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wr-426

426 engine assembly

11 posts in this topic

I finally got hold of all the parts i need to rebuild my 426. it did a selector fork and gear pinion. the cases are split and the gear shafts are rebuilt and ready to go back in.

it is all laid out on a table with clean rags underneath it and i think i will attack it this weekend. are there any things to keep an eye out for when putting this back together. what are some common mistakes made by people that i can make special effort to avoid.

any tips are much appreciated,

Cheers,

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make sure you you get a manual and just take your time. I just rebuilt my wr400 engine and it was the first time i had done a rebuild and it still works so i must have done some thing right.

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I believe the shifting forks are "pinned" onto the shafts right? If so, they are a royal pain to get installed while juggling the transmission in one hand and all three shifting forks in the other! If you use a rubber band criss-crossed to hold all of the transmission gears onto there respective shafts, if helps make the job more manageable. Then after installation, just cut the rubber band and pull out!!! Also, after you complete the installation, but before buttoning the whole thing back up, shift it thru all 5 gears to make sure it works. You'll have to be spinning the gears to get them to shift, and they will still shift poorly, but with a little coaxing they should go thru all 5 shifts, and then you can close it up. Let us know how it goes!!! Maniac

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thanks a lot fellas, some really great advice here. i'll keep an eye on this thread for anything i should keep in mind. and i'll keep you all posted on how it goes back together. my frame is being sandblasted as we speak. hopefully it will come back to the great bike it was before it all went bang

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locktite blue or red for any of the anti rotation tab hardware... pick up some quality Threebond 1194/Yamabond/Fujibond/Hondabond (same stuff) sealant. Don't use any sealant that fully cures (Permatex). Also buy new gaskets/seals from the dealer, aftermarket ones are about as useless as the bags they arrive in.

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alright , i got my gears, selector forks and drum into the cases and i can move through gears with cases apart but when i slip the cases together i can't get past 3rd gear. gears 1,2 and 3 select easily and the cases went together very smoothly and easily. i have taken it all apart and put the cases together a few times but i just can't make it select 4th or 5th. i have gone through and checked the condition of all the forks gears and the drum, all is good and moves smoothly but as soon as the cases go together no 4th or 5th.

i tried selecting 4th and 5th with the cases not bolted up and the cases want to push apart as soon as there is any pressure on the shift shaft.

pretty baffled, i have been very thorough in checking everything but i must be missing something. any help would be appreciated

Cheers,

Jesse

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alright , i got my gears, selector forks and drum into the cases and i can move through gears with cases apart but when i slip the cases together i can't get past 3rd gear. gears 1,2 and 3 select easily and the cases went together very smoothly and easily. i have taken it all apart and put the cases together a few times but i just can't make it select 4th or 5th. i have gone through and checked the condition of all the forks gears and the drum, all is good and moves smoothly but as soon as the cases go together no 4th or 5th.

i tried selecting 4th and 5th with the cases not bolted up and the cases want to push apart as soon as there is any pressure on the shift shaft.

pretty baffled, i have been very thorough in checking everything but i must be missing something. any help would be appreciated

Cheers,

Jesse

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bumping this thread back up because i am completely stuck on this, i have looked at exploded parts diagrams to try and make sure i have all washers/spacers in the right places and i can't see anything wrong, but i guess i must be doing something wrong. the cases go together very nice and easily and i can shift through gears with the cases apart but can't go past 3rd with them together, it wants to push the cases apart when i try.

really need a bit of help guys,

Cheers,

Jesse

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Hi,

I know that yamaha have made a memo about the 5th gear. A wrong washer, plate position that easily switches do the other side of the gear and prevents braking the transmission when you hit 5th gear, thing that is frequent in the yamaha bikes. Maybe that will also help you with your problem.

Cheers

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not exactly sure what you mean, could you perhaps explain a bit further, i am interested. i really want to get this thing back together

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