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Bike won’t shift into 4th after rebuild

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So here’s the situation I just rebuilt a 05 crf250r (new crank and main bearings) the motor runs great and so do gears 1-3 but it won’t shift into 4th or 5th. When you click it up the shifter goes up and nothing it doesn’t even feel like a gear is there. Both shift forks are in and I had no extra pieces and idea what it could be? Thanks for any and all help! 

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Unless the indexing of the shift drum pin / drum center is off (what is called the shift 'segment' on a Yamaha)

which can be checked externally from the center cases by disassembly of the RH side/clutch cover and shift assy.

as you no doubt already figured out...there's unfortunately only one sure way to find out.

 

Did you spin/shift the gears before bolting the cases back together?

 

I'm currently at this point before mating the cases of my YZ125, no kidding I must have quadruple checked

it by now just to make sure everything shifts smoothly before bolting the engine back together.

Edited by mlatour

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I didn’t spin or shift the gears before putting them back together. I just put them and bolted it back together which work on a KX65 a did earlier in the year. That very well could be it, I will have to check the bike when I get time next week. I take it that’s in the service manual how to check it?  

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Well I'm more familiar with my YZ and never having disassembled that far into my CRF250X,

I had a look thru it's service manual and unlike the YZ which has the pin machined as part of the shift drum,

the CRF design looks to be a separate pin which, if forgotten could put the 'drum center' or 'segment' out-of-time with the shift drum.

Also thinking that tightening the bolt with an impact gun would likely shear the pin.

 

The Honda CRF250X service manual has no mention of it but in the YZ125 manual it suggests upon reassembly

while everything is installed in one case half, to check the operation of the shift drum & shift forks by spinning

the main shaft by hand while cycling the shift drum into each detent.

 

As experienced on the YZ, since the other case isn't supporting/aligning the gear shafts, shift drum and shift fork shafts,

it may take a bit of wiggling/holding them until you find the sweet spot that everything lines up and it cycles smoothly thru all the gears.

 

Edited by mlatour

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Did you keep the gear shafts assembled or did they come apart ?

So it actually clicks into another gear but it acts like a false nuetral?

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The last gear or two came off but the majority of the shafts stayed together if I remember correctly it’s been a long projected. It clicks through 1-3 perfect but when you go for 4th it just lifts and you feel nothing not even a false neutral. 

Hmmm I will have to find a service manual and get to reading. 

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When I put a new crank in my 2005, I had the same issue except I couldn't shift into second gear.  I could force it in with a socket on the shift drum (when I had the side cover off) and then it would shift through 3,4,5 just fine.  Ended up tearing it back apart and found that I put one gear on backwards so it wasn't engaging correctly.  I would guess this could likely be your issue too. 

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Start by manually turning the shift drum and spinning the gear shafts to see if all the gears engage that way.

If you cant get the gears to engage properly, then something isnt right on the main or countershaft gear clusters and you will have to split the cases to assess.

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Working on getting the motor apart here’s where it stands now on the right side of the motor. I was thinking more on it and I never had the shift drum out only the shift forks and the transmission assemblies. Does anybody see anything wrong here? If not I’m going to pull the motor and check to see if the gears are installed correctly. 

B5B7538B-29CE-492A-99C5-F5531FA272E3.jpeg

2DC01B13-929F-412F-AB85-078B86DBD747.jpeg

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You may be missing the thrust washer and snap ring on the starter idler gear, see below.

I can't seem to find it on the 2005 250R parts fiches but my CRF250X service manual shows them.

(this is taking into consideration that the X engine is 95% the same as the '04-09 CRF250R)

Pull the gear off and see if there is a snap ring groove in the shaft.

 

If it's the case, IMO that could cause the countershaft to move left/right between the cases and perhaps bind up some gears.

 

05.jpg

Edited by mlatour

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I did nearly the same thing when rebuilding my CRF. I just didn’t have 1st or neutral. I’ll wager that the shift forks are not correctly timed as mentioned before. Meaning one of the forks hits the end of the groove in the drum before the others.
You will have to split the cases again and manually rotate the drum to make sure all the gears are there prior to reassembly.

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Attempt number two. There’s a washer behind the idler gear but no snap ring I believe I’ll double check tho before assembling it, thank you! Any other hints or helpful tips? 

6DDCB626-6FFF-47CD-84C2-9DA8A6B77FF5.jpeg

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On a side note, if it wasn't already part of your rebuild

since you have the cases split now would be a good time to replace the balancer shaft oil seal(s)

to prevent the dreaded CRF engine to gearbox (or vice-versa) oil migration issues.

Edited by mlatour
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Ok I got the transmission out and put it together again. Does this look right? I tried to spread the gears so everything could be seen

2898F947-A6A1-4683-885E-319A3AE983DC.jpeg

DDFFB48F-FEAA-451C-BC90-21F68F8FDAE4.jpeg

329871C9-D612-4447-A210-F3FEB407537D.jpeg

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Only thing I can see that may need double checking is that the C2 28T gear is oriented in the right direction.

Edited by mlatour

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I'd say the C2 28T is not installed in the proper orientation,

as the engagement notches look to be facing outward?

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