5th gear issue

[BA80]

HUH!!! Did you not just repair the gears on one of these bikes? You need to quit smoking your home grown cigarettes and then posting.

5th gear is on the same countershaft as 2nd gear, 3rd, 4th, 1st, and the middle driven gear. Its the dogs on 5th gear that lock into the slots on 2nd gear to put the bike in 2nd gear. This is the mating, or lack there of, that causes the 'ole familiar 2nd gear grind. The main shaft of gears is up above it, that is where the gear that slides for 2nd and 3rd gear is located, the middle shift fork.

5th gear can slide all the way over to the case or in this application bearing attached to the case. When you perform the tech tip gear repair you pull the countershaft bearing out (the one with the three torq head screws), remove the shift fork shaft, and slide the shift fork up off of 5th gear and it slides off the countershaft out the bearing hole. So the only thing keeping the 5th gear from sliding all the way over to the case is the shift fork. If it were bent towards the case side, As it might be if someone tried to hold 5th gear toward second gear while the dogs were slipping out of the slots in second, it could cause the gear to contact the case. And it may well be intermittent.

Now that we add in second gear issues, it seems even more likely. I would agree that dropping the tranny pan and pulling the shift cover is a good first step. Not sure I would go through pulling the engine out just yet. Look at the tech tips for the 2nd gear dremmel repair. It guides you through pulling the countershaft with the engine in the bike. When you pull the countershaft bearing out that is held in with the torq screws you can look and see if it shows signs of the gear rubbing on it. You can also drop the shift fork out and see if it is worn down badly or bent.

I disagree Don. When the 2nd gear dogs are disengaged that 5th gear wheel (on the shaft you are speaking of) and the 5th gear pinion (on the inermediate shaft) are freewheeling until the 2nd gear pinion engages to the 5th gear pinion (moved over by the MIDDLE fork). It doesn't actually have any dogs, the 5th gear wheel is splined inside to accept the teeth of the second gear pinion (again on the intermediate shaft) and that is what actually engages 5th gear.

http://www.powersportsplus.com/parts/search/Yamaha/Motorcycle/1980/XS1100SG/TRANSMISSION/parts.html

[DGXSER]

Greg, I think perhaps we are naming the gears differently. Looking at the diagram you linked to, Item 14 is the countershaft, they call it drive axle.

On it is item 23 2nd gear wheel. It rotates freely from the countershaft, therefore it can rotate without driving the middle driven gears, items 29 and 31, and therefore the middle drive/drive shaft, rear wheel. This also the wheel held in place by the large cicr-clip and the infamous washer that often gets swapped during the dremmel fix, item 24 in the diagram.

Item 26 is the 5th gear wheel, the one you slide out the hole left when you remove the countershaft bearing, shown next to item 26. It is splined to mesh with the splines on the countershaft as shown. When 5th gear turns, it turns the countershaft, and the middle driven gears items 29 and 31, and the rest of the drive train. So 5th gear has the dogs on it, and 2nd gear has the slots that the 5th gear dogs lock into. This is controlled by the left side shift fork, that goes on the 5th gear wheel.

When the bike is shifted into 2nd gear, the 2nd gear wheel is being driven by the 2nd gear pinion and through the 5th gear wheel dogs locked into the slots, the power is transfered through the 5th gear splines to the countershaft, turnign the middle driven gears and the rest of the drive train. When the bike is shifted in to 5th gear, the 5th gear wheel is slid back to interlock with the 5th gear pinion, directly driving the countershaft. If the fork is bent, it could slide 5th gear wheel to far towards the case, or bearing item 26.

If you notice, 1st and 3rd gear wheels also free wheel on the countershaft. 4th gear wheel is splined to the countershaft, it also slides to mate its dogs with the nubs (similar to the slots on 2nd gear) on 1st gear, when the bike is in 1st to transfer power to the countershaft.

[BA80]

I know they use different names. To me the primary shaft is what the main drive chain hooks to, the intermediat is the one in the middle and the secondary is the one you take out to fix 2nd gear.

That's just clouding what I posted. I used the proper names for the gears.

So tell me Don, what gear is the bike in when the 2nd gear pinion is engaged to the 5th gear pinion and spinning the 5th gear wheel?

That illistration is not relative to where it's located in the gear case.

[DGXSER]

Greg,

Looking at the diagram (I have personally not pulled the main shaft out, but I have studied pictures of my transmission and the diagram) the 2nd gear pinion, item 5, which is what the smaller upper middle shift fork moves, never engages with the 5th gear pinion item 8. There are no dogs or slots for them to mesh together with. 2nd gear pinion appears to slide over to interlock with 4th gear pinion (not splined to the main shaft and therefore free wheeling), or disengages from it. Both 2nd and 5th gear pinions appear splined to turn when the main shaft turns, which is the shaft the clutch turns when it is engaged. So there would be no reason for them to interlock. It would appear that 5th gear pinion is stationary,as in it does not slide, and is engaged in the train only when the bike is in 5th gear. When the bike is in 5th gear,the 5th gear wheel slides back via the outer shift fork, to mesh with 5th gear pinion, at that time it turns the countershaft.

