Need to replace 3rd gear (Transmission)

Well....third gear just went out on my 2000 WR400 (YZ timing) and I was going to crack the case and dig in to get it fixed this week.

My question....while I have the engine out and apart is there anything I should replace since it will be in pieces? New piston, rings, 2nd or 4th gear etc...???? I'll make sure to inspect and replace anything that looks shady but just want to make sure I don't miss anything!

Any other advice before I crack it open would be greatly appreciated!


Keywords: transmission, crankcase, 3rd gear, thrid gear

If 3d is gone then I guarantee that 5th is gone also since they have to mesh together for 3d to work.

BIG BORE KIT!!!! :thumbsup:

I've been thinking about that one!

iv just done this job last month if 3rd has gone then 5th needs replacing allso, parts you will need is full gasket kit, 3rd gear,5th gear, 3rd pinion, 5th pinion and make sure you chheck the selector forks for wear,

bear in mind i waited 2 months for 3rd gear to arrive as it was on back order from factory so check on this with your dealer also let them know that there is a new modifyed 3rd gear out now last part numbers was 00-00 modifyed end numbers are 10-00

5BF-17251-00-00 GEAR, 5TH WHEEL (21T)

5TJ-17231-10-00 GEAR, 3RD WHEEL (21T) changed from 00-00 to 10-00

5TJ-17151-00-00 GEAR, 5TH PINION (25T)

5TJ-17131-00-00 GEAR, 3RD PINION (16T)

if you do a search on 5th gear there is some pics i posted :thumbsup:

Your gonna need lots of parts. Price them out first before you buy! You might be able to buy another bike and save money. You did not say if the top end was ever done, after 7 years its done! Add it up, then take the money and get a new or newer bike. I know its harsh but it will save you money.

Be sure and replace the cam chain and guides.

Any wear on the shifter forks is too much.

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