Transmission assembly question.

sherwin

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I'm rebuilding my engine and have the bottom end opened up. Everything looks good so I'm ready to put it back together.

Looking at the shifting forks and the transmission gears, how do I tell if I have them lined up correctly? Do I just slide the gears around until they fit into the forks? I have both the Clymers and Haynes manuals and don't see this specified.

Thank you,
Sherwin
 
- ensure crankshaft bearings are properly seated or the cases wont close
- make sure the shift fork shaft is absolutely clean and lubricated
- check the shift forks and matching gears for signs of wear - when, replace ... 3rd pinion, 4th gear, 5th gear
- check shift fork operation by rotating the shift drum - the shift cam should turn freely and the forks should follow ... control the cam grooves and cam followers and make sure the split pins arent in the way
- set the shift cam in neutral position...the neutral detent will tell you when
- check the gearbox shafts - all gears must rotate freely, those gears that shift laterally must do so without effort...do they engage properly - check the dogs and their receivers for wear
- look for pitting in the gear faces
- fit - the locating ring on the main shaft bearing has to locate properly
- the locating ring on the drive axle bearing is only a half ring and needs to be positioned so it locates in both case halves
- rotate the shift drum by hand, checking the lateral movement of the shift forks and the way they fit into the relevant gears
- the collar that fits inside the seal behind the front sprocket and the bearing has to be clean and mark-free
- if there have been problems finding neutral, or gears jumping out, replace the 3 springs-2 for the shift drum and 1 from the neutral detent

- its been a while since ive had my hands in a gearbox so ive probably forgotten something important
 
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Inxs, it looks like you've remembered quite a bit. Just looked in the tech section and I didn't find any specific info on transmission re-assembly. Might this thread be considered for inclusion there?
 
Thanks for the information inxs, makes it seem a little less daunting.

Without the gears/shafts in place, the shifter forks slide as they are supposed too.

With the shift forks in neutral I installed the gears/shafts. The problem comes when I try to shift through the gears they tend to lock up in spots, some gears rotate smoothly while others grind a bit then slide into place, like the engagement dogs are not engaging consistently as I shift through the gears. It seems the gears that corespond to the engagement dogs do not always line up, so they are not engaging.

I know the gears/shafts are assembled properly because I never disassembled them, I just removed the shafts from the cases, cleaned and inspected them, and found no obvious signs of wear. With the shift forks, I never removed them from the upper case or took them apart, just inspected them and saw no obvious signs of wear.

Any ideas on what the problem is? This is the only thing keeping me from getting the cases put back together (other than the fact that I need to order the seals).

Thanks,
Sherwin
 
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- are the shafts lubricated and the gears themselves rotating and sliding freely
- did you check the dogs themselves, these are known to break out, yours may be in the deformation phase
- bent and-or worn shift forks are a common problem as is wear in the corresponding grooves in 3rd pinion, 4th and 5th gears
- is there any pitting in the faces of the gears
 
The shafts, gears are well lubricated, the gears rotate and slide freely.

There is no pitting or signs of wear to the gears, engagement dogs, shift forks.

Everything seems good, it's just that when I shift, the engagement dogs on the gears don't always line up with the engagement slot on the coresponding gear. For example; the engagement dog may be at 1:00 and the slot it needs to slide into on the other gear is at 1:15. I have to rotate the shafts/gears until both the engagement dog and the slot are at 1:00. There is no specific gear (1, 2, 3, etc) that does this, it is completely random, sometimes it will shift from 1-3 then get caught up shifting to 4, or shift fine from 2-5 but get caught up shifting from 2 to 1 and so on,

It doesn't seem to be a problem with springs, shift forks, or wear to any of the parts, it's just how the individual gears on the same shaft line up to eachother. I hope this makes sense, it's driving me nuts.:banghead:

Thanks again inxs for your help with this, I appreciate it.
 
The gears need to turning to shift right. With the tranny in place and the front sprocket on, spin the sprocket to turn the shafts and gears. It should shift through the gears .
 
XSLeo,

Thanks, I've been shifting, then turning, not doing both at the same time. I'll get an extra set of hands and try it out when I get home from work.

Never occured to me to shift while they were in motion, hopefully that's all the problem is :doh: .
 
So, this is most likely stupid, but I'm gonna ask anyways. Do I need to pull the motor to check and or fix the shifting issue. It jumps from second to first. I am thinking it is a shifting fork issue. Am I correct? If not what then. Still, either way would I have to pull the motor and tear the lower end out?
 
Am I correct? If not what then.

There's a cam and lever arrangement with a spring attached that's accessible when you take the right side cover off. If the spring is broken or the lever isn't centered it can cause problems like jumping gears. Do a search on 'shifting' and 'spring' together.
 
