filipgranbom
XS650 Member
Do I have to remove the top and the cylinders, or can I just turn the engine upside-down and lift the bottom crankcase and get to the gearbox from there?
Sincerely,
Felle
Sincerely,
Felle
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Replacing worn out gears...
- Thread starter filipgranbom
- Start date
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- engine rebuild transmission
I see this is your first post, lets start by Welcoming you to the forum.
No you don't need to pull of the top end. You can flip the engine upside down and remove the lower case. You do have to remove both the left and right sidecovers to get to all the case nuts. There is one behind the clutch and by the starter gear cover on the left side.
Leo
No you don't need to pull of the top end. You can flip the engine upside down and remove the lower case. You do have to remove both the left and right sidecovers to get to all the case nuts. There is one behind the clutch and by the starter gear cover on the left side.
Leo
Attachments
Just had a thought, Why do you think the gears are worn? It may be just a misadjusted shift arm or broken springs on the shift arm and shift drum.
Leo
Leo
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filipgranbom
XS650 Member
Thank you!
Well, when I try to put in 1st gear, I'd say the bike acts just as if one of the gearwheels would be shattered. But I'm pretty new at this, so I can't say for certain.
Whatever the problem, I thought I have to split the engine and have a look at the gearbox - which I now know can be done without messing around with the top and cylinders and all that stuff. Thanks for that. This should get me out on the roads, hopefully, much sooner than I thought.
About your other question - I don't know. But I guess I will, once I've had it apart and had a good look.
Sincerely,
Felle
Well, when I try to put in 1st gear, I'd say the bike acts just as if one of the gearwheels would be shattered. But I'm pretty new at this, so I can't say for certain.
Whatever the problem, I thought I have to split the engine and have a look at the gearbox - which I now know can be done without messing around with the top and cylinders and all that stuff. Thanks for that. This should get me out on the roads, hopefully, much sooner than I thought.
About your other question - I don't know. But I guess I will, once I've had it apart and had a good look.
Sincerely,
Felle
All the things I mentioned can ne looked at without even pulling the engine. All that stuff is under the right side engine cover.
On adjusting the shift arm you look and see if the upper lever is spaced evenly on the shift drum. This lever has a spring to hold the lever engaged to the shift drum.
The shift drum has a roller on a lever that a spring holds against the shift drum.
If either of these springs are broken the transmission won't shift into gear and not stay in gear if it does shift.
I don't know what repair manual you have, in the Clymer book page 80 has the procedure to adjust the shift shaft. In pic 7 you can see the spring between lever 1 and lever 2. If this spring is broken the lever won't turn the shift drum. Page 92 shows the other spring part 28 it holds part 23 against the pins in the end of the shift drum.
In the Haynes book page 32 pic 13.2a shows the shift shaft. You can see both springs in that pic. Page 55 has the adjustment procedures.
If these parts are not working as they should when you try for first gear it may not shift fully into gear and just let them spin, as you say shattered.
I reccomend you check these things before you tear it apart. You may find you don't need to tear it down.
Leo
On adjusting the shift arm you look and see if the upper lever is spaced evenly on the shift drum. This lever has a spring to hold the lever engaged to the shift drum.
The shift drum has a roller on a lever that a spring holds against the shift drum.
If either of these springs are broken the transmission won't shift into gear and not stay in gear if it does shift.
I don't know what repair manual you have, in the Clymer book page 80 has the procedure to adjust the shift shaft. In pic 7 you can see the spring between lever 1 and lever 2. If this spring is broken the lever won't turn the shift drum. Page 92 shows the other spring part 28 it holds part 23 against the pins in the end of the shift drum.
In the Haynes book page 32 pic 13.2a shows the shift shaft. You can see both springs in that pic. Page 55 has the adjustment procedures.
If these parts are not working as they should when you try for first gear it may not shift fully into gear and just let them spin, as you say shattered.
I reccomend you check these things before you tear it apart. You may find you don't need to tear it down.
Leo
filipgranbom
XS650 Member
Damn, thank you. A lot. Could I outrule any of these possible faults if I am able to get into 2nd, 3rd, 4th and 5th gear?
I have the Yamaha Workshop Manual from ~70 something, which has the early bikes covered. I have neither the Haynes nor the Clymer manual, maybe I should get me one of them as well...
