Help on sudden shifting trouble 81 XS650 H

[papasmurf]

I threw the master link and this resulted in a split side cover and a sheared clutch push rod. I had just installed this 81H model engine in my 78 XS650 SE frame after blowing most of the tranny last September. I am not a mechanic and missed an opportunity to discover the 'missing link' retainer when I adjusted the suddenly loose chain after over 500 miles on the replacement engine. I waited patiently for new spacer balls, push rod seals and new master link while I polished the side cover form the old 78 engine. When I got the parts, I installed the new seal and scavanged push rod and sidecover. The shifting was not anywhere near what it has been for the first 500 when it was all clean and crisp, including neutral. Now the lower gears sometimes work but it won't shift into the higher gears. I have R&R'ed the side cover a couple times looking for binding and find none. I also find that if the engine is off and I shift it manually up on the center stand, I need to turn the rear wheel quite a bit to make the changes, but all the gears are there. There also seems to be a lot of backlash while in gear - can't recall I ever made this observation before so I have nothing to go on. But wait - there's more. Under the machine when I removed the broken parts, I found this part - a circular spring - very small and I am suspicious it is related to my problem. Any ideas at all?

By the way - I am not a wrench - my career was in chemistry - I was good at that, but I probably ought to have someone throw a couple bags of sawdust on my garage floor so it can look like a butcher shop. Well - maybe not that bad, but close!

 

[sgallaty]

I did the same thing to another vintage engine years ago. Put on an old chain just "for now", and forgot about it. It ended up coming apart and the chain bunched up between the front drive sprocket and case and pushed a hole in it.

I like continuous drive chains now.

I welcome a chemist in our midst. Please if you would be so kind, comment on this thread?

 

[jamesgs4]

It sounds like you need to adjust the worm gear for the clutch pushrod. No idea where that spring came from, it is not a part of the engine cover or anything from that side of the engine.

 

[papasmurf]

not to sound too awfully dumb, but the worm gear is the clutch adjustment screw under the left side cover, correct? If so, I have adjusted it a couple times, but probably have to learn where the sweet spot is - I have gone to both extremes on it I think. At one extreme, it is wanting to slip a bit - at the other when the handle is in, there is definitely no slipping.

 

[jamesgs4]

yeah that is the adjustment. if the pushrod is even slightly bent, it can be binding.

 

[Greg]

that little spring looks like is came from the pushrod seal there is a spring where the shaft enters the seal on the inside

 

[flyboy]

Greg is right. There is a spring inside the pushrod seal and to my thinking that would make the pushrod behave differently...possibly wobble in the seal thus creating an inconsistancy on the surface it pushes against.
I would replace the pushrod seal with a new one (buy three in case you screw one up) and be sure the case is chamfered a bit to accomodate the new seal as they were originally put in from the inside of the case when new. Grease the new seal with Yamabond before you put it in.

 

[jamesgs4]

the seal only keeps oil from getting out. there is a brass bushing behind the seal that keeps the pushrod straight, if that was damaged it could also cause binding. mixesxs has a how-to section on replacing the bushing and the seal.

 

[papasmurf]

OK - that explains the spring now. We replaced the seal and having donethat before it went nominally. The old seal had to be butchered to get it out because the sheared off pushrod was just below - and bent - the surface of the seal. Once we had the seal out we used a powerful magnet to retrieve the remaining pushrod and 5/16" bearing. The replacement pushrod was scavenged from my 78 motor which had only second gear left in it - that is why I put the 81 motor in the bike this spring after all. So - I will try again adjusting the clutch with the worm gear, but I am pretty sure I had done what the manuyal and Tips sections suggest - bottom out the cable adjuster at the handle so all the cable is available and then remove the slack with the worm gear and fine tune it with the handle adjuster on the road which I have done a a couple times now. My concern is that I may damage a good transmission by some overlooked problem here. It shifted very well prior to the chain fault - now it doesn't. That is my conundrum.

