Gearbox Strip Tips Or Advice

[Thumper]

After almost two years of nasty noises and 1st gear slipping whenever I took off hard from a standing start I finally lost the use of 1st gear altogether about 4 weeks ago. Every other gear seems fine so I'm just going to have to strip the gearbox(transmission) to find out what's up and replace what needs replacing. I plan to split the bottom end of the engine without splitting the cylinder-head, barrels etc. Any tips or advice are very welcome as to whether this method is a big no no or any other problems encountered by any of you guys performing this task. Thanks

[DEmily]

I recently pulled the motor without seperating the topend. Was no big deal. I found it best to remove the starter, Carbs, middle gear box and oil filter first. Leaving the front upper engine mount bolt in I lifted the back up enough to slide the back engine mount bolt back in. Then let the engine down to rest on that back bolt. Jacked up the front of the engine, after pulling the top front engine mount bolt, enought to slide the bolt back in again and the front rested perfectly on that bolt. This allowed me to slide the engine out the side with good clearence. Putting it back in the reverse order and it went real easy.

[TopCatGr58]

Hey there Thumper,

It just so happens, that the tech tip that I created and had gotten lost has recently been reprinted in the Repairs section, take a look at this:
1st and 2nd gear Tranny fix!

I was not the first, as you can see if you browse the Tech Tips, Repairs, Tranny section, Mr. Ken Talbot provided many links and lots of info for me to do mine, and I just did a blow by blow borrowing from his/links advice and my experiences. HTH.
T.C.

[mitch]

Upside down

TC you know what im gonna tell him . Drain the fluids take out the battery, remove the mirrors. Get a couple friends and turn the bike over thats how i did mine it was perfect . A lot less work and the tranny was at waist height, just right to work on, the gears just fell into place. Why spend 4 to 5 hours removing and replacing the motor when theres no need .................MITCH

[Thumper]

I'm a bit to tired and busy to read all of that link just right now but please tell me slowly and clearly if I am right. CAN I REMOVE THAT PARTICULAR GEARSHAFT WITHOUT REMOVING THE ENGINE AND MORE IMPORTANLY WITHOUT SPLITTING THE CRANKCASES??????

[xssiveone]

Originally posted by Thumper
I'm a bit to tired and busy to read all of that link just right now but please tell me slowly and clearly if I am right. CAN I REMOVE THAT PARTICULAR GEARSHAFT WITHOUT REMOVING THE ENGINE AND MORE IMPORTANLY WITHOUT SPLITTING THE CRANKCASES??????

THE ANSWER TO THAT IS "MAYBE"

It all depends upon which gears are broken. The shift forks can be removed with the engine in-frame, and one of the transmission shafts can also be removed without splitting the cases of removing the engine. Remove the oil pan, and determine which gears/shift forks are broken/bent.

[mitch]

Chit yes

I already told you. You dont need to remove the motor i did mine and Ed Condly did his . We turned the bikes up side down but you do need to read the tip several times before you start idid and even printed it out for reference as i did the tranny.......MITCH

[mitch]

Tranny

I did first and second and 3 shifting forks in mine. Just take the side covers and clutch assembly off and the tranny pan. Volia its really eazyer than i thought it would be !!!!.....MITCH

[Thumper]

Thanks a lot, I think it's the dogs on fourth gear that engage with first that are broken/damaged so I should be able to repair it using the link page. Thanks again.

[TopCatGr58]

Hey there Thumper,

When I did mine several years ago, I just used the Dremmel, however, if you can find a machine shop, or have a friend with machine shop tools, they should have the right strong, yet small metal cutting bits used on their lathes/CNC machines and the ability to set the grinds for an exact few degrees undercut and depth on both surfaces.

However, don't fret, if Dremmel is all you have, it will work! Depending on how rounded they dogs are, you might actually find it faster to use a cut off disc to remove about 1mm of thickness off the the mating/contact face. The remaining amount of dog is still plenty strong enough to hold, Yamaha overengineered these things, remember! Good luck, take your time and you'll get it done!!
T.C.

[Thumper]

I will get round to reading the dremmel fix, but i expect I will just spend the hard cash and if possible replace damaged part/s with brand new genuine Yamaha parts.
P.S. I know this will be expensive, I've heard rumours of £100 for a gear wheel. Alternatively there is a gear company nearby to my home but I expect their time will cost the same as new parts.