So back to the original issue, 5th gear slides via the outer lower shift fork. With a bent shift fork, it could slide to far.

[BA80]

I disagree Don. When the 2nd gear dogs are disengaged that 5th gear wheel (on the shaft you are speaking of) and the 5th gear pinion (on the inermediate shaft) are freewheeling until the 2nd gear pinion engages to the 5th gear pinion (moved over by the MIDDLE fork). It doesn't actually have any dogs, the 5th gear wheel is splined inside to accept the teeth of the second gear pinion (again on the intermediate shaft) and that is what actually engages 5th gear.
http://www.powersportsplus.com/parts...ION/parts.html

Is there some part of this you don't understand?

[DGXSER]

Is there some part of this you don't understand?

Yes...a few...

When the 2nd gear dogs are disengaged

2nd gear has no dogs, 5th gear wheel has the dogs.

5th gear pinion (on the inermediate shaft) are freewheeling until the 2nd gear pinion engages to the 5th gear pinion (moved over by the MIDDLE fork).

5th gear pinion is never free wheeling, it is splined to the main shaft, if one turns they both turn. 2nd gear pinion does not, can not engage 5th gear pinion. Perhaps it was misplaced in your text, but the MIDDLE fork moves 2nd gear pinion, not 5th gear pinion. 2nd gear pinion is also splined to the main shaft, one turns they both turn.

the 5th gear wheel is splined inside to accept the teeth of the second gear pinion (again on the intermediate shaft) and that is what actually engages 5th gear.

The splining inside 5th gear pinion mates to the main shaft, not the teeth of second gear pinion. Other than riding on the main shaft together, 2nd gear pinion and 5th gear pinion have no relationship and do not ever mate, connect, or otherwise interlock.

Best picture I have of the tranny....



The upper shaft, further into the engine, closest to the shift drum, is the main shaft, gear farthest to the right on that shaft is the 5th gear pinion. Note the midle shift fork on the 2nd gear pinion. Also notice there is no way any teeth of the second gear pinion will interlock with 5th gear pinion.

The gears you see on the lower shaft, the countershaft, are right to left, second gear wheel, third gear wheel, 4th gear wheel, 1st gear wheel, and middle driven gear. 5th gear wheel is not installed yet, you can see the bearing hole it slides in through.

[BA80]

OK Don. I quit.

I know how it works.

The 5th gear wheel does have dogs but they engage 2ND gear. Like you said, that's where the second gear slips!!!! Read what YOU post.

The 5TH GEAR pinion IS freewheeling when the 2ND gear pinion is engaged to the 4TH gear pinion or when the second gear pinion is in it's neutral position between the 4th and 5th pinions.



You've been watching the DNC haven't you....

[trbig]

As Greg said. The shift fork sits on the 2nd gear PINION and slides it over to the 5th gear PINION. 2nd gear pinion engages 5th gear pinion by meshing with the INSIDE of the 5th gear as seen by these pics.

[trbig]

Now someone come put these #*$* gears back away for me, will ya?

[BA80]

Thank you Tod, I was fixin' to go make a damn video.

[trbig]

LOL. I shoulda waited a while longer then. Is that damn video different than regular video?

[DGXSER]

Thanks for that picture Todd!! As I said, never had those apart, and was simply judging by the picture I posted as well as the diagram. Never really paid any attention to those gears when I had the tranny apart. I sit corrected.

So 5th gear pinion is NOT splined to the main shaft then? Educational for me and interesting understanding of how the tranny parts function.

What I am not sure I understand though is how that changes the initial point of the discussion, if 5th gear wheel on the countershaft could slide out to the case side and rub if its shift fork were bent.

[BA80]

Well yeah, it may have been a little irregular. SMDH

[BA80]

Thanks for that picture Todd!! As I said, never had those apart, and was simply judging by the picture I posted as well as the diagram. Never really paid any attention to those gears when I had the tranny apart. I sit corrected.

Sounded to me like you were handing out EXPERT advise.






SMDH

[trbig]

Don, the shift fork would would basically have to be gone to let that happen, and even if it did, it would just sit there against the bearing. Nothing there for the gear to grind on. It would nearly HAVE to be rubbing against 2nd for whatever reason to get grinding. And if that circlip is indeed gone between 5th and 2nd, that is letting 2nd move around and is probably contacting 5th. While in 2nd, it would hold the gear over there where it needed to be, and in 1st, 3rd, and 4th, that 5th gear is not spinning as we've just learned. That main 5th gear only spins while in 2nd or 5th and as I said, running in 2nd gear, the 5th gear wheel would be holding 2nd where it needed to be. If the circlip is gone, 5th should be the only time he heard any noise.

And yes... on the 5th PINION gear, it does freewheel on the shaft.