BAM! There goes my second gear..

[bazwell]

Baz, have you done your gearbox yourself then? And what parts did you replace? Did you just fix the 2nd gear prob, or do any undercutting as well?

I got Yamaha's 2nd gear fix kit and a set of bearings. The kit has 4 gears and a shim.

 

[satariel666]

I got Yamaha's 2nd gear fix kit and a set of bearings. The kit has 4 gears and a shim.

Bearings does not need to be replaced. Since they are oil lubricatec under
pressure the lifespan could be extremly high.

Also in most cases only 2 gears needs to be replaced. I personaly
replace only one since second is reconditioned and works better then OEM.

 

[naughtyG]

I'm copping out the same way, G. I bought a used motor with MUCH lower milage than mine and am prepping it for installation. I'll tackle my motor down the road at my leisure. At least that's the plan. Stay tuned for the outcome...........

Well I'll be all ears!

What you need is the JediMatic (TM) instant gearbox fixer,

Yea Steve, I think I need to order 10.. BTW, do you do gear undercutting work?

That's funny Jedi!

Once out you will flip the engine on it's top (with a big catch pan under it). Remove all the covers, waterpump, clutch basket and misc, slave cylinder, oil pan/pump, then all the case half bolts. I need to do a more detailed notes but you get the idea. It's not hard at all. The hard part is cleaning up all the old gasket material.

That sounds very doable to me. A few questions:
- what do you rest the motor on once flipped? Wood blocks, or do you have some kind of custom stand I should think about?
- cleaning old gasket sounds fun - been there, done that. Question is, what gasket(s) do I need to get prior to doing the job?

Swapping the engines is easy with you only needing to swap the flywheels and pickup (or complete stator cover) over. It it's a newer engine (96+) into an older frame (95-), then you also need to get a different cross brace to clear the spin on oil filter.

I don't think I'll be swapping engines. I'm quite happy riding the '86 while the '00 motor's in pieces, and I don't fancy the hassle of pulling and refitting 2 motors when I can just do one!

I got Yamaha's 2nd gear fix kit and a set of bearings. The kit has 4 gears and a shim.

Where did you get that Baz? Here in Perth, or from abroad? How much? Did it include any gaskets?

Also in most cases only 2 gears needs to be replaced. I personally
replace only one since second is reconditioned and works better then OEM.

So you're saying only the 2nd gear gets replaced? I was under the impression 2nd and 5th where one thing, is that wrong?

Thanks to all so far for all the input! :worthy:

 

[satariel666]

The problematic gear works for 2nd and 5th. The next engaging gear(single)
with female dogs is most problematic due the incorrect profile of the dogs.

 

[naughtyG]

The problematic gear works for 2nd and 5th. The next engaging gear(single)
with female dogs is most problematic due the incorrect profile of the dogs.

Sorry to be so thick but I'm still confused :ummm:

2nd and 5th are two gears, right? As in two separate toothed wheels? Or is it one single piece that contains both gears?

And, are the worn dogs the male parts, the female parts, or both?

I really need to take a bloody gearbox apart to sort this out in my head... :bang head:

 

[one2dmax]

You need 2nd and 5th at a minimum. The 2 engage into each other. One has dogs and one has slots. Damage to one will damage the other.

You can either make a stand or what I do if it's an engine we are not painting later is set a some sacrificial foam down on the large baking pan and then just let the valve covers/engine top just sit right on it.

Sean

 

[satariel666]

Usualy I encourage you in any matter master Joda but this time I shall interfere.
You do not need to change both - I dare to say in 70% of cases 2nd gear wheel is still reusabe of course after proper machining. My findings are you can even shave them twice - a solid conclusion after messuring the hardness and its deepness.


G...ce n'est pas la fin absolute du monde
Take a look at the fiche. Two problematic gears are marked with numbers 13 and 14.
You need no. 13 for sure no matter what you will hear. There are bascialy three problems with these gears:
-axial play of no 13
-gear dog pocket/slot profile in no. 14
-axial spacing of no. 14

By buying only the new parts you will only delay the problem which will return
after couple ten tousends kilometers. After some smart modofications you can
improve the life span over 50%.

 

[Ost85vmax]

Not to hijack this but one quick question. What can I guy do to prevent/ delay second gear issues?

 

[bazwell]

Not to hijack this but one quick question. What can I guy do to prevent/ delay second gear issues?

You can get a bike with less horsepower, or ride like an old lady, or always skip second gear! :rofl_200:

Really, what you have to do is to limit your power shifts, use the clutch, and do nice solid gear changes. But if you like riding your bike, it'll happen eventually. Power shifts are the biggest wear factor IMO.

 

[bazwell]

Bearings does not need to be replaced. Since they are oil lubricatec under
pressure the lifespan could be extremly high.

Also in most cases only 2 gears needs to be replaced. I personaly
replace only one since second is reconditioned and works better then OEM.

There is truth in what Prez says. I've done it on a Katana. No bearings, no gaskets, no gears. Just machined the dogs (undercut) and put it back together. It the sort of risk I would take when I was younger. unk:
But now... I think undercutting is still good because the dogs should be a bit stronger due to work hardening. But, it has to be done by a pro, because if the dogs aren't all machined the same, you will end up with just one dog instead of three doing all the work.

If you change the gears(s), the gears you get from Yamaha are a newer design. For the clearances to be right you need to replace 2nd and 5th gear on each shaft, which is 4 gears. Make sure you close up the end play with the shims they sell. Makes it last longer.

On mine, a couple of bearings were a bit ****, so I just replaced the whole lot for piece of mind.

