transmission/drive issue

[derek.jent]

I'm just starting on a 79 build. I bought it for $250 bucks. I was told the bike was running when parked a few years ago. The carbs need a little work, but not too bad. I went to spin the back wheel to check compression, etc. and even when in gear it spins like in neutral, but get some crazy clanking noise from the transmission area. My question is, before i go tearing things apart, how possible is it to diagnose/fix transmission or drive problems with the motor in the frame, or is it even possible. From what i can see it doesn't look like it would be easy. But wanted to check with you guys before i go ripping the motor apart. I had been debating on tearing it down and doing a complete rebuild, and maybe doing a few upgrades, so this may be my reason to do so. Just let me know if anyone has been able to do any transmission/drive work with engine together, and on the frame.....or if you have any idea on what this could possibly be.

[tarzan]

Welcome.
I'm in the middle of a transmission repair myself. Yes you can do it with motor in the frame. It is easiest to flip the bike over though, so you can get in there and wrestle the gears out and back in. There is a great write up of the whole process in the repair section.

[BA80]

Don't condemn the transmission until you get it running.

Get it running BEFORE you go off on another tangent. First things first. It really doesn't matter if the transmission works if the engine won't run.

One ting at a time. Do one thing at a time and do it right, and then move on......

[crazy steve]

Don't condemn the transmission until you get it running.

Get it running BEFORE you go off on another tangent. First things first. It really doesn't matter if the transmission works if the engine won't run..

Good advice, with one caveat; I like to pull the oil pan and at least take a look before I get too far into it. If you find large pieces, yeah you might be splitting the cases. But most fixes can be done without complete teardowns or even pulling the motor from the frame.

Generally, transmission issues only manifest themselves when the bike is being ridden. Major breakage is rare except in cases of extreme abuse or neglect.

My recommendation? Before you do anything, pull the cam cover and make sure the cam chain is reasonably tight and the cam timing is right, then make sure the motor will turn over with the starter. Pull the plugs, and connect some cables directly to the starter. If that's a success, check/adjust the valves, then run a compression test. Badly adjusted valves can give low numbers, leading you to think you need top end work. If you get acceptable numbers, the motor will run, at this point it's just fixing things.

[TADracer]

Might want to pull the driveshaft boot back and make sure you don't have a broken U-joint. It is rare a trans fails on these bikes. You can also pull the middle drive and see if there is anything wrong there before you tear into the motor.

[TopCatGr58]

Hey Derek,

Good advice already. Yep, pull the engine to driveshaft/swingarm rubber boot back and then rotate the rear wheel and see if the u-joint spins. A more rare type of damage can be the rear wheel and final drive hub splines get mangled, so the rear wheel could spin but not the driveshaft. OR the final drive to rear wheel splines are ok, but the final drive to driveshaft splines get destroyed because the PO didn't take apart the final drive from the swingarm assembly and clean/relube/grease the driveshaft-final drive splines junction..the zerk fitting does not prperly lubricate that area.

The middle drive is more prone to burning up and locking up when either the hypoid gear oil leaks out, or is drained and accidentally not refilled! When this happens it usually causes a frozen middle drive....often happens while riding which ends up with a locked rear wheel skid at speed!

Next, with the engine not running, it can be difficult to put it into gear even though you may feel/hear the shift lever click....so....spin the rear wheel forward while actuating the shift lever and then see IF the wheel stops. If it does THEN stop, then you know you are now truly in gear. If it still spins easily, then you will need to go deeper. The gears and rear wheel could still spin if there's damage/problems with the clutch. Good Luck.

T.C.

[BA80]

+1 on all that TC said. I thought of the rear wheel spline drive too but as he said, it's pretty rare.

I worked on a 1100 Virago not long ago that had the clutch so far out of adjustment that it did the same thing so the clutch adjustment isn't off the table here either.

[derek.jent]

Thanks for all the thoughts. I do believe the issue may be in the middle drive. I've got the bike on the center stand. I've taken out the plugs, and turned the motor over by hand, so i'm relieved that the motor isn't seized. With it on the center stand i had my wife spin the rear wheel and shifted the gears prior to posting on here. The wheel still spins. I checked the ujoint at the drive shaft at that point, thinking maybe the shaft was not properly connected into the middle drive. The wheel still spins when in gear, and the clanking noise comes from in front of the shaft. I can't really tell if it's middle drive, or transmission thought. I just finished a 81 virago about a month ago, but there's quite a bit less going on with it, than on the xs. The middle drive can be removed with the engine in the frame. It looks like it to an extent. I'm reading through the clymer book for information on all this but only my second bike build, and it seems more complicated at this point. I've got to find a gas tank for it, and get some new plug wires, and finish getting the carbs cleaned up...but am hoping to try and get her running within the next week or so. I was mainly asking if the engine had to be tore down to diagnose because if so i was going to go ahead and replace all the seals, and gaskets whether it really needed it or not....but the engine turns over very easy manually so i think at this point the engine is good. It's very clean from what i can tell, the carbs were just gunked up pretty good. At that point i've got to get pretty much a complete ignition system (key, ignition, starter sylonoid, etc.

