifter arm necessary to rotate #9 up or down far enough for a complete shift. Look inside the clutch cover and check the boss thats cast into it to make sure its not broken or worn off somehow that it allows the shifter shaft #18 to slide in enough to release #10 from #9.

 

Put the sleeve back on the shifter arm, push it through and see if when you hold it in place that you get a full shift. Now, if this isnt the case, a bent shift for a broken shift drum, or both, will do the same thing.

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. I have had my 08 transmission apart a number of times. In fact had a problem recently that sounds a lot like yours that had me splitting the cases 2 times in last 3 weeks.

 

question  -does it "grind" shifting into All gears or just one or two??

Edited by lowmass

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You wouldnt be the first guy to knock #10 off of #9 while the engine was still assembled. Doing this will kill most of the required travel of the shifter arm necessary to rotate #9 up or down far enough for a complete shift. Look inside the clutch cover and check the boss thats cast into it to make sure its not broken or worn off somehow that it allows the shifter shaft #18 to slide in enough to release #10 from #9.

 

Put the sleeve back on the shifter arm, push it through and see if when you hold it in place that you get a full shift. Now, if this isnt the case, a bent shift for a broken shift drum, or both, will do the same thing.

 

I'll take a look but as of now when the clutch cover and right crank case cover were off everything shifted fine when I held it all together. Full up shift, full down shift, etc. 

 

 

. I have had my 08 transmission apart a number of times. In fact had a problem recently that sounds a lot like yours that had me splitting the cases 2 times in last 3 weeks.

 

question  -does it "grind" shifting into All gears or just one or two??

 

As far as I can remember it "grinds" on all gears. It's like a buzzing sensation. The dogs are rubbing corners against one another but are spinning at a speed such that they do not engage only graze.

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ok well I lost 3rd gear. It broke a chunk out of my shift drum. Before this it was notchy and grinding to shift. Replaced drum and within 10 min it broke out again. opened motor again and got serious. The dogs on a number of gears were rounded to point where they would not latch into next gear but rather push away. This is what broke the drum twice. Replaced gears and now shifts so well I wish I replaced all the gears.

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ok well I lost 3rd gear. It broke a chunk out of my shift drum. Before this it was notchy and grinding to shift. Replaced drum and within 10 min it broke out again. opened motor again and got serious. The dogs on a number of gears were rounded to point where they would not latch into next gear but rather push away. This is what broke the drum twice. Replaced gears and now shifts so well I wish I replaced all the gears.

 

The dogs being rouded off will act like a wedge against the shift forks and drum.

 

If the trans is rattling the shift dogs like that the engine needs to come apart and see whats what. Typically when I replace gears because the dogs are rounded, I'll replace the drum and forks too.

 

If you get clean shifts with the clutch cover on, but it still rattles the drive dogs and not engage cleanly, pull it down and start inspecting the trans very closely. It doesnt take a lot to make the gears useless. Ive got some pretty good pics of what to look for if you want them.

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The dogs being rouded off will act like a wedge against the shift forks and drum.

 

If the trans is rattling the shift dogs like that the engine needs to come apart and see whats what. Typically when I replace gears because the dogs are rounded, I'll replace the drum and forks too.

 

If you get clean shifts with the clutch cover on, but it still rattles the drive dogs and not engage cleanly, pull it down and start inspecting the trans very closely. It doesnt take a lot to make the gears useless. Ive got some pretty good pics of what to look for if you want them.

 

Mine isn't rattling per say, I think I've found the problem but feel free to post up the pictures. Any input is always welcome.

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Shawn could you give us a little edumacation?  I can clearly see the deformation on the driven side, but can't see any difference with the dogs.

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The "Deformation" on the driven side might be just the wear/ machining marks and the way the light is reflecting. It looks like the driven side was too soft and actually deformed. Not likley but supose possable as i dont know the transmission in pic. If that is what happened here then that is a serious design flaw.  The driven side pics show some rounding off of the dog edge. It is not a huge difference ( compare it to other side of dog) . You can get away with a little rounding off BUT there comes a point where it will be enough to 'kick back" away from the gear its trying to mesh with.

 

However depending on your speed this usually happens with 2nd,3rd and 4th gear long before the others as they are used so much more. IN  Wile's case he says it is doing it in ALL gears. This leads me to believe there is something else going on. Something like the shift mechanism is not moving full travel somehow.

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I've got a perfect trans from an 04 on ebay right now really short money, if you need any parts.

 

I have the shift shaft and #10 sleeve too

 

I believe you would have to swap the entire trans in for it to work. but I'm not all that knowledgeable  on the older bikes.

Cleaning out parts I'll never have use for.

 

 

http://www.ebay.com/itm/251608794811?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1586.l2649

 

http://www.ebay.com/itm/251608804131?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1586.l2649

 

http://www.ebay.com/itm/251608811982?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1586.l2649

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