G, I was lucky enough to get one of Yamaha's kits NOS off ebay, but the normal way to get them is via Yamaha. (ie. Not from Australia :rofl_200


- Minumum is to machine the 2nd gears. You can do this entirely yourself, (I've done it successfully, because I had to at the time), but it's a big risk and I wouldn't recommend it.
- Better to change them for new ones. Not much risk and they work fine. It's stock again.
- Best is get everything from Sean, so full undercut (nicer feeling gear shifts) and overdrive. It costs more, but it's worth the money according to customer feedback. Ignoring money, logic says this is the best way. Better than stock.

There is three shovels, take your pick. :rofl_200:

 

[naughtyG]

You need 2nd and 5th at a minimum. The 2 engage into each other. One has dogs and one has slots. Damage to one will damage the other.

So is that something I buy from you, already undercut and ready to fit?

You can either make a stand or what I do if it's an engine we are not painting later is set a some sacrificial foam down on the large baking pan and then just let the valve covers/engine top just sit right on it.

Sean

Do you have any picture of either to set me on the right track?

But now... I think undercutting is still good because the dogs should be a bit stronger due to work hardening. But, it has to be done by a pro, because if the dogs aren't all machined the same, you will end up with just one dog instead of three doing all the work.

Did you do undercutting? If so, who did it for you?

If you change the gears(s), the gears you get from Yamaha are a newer design. For the clearances to be right you need to replace 2nd and 5th gear on each shaft, which is 4 gears. Make sure you close up the end play with the shims they sell. Makes it last longer.

Did your kit include the shims?

On mine, a couple of bearings were a bit ****, so I just replaced the whole lot for piece of mind.

I guess I'll have a look at mine once open then decide. I won't be in much of a rush since I'll have another bike to ride..

G, I was lucky enough to get one of Yamaha's kits NOS off ebay, but the normal way to get them is via Yamaha. (ie. Not from Australia :rofl_200

Yea I figured that much... It'll be coming from the US for me for sure..

 

[one2dmax]

Just need to email me and i'll get you pricing. we can either do the work on an exchange or do the work on your core. I suggest to fully undercut the trans (either stock gearing or with the optional overdrive). We can undercut and replace just those gears if that's all you want to do but you won't really save all that much in the long run.

 

[bazwell]

No undercut gears for me, mine has just got the new gears from Yamaha. They are slightly undercut from the factory, but not as good as they could be. When I fixed 2nd on my Katana I machined them myself. I was probably lucky to get it right.
If you are fishing for someone to try in Perth, try calling Australian Differential & Transmission Services

The yamaha gear kit comes with 4 gears and 1 shim. You can buy the shims on their own from Yamaha. My ebay kit was missing the shim, but Sean sent me one.

 

[jwood462]

How much should the dogs on the gears should be undercut to be effective and leave as much metal on them as possible. I know they are on a taper what is the maximum at the bottom of them.

 

[davesax36]

The most important part of the undercut is that all the dogs touch at the same time. The tolerances from the factory are such that you are waiting for rounded surfaces to wear down so they match. The undercut process gives you flat matched surfaces that make consistent contact from the start.

Sent from my Galaxy Nexus using Tapatalk

 

[Fastatv]

I had the same problem....was very discouraging. I purchased all the gears, bearings, gaskets, and shifting forks from Sean. My thought was to change it all, one time, have confidence in the trans, and be done with it. Some may disagree, but I thought it was a big JOB...many hours of labor, especially the cleaning and removal of old gaskets. Rick

 

[PATMAX]

If I had a tranny go bad, the labor is so intensive for me personally that I would ship the whole paperweight to Sean for a full rebuild, rings, honed, ported, HD oiler, possibly the OD 5th.
Cracking the cases does not make sense to me if just for a 2nd gear fix. I'm not gonna say its the same amount of work but a gasket set is going to be needed, bearings and reciprocating surfaces need checked, and on and on. Pay the extra for fresh parts and probable longevity of the entire motor.
In my case, I have a set of forged pistons, rods and crank that need a new home.


When in doubt...Gas it !!!

 

[schudaddie]

You need 2nd and 5th at a minimum. The 2 engage into each other. One has dogs and one has slots. Damage to one will damage the other.

You can either make a stand or what I do if it's an engine we are not painting later is set a some sacrificial foam down on the large baking pan and then just let the valve covers/engine top just sit right on it.

Sean

planing on doing this over the winter. my question is how heavy is the engine?
can it be done alone or is it a 2 man job.
thanks in advance, bill

 

[Rusty McNeil]

Unless you super creative its a two man job.
I'm guessing mine weighed about 225-230.

I pulled mine by sitting with my legs under it and used knees and hands to lift and lower it into my lap.
Not so smart, bruised my legs just from the weight.

Took some 2x4 and made a rectangle with raised cross pieces to put it upside down on with card board stapled to it to not mar the paint on the cam covers.

Used a winch to put it back. I helped a buddy out one in with a floor jack but that defiantly takes two people, one to move/position it and one to steady the engine on the floor jack.

 

[[email protected]]

I pulled mine myself. Bike was on the centerstand. Swingarm, carbs, radiator, mid gear, etc... removed from engine first.

Put a floor jack under oil pan. I put a short piece of a 2x8 on the jack and the motor came out easily. One hand on the jack, on hand on the valve cover when moving.

Once out and in the open I was able to balance it on the jack directly under a steel beam in the garage. I had previously made an engine storage stand (not for wrenching, for transport). Wrapped staps around engine, and lifted it up with a come a long attached to the beam. Then attached it to the stand.

I DON'T recommend dead lifting the engine and stand into the bed of a truck. The consequences don't show up immediately, they kinda sneak up on you the nest day and linger awhile.

My suggestion would be to buy damons video. It will help with the rebuild and it will give you an idea on how to mod a regular engine stand to hold the max motor