 

[papasmurf]

wish my keyboard could type better - I will be more careful about those typos in the future - sorry

 

[5twins]

There are a couple small springs under the right side cover that connect to the shifter and a detent drum. They sometimes break and that can cause hard shifting or popping out of gear. This may be related to your mishap or one of them could have just decided to up and break on it's own.

 

[papasmurf]

Wow - nice pic! Is it possible that this is why my 78 motor I just replaced with the 81 no longer goes into any gear but 2nd? For probably 3,000 miles or so she wouldn't stay in first so I just didn't use it. Then last September I was getting on her pretty good and did a normal shift into third and it wasn't there. Neither was 4th or 5th. Back down I went and second was still there. That was a big WTF for me but she had the decency to give me a way to get her home without hauling her.
I have the time later on when summer cools down a bit to pull that side cover on the 78 and have a look. Thank you!

 

[5twins]

Can't hurt to look because the next step is splitting the crankcases to get to the actual tranny. MikesXS sells the little springs if you need them. There are 2 and they are different from one another (although they look similar).

 

[papasmurf]

The seal was undoubtedly the source of the little spring. There is a new seal in there now. I have a good pushrod from the 78 engine in there also - with new 5/16" bearings. I started from scratch again on the clutch adjustement and it is improved. Now the problem is better defined. What actually is happening is that the gear shifter is not springing back into position after a gear change. I have to toe it back to center in order to go into the next gear. This seems to be only happening when downshifting from 5--> 4--> 3 --> 2;
N and 1 seem to be a little less of an issue so far. I am driving her very kindly now to see if this degrades or improves. There is a poker run coming up I really want to be on.

So - is there something I am missing here? Could the chain parting have had something to do with this? I was under very low power changing from 1 to 2 when she went - I happened to be looking at the tach and it was at 2,000 under low throttle. Attached is a picture of what the pushrod ended up looking like (2 pieces - and the master that was left)

Thank you for the pointers so far - as you may have guessed by now, I probably shouldn't be doing this kind of work - but as I am retired, my funds are limited, so I do this rather than deplete my retirement funds.

 

[gggGary]

As mentioned the push rod rides in a bushing behind the seal. I am ninety percent certain you need to replace that bushing, the MikesXS sells the bushing, natch.
Clutch pushrod shaft Bushing

Clutch pushrod shaft Bushing - Replaces original bushing inside of pushrod
housing (transmission shaft) and brings clearances back to original. When
stock clearances are too large the pushrod moves to the side and increases
tearing stress on the pushrod seal. (See our catalog for detailed installation
procedure).
Part #01-2020
$4.50 USD Ea
Add to Cart

 

[5twins]

Well, it could be one of those little springs then. It's free to check them, lol. There's also a centering spring on the shift shaft itself, #3 in the drawing below. You can see the ends of it sticking out from behind the shift shaft assembly in the pic above. Maybe that broke.

You may have given quite a jolt to some other components when that chain let go, causing more damage than you thought.

 

[papasmurf]

This is all on the wet side I guess. Perhaps I should learn on the now idle 1978 engine before I venture into the one I am riding. The bushing suggestion also is interesting, but it seems to me that I would notice the clutch pushrod and cable not following the handle by the tension I feel through the handle (does that even make sense the way I worded it?).

I do know that even though I was a couple houses down the street when she went, I heard "Was that noise I heard from the bike?" when I stepped in the house after the fateful ride that evening. Even though I was at low throttle and RPMs when I shifted, there was a lot of energy dissipated when the chain end whacked that pushrod and sidecover!

By the way - how do you guys embed the photos in the posting? I don't see anyway to do that either.

 

[gggGary]

Might have bent the shift shaft? It can be replaced without splitting the cases also right? Do you need to push it out with a dummy shaft so nothing falls out of place while it's out?

 

[papasmurf]

interesting idea - worth investigating. Again maybe a practice session on the 78 may be warranted there.

thank you

 

[5twins]

Yes, practice on the '78 motor, lol. I have a free Photobucket account where I keep all my XS pics. I copy and paste the image code from there into my post and the pics appear like magic.