Wanted - overdrive 5th gear not fitting/searching for late trans

Motorbreath22

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Hey guys, I am upgrading my transmission with the overdrive
5th gear. My motor is a 78' with some 82' parts. I had
problems with popping out of 2nd and 5th so I bought a whole trans
that I thought to be the late model transmission.*




Went to put the 5th gear on and it doesn't fit. Grabbed my
calipers and here are the measurements:


New 5th gear inner diameter: 0.978"/24.84mm



Original 5th gear inner diameter: 0.984"/25.0mm



Transmission shaft outter diameter: 0.983"/24.95mm


I know there are supposed to be indicator grooves on the gears but are the transmission shafts different O.D.'s? *


If someone has a 80' trans or later to measure I would appreciate it. And if you have one you don't need even better.


I'll try to get some pics of the trans up.


Thanks in advanced.
 
I have the same problem with my '80 trans and Mike's 5th gear OD. My dimentions are the same as yours. Seems the maker for this gear is making the hole too small. I've read of this problem recently here.
 
There's a Yamaha service bulletin out there, somewhere, that describes the switchover of the transmission gearsets, oldstyle vs newstyle with the indicator notches. IIRC, one style has the gears designed to slide on the OD of the shaft, the other designed to slide on the ID of the shaft, neither set interchangeable. Who has that service bulletin?
 
Thanks for the input guys.

I have seen that service bulletin around as well, it is still a little confusing. From the information I had I was pretty sure I had the late model transmission
Sounds like it might be bad machining on the gear...makesme concerned about quality of their tooth measurements.
 
...makesme concerned about quality of their tooth measurements.

Drives me nuts. You find all sorts of info over the years on the 'net, then, just when you need it, you can't find it. I recall an article about XS gear tooth geometry changes, possibly for that 5th, where the involute curve was changed to allow for the extra tooth. I suppose that if your new 5th was mis-machined, you would hear a whine, and find extra iron powder on the drain plug magnet...
 
I have a 81 transmission for sell.
Shoot me some pictures of what you need measured at 3one7-six97-seven560.
 

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There's a Yamaha service bulletin out there, somewhere, that describes the switchover of the transmission gearsets, oldstyle vs newstyle with the indicator notches. IIRC, one style has the gears designed to slide on the OD of the shaft, the other designed to slide on the ID of the shaft, neither set interchangeable. Who has that service bulletin?

I think the service bulletins are on here :thumbsup:
http://thexscafedotcom.wordpress.com/tag/xs650se/

oops!...... didn't see that you got there hours ago Brian sorry
 
Thanx, guys, that's the one. Too bad it doesn't mention diameters. Found this 4-page service bulletin about transmission gear spacing (old models, but may be helpful), and started thinking about AaronKelly's 5th gear jump-out. Probably worth going over while doing 5th upgrade:
 

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It's not the trans, mikes 5th od gears are shit - simple.
I have one here with the same issues and others have reported the same if you do a search.

I havnt taken it up with Mike's, recently I had to deal with them over some other incorrectly supplied parts - I'd rather have root canal....

My last order included incorrectly supplied parts, 5th od gear that doesn't fit and a front chain guide you can drive your thumb nail through the guide material...they won't be getting anymore of my $.

If you are using some of their parts be carefull....I just placed a big order with twins- inn (Germany), all parts supplied correctly, great service, good quality and postage was 5 times less than getting stuff out of the U.S..

Good luck., my 5th od is now a paperweight & for me a timely reminder.
 
I took my Mike's OD 5th gear to a machine shop with the original 5th gear and asked them to make the new gear's shaft hole match the old gear's ID. I did try to hone it out with a brake cylinder hone but it was taking too long and I'm not sure if the hole was straight. Sometimes you gotta let the pros do it. I also agree it's a shame Mikes QC has let this pass.
 
I think the service bulletins are on here :thumbsup:
http://thexscafedotcom.wordpress.com/tag/xs650se/

oops!...... didn't see that you got there hours ago Brian sorr
I know this an old post but still very relevant in the world of 650s. The change that was made to the splines or the gears I am not sure I am understanding from the diagram.
I have a busted 5th gear and selector fork. Not sure why yet but looking at the splines on a couple XS650 transmissions, one spline has the inner diameter polished and the other has the outer diameter polished. Should the gear inner surfaces also be polished to match the particular polished surface of the spline. The reason I am asking is because when I purchased this bike things were changed and I am now guessing the gears were interchanged and if they were was it done properly, as I understand gears are not interchangeable from a 78 year to a 75 year.
I’d also like to know about the grooves cut in the gear teeth. Is there a single or double groove in 5th gear teeth for a 75 year and what about in a 78 year. I see on my 75 year there are some gears with 2 grooves and some with a single groove on the teeth. Should all the gear teeth for the 75 have a single groove cut in. I read some saying ahhhh it doesn’t matter mine works and others saying they dont mix. Really confusing.
when I built my first bike I bought a motor off eBay, never tested it, built the frame around the motor spent lots of hard earned bucks and put the motor in hooked it all up and ran it. Thats 6 years ago and I have not touched a thing on that motor except clutch plates. This XS650 motor is just discouraging the crap out of me. I think someone did a Frankenstein job and couldn’t get it to work so here I am. I’ve restored everything on this bike now and it looks a shit load better except the motor. I dont want to put it back together with a shitty transmission even though it is the weakest link in the chain.
 
I see on my 75 year there are some gears with 2 grooves and some with a single groove on the teeth. Should all the gear teeth for the 75 have a single groove cut in.
The gear/shaft/spline change occurred mid-year '77. The earlier set had a mix of grooves "ID Marks" (none & 1), the later a mix of 1 mark and 2 marks - see attached
18878-1405855539-f74350739da02fa81cefbc016b33db26.jpg

18879-1405855539-63c0a23f06a6c684dc2d3e035a675bf8.jpg

GlennTrans5th.jpg
 
The gear/shaft/spline change occurred mid-year '77. The earlier set had a mix of grooves "ID Marks" (none & 1), the later a mix of 1 mark and 2 marks - see attached
View attachment 235750
View attachment 235751
View attachment 235752
Thank you! So from what I see here the presumed 75 transmission I have is really not a 75 at all. I'll have to go through every gear on those splines. Where those arrows are is exactly where the gear is busted. Half of my it right down to the spline is completely gone. A lots of metal bits all over. Hugh has my crank and cam. I've got a 750 kit and a bunch of other new stuff to hopefully make it a little more fun. I'll let you know how the transmission thing goes. Thanks again
 
Yep, you've got a lot invested there; maybe another transmission set (all of it) is warranted.

Perhaps post a new wanted ad (this one is 10 yrs old) here in classified - just to see what's out there..
 
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