Bench shifting new bottom end. No neutral?


6 replies to this topic
  • nitronaf

Posted July 31, 2009 - 07:50 PM

#1

Hi guys i just rebuild my bottom end and replaced some gears (it sheared a 5th gear pinion and locked the rear wheel).
Bike is a WR450 06
Put the cases back together with shift paws/rod/drum etc and installed all of the clutch components to test my transmission WITHOUT oil.
Was all smooth no hammering or forcing.
When i go through the gears all seems fine i can shift 1 through to 5th however i cannot get it to select neutral. :thumbsup:
I can hear the shift forks moving and there is no real binding other than the awkward spots of the shiftcam
The shift drum will go onto the highspot it has for neutral but the countershaft will still drive the crank??

So I've re-split the cases today to inspect if i had gotten something wrong.
Checked that the shift drum was seated properly into the shiftcam
Double checked the order of all the gears. Inspected if the shift forks were still in their tracks of the shift cam or in the wrong position.

All is fine and in working order?!?!


Do you think im just paranoid and it wont go into neutral without oil??


edit: i found a new problem. It seems in ever gear i cannot turn either the counter shaft or the into shaft more than 360 degrees.


Any help appreciated. :ride::worthy:

  • William1

Posted August 01, 2009 - 03:07 AM

#2

Re-test with the clutch basket removed. Ensure you are in first, try turn the input shaft (what the clutch rides on). Keep an eye on the shifter drum and detent. Keep twisting the input shaft. Try a partial 1>2 shift, you should hit neutral. Try second. If none of these work and you cannot spin the shaft, either a gear s on a shaft backewards, a shim or circlip is missing.

  • nitronaf

Posted August 01, 2009 - 06:52 PM

#3

Re-test with the clutch basket removed. Ensure you are in first, try turn the input shaft (what the clutch rides on). Keep an eye on the shifter drum and detent. Keep twisting the input shaft. Try a partial 1>2 shift, you should hit neutral. Try second. If none of these work and you cannot spin the shaft, either a gear s on a shaft backewards, a shim or circlip is missing.

I checked the partial shift. Its pretty easy cuz the shift drum has a little highspot for neutral. It will go onto this spot but the tranny still moves completely and then locks after 360 degress. It almost feels like 2 gears are trying to engage at the same time but thats just speculation.

I pulled it down again to check the circlips and gears. Realistically you'd have to be pretty "special" to get the gears in backwards they really only go in one way or the circlip wont go on or the gears wont mesh.
Im starting the think there is something wrong with the shifting forks or shift cam. Sigh what a hassle.

Like maybe when the transmission locked it evenly bent a shift fork. (Most likely shift fork "R") and i simply cannot tell because of the lack of info in the manual.


Or it could be im just a paranoid fool and the transmission needs to be full of oil to work (i squirted about 100ml in through the cylinder face @ the tranny but didnt really help) Do you know if it should be possible to bench shift WITHOUT oil??

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  • William1

Posted August 02, 2009 - 04:02 AM

#4

Yes, the lack of oil will make no difference. A shim in the wrong place, breaing net set in the case correctly all can do this as well as a bent fork.
With the trans installed in one case, it should be set to be in neutral. Confirm the shift drum looks correctly positioned too. With it in one case, you can view the gears as you carefully turn the input shaft.

  • grayracer513

Posted August 02, 2009 - 09:44 AM

#5

Something that has not been mentioned yet is the possibility that one or both shafts may have been bent when the trans locked. As robust as they are, it seems unlikely, but we do have an odd problem here, so it's wise to check everything.

  • ncampion

Posted August 02, 2009 - 03:00 PM

#6

You can run through the gears without having the cases together. If you actually have a gearset engaged when the shift drum is in "neutral" you should be able to see which set is engaged and figure out why. It is also possible that something is binding (bent shaft or tight gear on the shaft) and you don't actually have any gears engaged. Be sure to check the placement of all items (gears, shims etc) on the shafts as compared to the manual. Any small mistake will be a big mistake later.

  • nitronaf

Posted August 02, 2009 - 06:37 PM

#7

I've Found the problem
I took it to an expert and we went through the whole thing.
After an hour i told him i noticed there was a bit of blacking on the centre of one of the gears and it didnt turn( on the countershaft).
So i asked him is this gear supposed to turn??

Turns out that gear is supposed to be free and it took 20 tonnes of pressure to press it off.

It basically welded itself to the shaft.

Thanx for all the help guys :worthy:

Gah i feel like such a fool for not noticing it :thumbsup:




 
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