Transmission problems? '82 GS750T

[jonp84]

Hi,
I have put about 2k miles on my first motorcycle, an '82 GS750T. When I started riding, I'm pretty sure I wasn't very nice to the transmission (I was a bit rough with the clutch as I was learning ). I wasn't too hard on it on purpose, I just wasn't the best clutch operator around. This weekend I took the bike from my house (Seattle, WA) to Oregon. To give context, the 1st to 2nd gear shift has been rough before the trip, but it didn't have any problems. Sometimes it was a bit stiff shifting into first, and that was it.

On the way home form the trip, the bike developed a weird noise. When I started out, there would be weird "clunk.... clunk" noises every second or so that were not rythmic, but seemed to speed up with rpm's. This continued at first to about 3rd gear, but towards the end of the trip it was sneaking all the way up to 5th gear at low rpm's. Once, a 4th to 5th gear shift got stuck between gears and the engine rev'd on the freeway. It sounds as though there is a lose part that is banging around inside the engine somewhere.

I'm fairly mechanically competent, and this forum provides awesome help, so I am not afraid to dive in and try and fix the problem. I just ordered a transmission, because I have seen the 1st to 2nd gear shift get progvessive rougher before this problem happened, so I suspect perhaps a piece of gear broke off and is rattling around in the transmission housing.

Is my diagnosis correct that this is likely a tranny problem? If so, on my way in and out of this area of the bike, is there anything else I should check for wear and possibly replace? The bike has 30k miles and I don't know the maintiance history. Oh, and I checked and the bike had enough oil during the hole trip.


Thanks for your help,
Jon
Owner of a Garaged GS

[psyguy]

it doesnt seem often that these bikes have a transmission problem, especially not after only 30k miles
but i guess if it was abused... thats a different story

the usual suspect for noise is the clutch so you may want to have a look at that

you can have a peek at the trans by dropping the oil sump cover

if you happen to take the cases apart i would first look closely at the shifter mechanism - bent forks or gauged shaft

keep us posted

[jonp84]

That sounds good. A question I have been working with is adjusting the clutch cable tension so that the clutch seems to completely disengage for shifting, but still engage enough to not slip at all. Any pointers?

[psyguy]

not sure what you're asking

[Dizzixx]

I believe he is asking how to adjust the clutch. IE the clutch cable. I have a 77 750 gs and have had a hard time getting my clutch cable adjusted right and was wondering what the procedure was as well. My problem is either the clutch slips because it doesnt engage all the way, or it lulls forward at idle while its in gear with the clutch disengaged.

Dont know if he is having the same problem but it does sound like he wants to know how to adjust the cable.

[jonp84]

Yeah, that was the clutch question I had. I think I will drop the oil sump cover and see if there is anything interesting going on in the transmission. If not, I'll pull the clutch cover and see if I can find the problem. If both those fail. I guess I'll be taking the bike apart this weekend to replace the transmission, and hope that fixes the problem. Thanks for your help!

[psyguy]

you can also try to localize the noise first...
clutch side?
starter clutch side? (this may be your culprit, too)

if you're finding it hard to adjust the clutch, the clutch plates and/or springs may be at their last legs

[jonp84]

I just replaced the clutch plates and springs, but will check them. A clutch problem would be much easier to fix than a transmission problem! I can't tell which side the noise comes from, it sounds like it is coming from the front/bottom of the bike. It only happens if I am in gear, so that limits how well I can locate it.