All That Glitters

[3Phase]

I was taking one last look inside of the transmission before putting the oil strainer cover back on the engine and buttoning up the clutch when something shiny caught my attention. What the? The oil pump was brazed!



Only the oil pump drive gear cover was brazed, not the pump itself - whew!




The transmission gears appear new; they've been replaced!

5th gear wheel dogs and 2nd gear wheel slots are like new



4th gear wheel dogs and 3rd gear wheel slots are like new (I added a hair to the photo just to make Ivan happy).
There are some metal shavings visible in the drive axle splines just below 4th gear.



For some reason I don't understand, the 5th gear wheel and 4th gear wheel are grey but the other gears are brown




So, someone at the Yamaha dealership brazed the oil pump drive gear cover instead of getting a new one. That was scary until I found out what had been brazed, although it does appear that at least some of the transmission gears have been replaced. It's been a long day and I'm almost inexplicably pleased.


Regards,

Scott

[bikerphil]

2nd gear

Hey 3phase, I'm sure you've read about the 2nd gear washer swap. IMHO, it's the way to go. I've done several tranny rebuilds on these motors with the washer swap, and 2nd gear has never let go on me ever again, like it used to without the swap. Just my $.02.

[DGXSER]

Phil,

Did you also do the machining of the dogs and slots or just the washer swap? And how bad was the slipping prior to the washer swap? Did you also add the additional washer to the original position, or just move the one back?

Thanks,
Don

[bikerphil]

DGXSER, yes, I always do my own machining of the gears. After they've gone beyond their service limit (?), I'll use a virgin set of new/used gears and machine them. To add an additional washer (1 on each side of 2nd gear), 2nd gear itself would have to be machined down to accommodate the extra washer. No, I don't do that, I just switch the washer over to the other side of 2nd and re-assemble as usual. On the question you asked regarding the slipping... Once the gear slips repeatedly, it's sharp downhill from there, they will start destroying each other. The whole idea of the washer swap is to increase the contact area of the 2nd/5th dogs and slots and never let these gears start slipping, therefore, no self destruction. In my experience, this washer swap will greatly extend the life of the 2nd/5th gear combination.

[andreashweiss]

brazing is factory stuff

I have taken many engines aprt. The brazing on the oil pump cover is factory. Something done by the factory build team. Not a repair. thanx andreas

[3Phase]

I have taken many engines aprt. The brazing on the oil pump cover is factory. Something done by the factory build team. Not a repair. thanx andreas

Thank you, Andreas! I feel much better now. The only place that ever did any work on this bike was the local Yamaha dealer as neither P.O. was mechanically or motorcyclically inclined.

Any idea why the cover is there? OSHA wasn't even ten years old in 1978 so they probably had not yet gotten around to requiring hand and finger guards on unexposed, internal gears....

DGXSER, yes, I always do my own machining of the gears. After they've gone beyond their service limit (?), I'll use a virgin set of new/used gears and machine them. To add an additional washer (1 on each side of 2nd gear), 2nd gear itself would have to be machined down to accommodate the extra washer. No, I don't do that, I just switch the washer over to the other side of 2nd and re-assemble as usual. On the question you asked regarding the slipping... Once the gear slips repeatedly, it's sharp downhill from there, they will start destroying each other. The whole idea of the washer swap is to increase the contact area of the 2nd/5th dogs and slots and never let these gears start slipping, therefore, no self destruction. In my experience, this washer swap will greatly extend the life of the 2nd/5th gear combination.

Phil, I took a third look this evening and the 2nd gear washer hasn't been swapped. Looking at the engagement pattern and depth it doesn't appear necessary at this time. I don't like gears riding against bare clips so I'll try to find a new set of gears and two washers, then have the new 2nd gear machined.

I may need to change the 1st gear wheel and the middle drive gear before too long.


5th gear wheel dog engagment depth in 2nd gear wheel slot



5th gear wheel dog engagment depth wear pattern in 2nd gear wheel slot shows approximately 4/5th of the dog engages the slot. That's not bad.



Middle drive gear slot wear from 1st gear dogs



1st gear dog wear



It looks like I've managed to mangle the new 1st gear wheel dog, it doesn't look healthy.


Regards,

Scott

[trbig]

I don't like gears riding against bare clips

I can understand your hesitancy.. but there's a ton of bikes out there running that way, and I've personally never heard of a single problem from it.

Something to maybe think about... They do make a washer that is the right size and exactly half the thickness of the washer in front of 2nd gear. Brain is a bit fuzzy right now, but I seem to remember another washer that you can swap on 1st gear also. So what I did, was move the washer on 2nd like always with it running against that clip, but on 1st gear, I removed that washer and installed two of the 1/2 thickness washers.. one on each side of first. What I have found though, is a slight noise sometimes when I'm in 4th gear. What I think is happening is that I moved 1st too close to 4th by that 1/2 washer thickness. In 4th gear, I think the dogs are still rubbing on 1st gear slightly/intermittently.