I have the Yamaha Workshop Manual from ~70 something, which has the early bikes covered. I have neither the Haynes nor the Clymer manual, maybe I should get me one of them as well...
filipgranbom
XS650 Member
Got my hands on a Haynes manual, and looked up the pages and pics you recomended - most helpful. Will check these things first, before splitting the engine. Do you know of any dealers that have parts for the XS1b engines? I've checked mikesxs, heiden tuning, 650 central, but they don't have much for the older engines.
Sincerely,
Felle
Sincerely,
Felle
filipgranbom
XS650 Member
Ok, so I split the crankcases just to find out... What you already told me. There doesn't seem to be any damage done to the gears, they all look fine. Was a bit suspicious with the gear forks - if I am able so get into all the gears by hand, turning the star-like washer/disc back and forth while rotating the axels; can I outrule any faults with the forks and their function?
To me, the problem must be somewhere between the gear leaver and the star-like thing, which you told me.
Please, do correct me if I am wrong.
Felle
To me, the problem must be somewhere between the gear leaver and the star-like thing, which you told me.
Please, do correct me if I am wrong.
Felle
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This would be a convenient time to install the Mikesxs 5 th gear that reduces the highway rpm's.
filipgranbom
XS650 Member
Sure is. You'd recommend that? He got those for the early models? Mine is a xs1b, I think. The one from -71. Any other upgrades you guys would recommend me to do, while I have the bottom crankcase off?
Cheers
Cheers
Mike's new gear may or may not work with your XS1B, it was designed for a 78 up tranny. The earlier gtrannys used a different engagement of the gears to the shafts. Yours may be worn enough to allow Mike's gear to fit your shafts.
In the adjustment procedures they say to have the tranny in 2nd, 3rd of 4th gear when adjusting the shift shaft. If the adjuster is more toward the high side it will less on the low side. This may make the upper shifts ok but let the lower gears not engage well.
If your 70 something Yamaha manual is like my 70-74 book page 49 has the adjustment of the shift shaft.
As I said checking this and for the other things mentioned before you split the cases may have fixed the problem.
But as you have the cases split You can inspect the gears, shift forks and drum by following the Transmission section of your repair manual. Look in the table of contents, Chapter I Crank cases, Transmission.
Leo
In the adjustment procedures they say to have the tranny in 2nd, 3rd of 4th gear when adjusting the shift shaft. If the adjuster is more toward the high side it will less on the low side. This may make the upper shifts ok but let the lower gears not engage well.
If your 70 something Yamaha manual is like my 70-74 book page 49 has the adjustment of the shift shaft.
As I said checking this and for the other things mentioned before you split the cases may have fixed the problem.
But as you have the cases split You can inspect the gears, shift forks and drum by following the Transmission section of your repair manual. Look in the table of contents, Chapter I Crank cases, Transmission.
Leo
filipgranbom
XS650 Member
All right. After closer inspection it turns out someone's been trying to run a almost complete -71 gearbox with the exception that the shift-cam/drum is from -72. And from what I can tell; what differs between the -71 and the -72 gearboxes are just the shift-cam or shift-drum, the 1st gear-wheel and the main axle.
The 1st gear-wheel from -71 has 31 teeth, while the later one has 32. It's the same with the axles, of course. Is this why the shift-drums/cams are different as well?
Do you know what differs; since the shift-forks are all the same no matter what year.
But most important, since I've got another spare-motor, can I run a complete gearbox from -72, with different 1st gear, different axle and different shift-drum assembly in my -71 crankcase, and make that work? Or will I have to get hold of a real -71 shift-drum assembly?
Sincerely,
Felle
The 1st gear-wheel from -71 has 31 teeth, while the later one has 32. It's the same with the axles, of course. Is this why the shift-drums/cams are different as well?
Do you know what differs; since the shift-forks are all the same no matter what year.
But most important, since I've got another spare-motor, can I run a complete gearbox from -72, with different 1st gear, different axle and different shift-drum assembly in my -71 crankcase, and make that work? Or will I have to get hold of a real -71 shift-drum assembly?
Sincerely,
Felle
JasperLP
XS650 XS-1B
The transmissions will swap out just fine. You'll also have to swap the gear on the kick start shaft! Found that out the hard way. I put a '77 transmission (and kick start gear) in my '71, but I used the '71 drum and forks.
