78 LM1 sticks in neutral

[guzzista]

My recently resurrected from a 20 year slumber LM1  sticks in neutral after a short ride. The gearbox oil was renewed and Moly additive  was added. the refill was done with a measure container. At first it shifts fine and then after a couple miles, nothing,  shift lever moves normally  but no shift as if its stuck between gears . After 5 minutes or less it shifts into first as nothing happened.  Is this a possible stuck detent spring/ ball thing or its time to tear down ?. The bike has approx 15 k miles and from all accounts  it could  be actual mileage accrued. Maybe some of the gearbox  wizards can share some thoughts . Cheers

[Vasco DG]

Sounds like the drum is binding. Perhaps the shims got rusty in the layoff.

Pete

[guzzista]

Thanks, Pete. So in that order it could loosen up..or not . I will get it warmed up and change the gear oil again in the hopes that with movement and lubrication perhaps it will improve, otherwise time to visit the gearbox internals

[Kiwi_Roy]

If the drum was binding wouldn't the lever feel like it was stuck too?

My Eldorado doesn't shift up unless I rock the pedal in the opposite direction first almost like the pawl ratchet is not quite dropping over the tooth. I see the pawl return spring is centered by an eccentric. I tried turning it a little but doesn't seem to do much, what's the procedure on adjusting that?

[guzzista]

Well, it looks like the situation has now become permanent and any shifting, up or down does not get the gearbox out of what  a seems like  false neutral ( the  sound heard when turning the rear wheel by hand indicates that its stuck between  gears . Without any other choices , frame crabbing is now on the agenda to have a look see

[guzzista]

Well, not much time to get the gearbox out this weekend, but, after introducing a screwdriver  into the transmission fill hole and shifting what looks like the sliding sleeve on the output shaft forward , got the shifting back. At this point it looks like that one or more of the nuts on the driven/ lay/  shaft is / are loose . As it stands I haven't been close and personal with a Guzzi gearbox since swapping a broken shift return spring on a 850T I had back in 1983 so any words of wisdom are appreciated. Happy Labor day to all

[Vasco DG]

I believe my shimming instructions with additions by John Noble are still up on Greg Bender's site.

Pete

[guzzista]

Thanks, Pete. Glad to have resources like this when tackling a job. Will report on actual cause of problem when I get it disassembled.

[PeteS]

I will defer to the other Pete's expertise but before taking the transmission out try spraying the clutch spline with WD40. A rusty spline can cause the clutch to drag making shifting hard. Put the bike on the center stand either over gravel or place a catch pan and newspapers under the bell housing. Remove the timing inspection plug, start the motor and spray the heck out of the spline (rear center) while moving the clutch lever. Best securely fasten the spray tip to the can as the starter gear can catch it and drag it into the bell housing. This "fix" usually lasts me about 4-5 months.

Pete

[Vasco DG]

Why in the name of all that's holy would you spray a LUBRICANT into a component that works through friction? And how would you get said lubricant onto the spines hidden in the centre of the assembly?

If the clutch isn't separating properly it will probably be down to a notched hub. The only cure for that is replacement.

Pete

[PeteS]

Pete, it works. WD40 (don't use oil!) will burn off the plates in about ten seconds. I have used on brake disks when storing bikes for a while.  At the very least it will determine if its the splines or something internal as you suggest.

Pete

[Dick]

Well, not much time to get the gearbox out this weekend, but, after introducing a screwdriver  into the transmission fill hole and shifting what looks like the sliding sleeve on the output shaft forward , got the shifting back. At this point it looks like that one or more of the nuts on the driven/ lay/  shaft is / are loose . As it stands I haven't been close and personal with a Guzzi gearbox since swapping a broken shift return spring on a 850T I had back in 1983 so any words of wisdom are appreciated. Happy Labor day to all

Sounds like you may have found the culprit. If the layshaft is moving for and aft with the screwdriver; output bearing shaft nut is loose. Certainly would cause your symptons. Good luck.