So... I don't recommend the washer swap for 1st gear.. but you could do this to 2nd gear... have a 1/2 thickness washer on each side of the gear to "Protect" that clip.

Now.. can't tell you the size of the washer anymore.. but I remember I had to buy like 25 or something when I got them. If I can find them, you're more than welcome to a couple. It isn't going to move the gear much, though it will a little.

Tod

[3Phase]

I can understand your hesitancy.. but there's a ton of bikes out there running that way, and I've personally never heard of a single problem from it.

Tod, I've never tried it on a motorcycle but I've had mixed result with other types of machinery. The main problem I've had running snaprings without washers is wear.

The ring begins to turn with the part and snapring groove wears; the ring fit becomes loose and the ring itself and the eyes wear thin and break off - usually when you try to use the snapring pliers and you have to pick out a blind snapring; sometimes under load and it'll hose up and spew.

Something to maybe think about... They do make a washer that is the right size and exactly half the thickness of the washer in front of 2nd gear.

I knew I should have measured that washer before I put the bike back together. <sigh> Oh well.

I'll see if I can find some metric shims, arbor washers, or something similar for a second 2nd gear wheel washer. If possible, I want to leave the majority of the transmission undisturbed when I replace the 1st gear wheel and the middle drive gear wheel.

Hopefully that won't be happening for a while and I have time to plan!


Regards,

Scott

[trbig]

This particular snap ring doesn't have the eyes on it and it is much stouter than most. I've had several motors apart after doing this and have never personally seen a problem or heard of one... but not saying your reasoning is faulty either. I just don't think in this case that it's a problem.

BUT.. it is your bike and your decision. You get nearly double the penetration of the dogs into the slots with this swap is why most do it. Good luck.

Tod

[Yahman]

I'll see if I can find some metric shims, arbor washers, or something similar for a second 2nd gear wheel washer. If possible, I want to leave the majority of the transmission undisturbed when I replace the 1st gear wheel and the middle drive gear wheel.

Hopefully that won't be happening for a while and I have time to plan!


Regards,

Scott

Hi Scott, I have some extra washers from when I did my transmission, as I had to order a ten pack of them. I can send you a couple of them, just pm me with your address if you want them.

Larry

[3Phase]

Held up by smog and a cheap chunk 'o bronze

CA DMV put a hold on the Toyota's registration renewal and said I had to get it smogged again. WTH? It passed with crying folors but set me back a day, then I discovered I have to wait until Friday to get a new Ford pilot bushing before heading back to Arizona.

I have another day to play - yay!

This particular snap ring doesn't have the eyes on it and it is much stouter than most. I've had several motors apart after doing this and have never personally seen a problem or heard of one... but not saying your reasoning is faulty either. I just don't think in this case that it's a problem.

BUT.. it is your bike and your decision. You get nearly double the penetration of the dogs into the slots with this swap is why most do it. Good luck.

Tod

Yes, you're right. I was describing general snap ring problems. I should have written

... and the eyes, if any, wear thin and break off ....

Anyway, the only shifting problem I've had so far on the bike is an occasional 3rd -> 4th upshift false-neutral accompanied by the 1812 Overture. I really wanted to see what those pinion dogs look like but it was not possible without further disassembly.

Even with the camera, a droplight and a large magnifying glass, what I could not see taking the pictures almost blindly from underneath the bike on the centerstand (I have become farsighted; have to remove at least one eyeball from my head and set it on the floor peering up through my glasses to see anything but blurred gears and oil) were the 4th and 2nd gear pinion dogs.

Again: the 4th and 5th gear wheels have been replaced and they appear to have the slight bevel of new-style gears. What I saw in the pictures I took showed good 2nd/5th and 3rd/4th contact patterns. I'll have to work out what adding a washer would do, as the contact marks show there is already at least 4/5ths engagement. Too much more engagement and it will drag coming out of 2nd gear.

1st/4th has a minimal contact pattern and it's tore up from the floor up. The gear wheels need to be replaced. Without disassembly I can't tell which way to shim for better contact or if it's even possible to do so without causing the gears to drag or hit one another.

As much fun as it would be to lash this bike up to the rafters or drain its vital fluids and flip it shiny-side-down for a while, I think I'll gut the bike, remove its head and split the case to replace the 1st and 4th gear wheels. While I'm in there I'll do the valves and change the cam chain, then take a look at the rest of the engine, the transmission and a metric boatload of other things.

Hi Scott, I have some extra washers from when I did my transmission, as I had to order a ten pack of them. I can send you a couple of them, just pm me with your address if you want them.

Larry

YHM