There's a cam and lever arrangement with spring attached that's accessible when you take the right side cover off. If the spring is broken or the lever isn't centered it can cause problems like jumping gears. Do a search on 'shifting' and 'spring' together.

Anyone know where the best place to purchase all of these springs would be? I have one broken for sure as you can see in the picture, but I'll be doing a rebuild myself, and I'd think it would be best to just replace all of them while in there...
Thanks in advance...
 

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RCGT, I think if you take those two springs to your hardware store and look through the springs you will find some that match or are very close to the same and should work just fine.
gonht1, If you look in RCGT's pics you will see the shift shaft and how it mates to the shift drum.
In the first pic even with the broken spring you can see the arm that is under the drum, it has two apposing hooks, see how they are centered under the drum? Thats how they look if prtoperly adjusted. The second pic shows the adjuster There is a circular spring around the shaft and the two ends are on each side of what looks like a flat bladed screwdriver slot. That's the adjuster. There is a lock nut holding the screw in place.
To adjust you loosen the lock nut, turn the screw while watching the hooks. When centered they are good.
The nut is very tight, the screw turns hard.
If this adjustment doesn't help you need to pull the engine, turn it upside down, split the cases to get to the tranny. Often popping out of gear is either worn or bent shift forks, or worn dogs and their engagement slots in the adjoining gears.
The dogs and slots if done carefully can be reshaped. Shift forks not so much.
There are tranny parts all over Ebay.
Best to get one complete, both shafts with gears installed. 78 and up makes using Mike's overdrive 5th gear easier.
Leo
 
RCGT, I think if you take those two springs to your hardware store and look through the springs you will find some that match or are very close to the same and should work just fine.
gonht1, If you look in RCGT's pics you will see the shift shaft and how it mates to the shift drum.
In the first pic even with the broken spring you can see the arm that is under the drum, it has two apposing hooks, see how they are centered under the drum? Thats how they look if prtoperly adjusted. The second pic shows the adjuster There is a circular spring around the shaft and the two ends are on each side of what looks like a flat bladed screwdriver slot. That's the adjuster. There is a lock nut holding the screw in place.
To adjust you loosen the lock nut, turn the screw while watching the hooks. When centered they are good.
The nut is very tight, the screw turns hard.
If this adjustment doesn't help you need to pull the engine, turn it upside down, split the cases to get to the tranny. Often popping out of gear is either worn or bent shift forks, or worn dogs and their engagement slots in the adjoining gears.
The dogs and slots if done carefully can be reshaped. Shift forks not so much.
There are tranny parts all over Ebay.
Best to get one complete, both shafts with gears installed. 78 and up makes using Mike's overdrive 5th gear easier.
Leo
XSLEO, thank you so much for the intel. That is super helpful. Know just like everyone else I need to get time to do it.
 
Thank you all, for the great info. I hope this will work. Sorry to just give XSLEO the props. Great info all around. First time on a forum. Old school I guess.
 
RCGT, I think if you take those two springs to your hardware store and look through the springs you will find some that match or are very close to the same and should work just fine.
gonht1, If you look in RCGT's pics you will see the shift shaft and how it mates to the shift drum.
In the first pic even with the broken spring you can see the arm that is under the drum, it has two apposing hooks, see how they are centered under the drum? Thats how they look if prtoperly adjusted. The second pic shows the adjuster There is a circular spring around the shaft and the two ends are on each side of what looks like a flat bladed screwdriver slot. That's the adjuster. There is a lock nut holding the screw in place.
To adjust you loosen the lock nut, turn the screw while watching the hooks. When centered they are good.
The nut is very tight, the screw turns hard.
If this adjustment doesn't help you need to pull the engine, turn it upside down, split the cases to get to the tranny. Often popping out of gear is either worn or bent shift forks, or worn dogs and their engagement slots in the adjoining gears.
The dogs and slots if done carefully can be reshaped. Shift forks not so much.
There are tranny parts all over Ebay.
Best to get one complete, both shafts with gears installed. 78 and up makes using Mike's overdrive 5th gear easier.
Leo

Wow, thanks man, that was an excellent explanation for those pictures. So it looks like mine is adjusted fairly well as it sits (centered). I'll try the local hardware stores for the springs that aren't broken, problem with the one is I have NO idea what the other end of it looked like, how long it was ect...
Any ideas where I can get this info, or the name of this spring / components it's attached to?
 
Yes, I wouldn't mess with adjusting it. Your broken one is just missing the loop on the end. Which is the same as the other end.
Leo
 
Cool, that shouldn't be too hard to find, I could probably just take some general dimensions of it and order it.
Thanks again!
 
A parts seller like boats.net will have parts listings with a pic of the break down showing the parts and a list of the names.
Most repair manuals tell the part names while describing repair procedures. You do have a repair manual? If not you should get one. biker.net has them to download. Ebay often has the factory books, Clymer's, Haynes. Any are better than nothing.
Leo
 
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