[derek.jent]

any likely hood this could be due to something going on with the clutch? Maybe completely out, or stuck in some way shape or form.....but even if that's a possibility would i still be hearing metal on metal clanking sound from the middle drive, or in and around that, area...just brain storming hoping i dont have to take the motor off and apart...

[derek.jent]

found these videos on youtube. The sound this guy has is the same sound i'm hearing..my drive shaft is not moving around like his, but this is the sound...

https://www.youtube.com/watch?v=vo_u9n607jo


https://www.youtube.com/watch?v=QGg-AZkVuSY

[TopCatGr58]

Hey again,

As Greg said, if the throwout rod is adjusted too far IN, then the clutch will not be able to engage, and so even in gear, the rear wheel can spin...will be a little more resistance since it will be turning the gears, but won't turn the engine, and vice versa, spinning the engine while in gear won't spin the rear wheel because the clutch isn't allowing the two to mesh together.

But first, you can just pull the clutch cover adjustment cover off and check the throwout lever and rod adjustment...see the manual for the proper technique.

There are lots of gears and such in the middle drive, and if it's been allowed to get too low on gear hypoid oil, it can be a little noisy.

The clutch basket has a gear edge on the inner portion that drives the oil pump, and due to damage to the shift fork shaft...the "C" clips can come off allowing the the shaft to move/slide sideways, or the oil pump idler gear can come off or loose as well. You can take the engine clutch case cover off without pulling the engine, also can pull the tranny/engine bottom case as well. Yes, the middle drive can be removed also without pulling the engine, but if it's spinning, and you don't see any evidence of gear oil leaking from the u-joint connection, then it's probably good.

T.C.

[derek.jent]

Let me take a step back...i left out one key bit of information from my most recent posts. When i spin the back wheel with it in gear (99.9% sure of that, however can't be sure because the transmission is not engaging the wheel) you can hear the bottom gear, i'm guessing, in the middle drive spin...maybe the noise i'm hearing. I took the cover off the side of the drive, and the gear going into the transmission doesn't spin from what i can see. It will move slightly occasionally if i assist it with my fingers or a wrench while spinning the wheel. So it's like that bottom gear is not catching whatever its supposed to catch that goes into the transmission if that makes sense. I don't see any signs of oil leakage in the drive shaft boot, and all that's tight and not moving from what i can see. I do appreciate all the input on this, and hope i'm not coming off as too much of an FNG...lol.

[cajun31]

It sounds to me like you have diagnosed your problem. From the video and your inspection it does seem that the middle drive is caput. Does it look like it has oil in it? Remove the top fill plug and use something long enough such as a popsicle stick or something to check for fluids. I am guessing that just like in the video you are not going to find any or very little. Fortunately you can either contact member andreashweiss to see if he has a complete middle drive or search Ebay. Your best bet is Andreas as he won't sell you junk and you can never be sure on Ebay purchases.

[derek.jent]

Believe it or not even though it was basically a striped down pays bike it had the original tool kit in the blue yamaha bag with the plastic oil level tester for middle and final drive. Checked it. . Bone dry. ..I figure there's no sense in adding some and trying again. .found one on ebay and ordered it before I saw the suggestion here. ...anybody got a good gas tank with cap key and corresponding ignition their willing to let go of?

[TopCatGr58]

Hey Derek,

Again, contact Andreas Weiss, he's a reputable and fair parts dealer for our bikes. You don't have to get a matching key/ignition switch, you can have it rekeyed or the tank cap rekeyed to match each other by a locksmith. Or...just have 2 keys on your keyfob like I do! IF you have a tank, but need a cap, you can get replacement caps (FOR SPECIALS) from mikesxs.net in new shape...or again contact Andreas.

And that's interesting to hear about the middle drive still spinning with it dry of gear lube! The drain plug for it it back farther than the engine drain plug, but folks sometimes assume that it's part of the engine case, and so after draining, they think it will be filled with the regular oil during the oil/filter change but it's of course not. OR they drain it, and then just forget to fill it, or the drain plug develops a slow leak, and the refill cap allen head gets stripped/reamed out and so they can't get it open to refill??

Hope it fixes your tranny/gear problem!

T.C.