Help with downshifting issues - Anyone know what this is?

[rcoville]

Hi to all:

I'm still wrestling with a down-shifting problem on an '83 GS1100 ES. The problem occurs mainly at highway speed when I need to move down through the gears when reducing speed. There are no issues shifting up through the gears normally ... it's only the downshifting side.

On Friday the dealer near me replaced all components accessible in the gear selector mechanism that do not require splitting the case open. He thought the issue might be with the detente and/or spring but it did not fix the problem.

Yesterday I found a reference in the Haynes manual for this bike. One of the potential fixes reads as follows:

Section 27: Gear selection difficult or impossible

- Gearchange shaft centraliser spring malajusted. This is often characterised by difficulties in changing up or down, but rarely in both directions. Adjust the centraliser anchor bolt as described in Chapter 1.

Chapter 1 covers engine, clutch and gearbox, and I read the entire chapter word for word yesterday. Nowhere in that chapter is there a reference to the centraliser anchor bolt, or how to adjust it. I can find an exploded parts diagram that shows the centraliser spring. It is no. 28 on the attached picture.

Any thoughts on what and where this anchor bolt is? Is it easy to get to?

Thanks for all help.
Rick

[Agemax]

it is screwed into the crankcase, it is not adjustable you just need to make sure the spring is located on the post correctly and the gear change shaft is located centrally on the gear change quadrant that it mates up to when installed

[posplayr]

it is screwed into the crankcase, it is not adjustable you just need to make sure the spring is located on the post correctly and the gear change shaft is located centrally on the gear change quadrant that it mates up to when installed

Is it #29 just below the spring?

[Agemax]

Is it #29 just below the spring?

yes that is the anchor pin for the spring

[rcoville]

Thanks, Agemax.

Another question on that same drawing: Ref. no. 20. Does that screw into the crankcase under the oil pan? I'm assuming to replace the detent plunger and spring I would need to drop the oil pan and it would be accessible?

Thanks
Rick

[trippivot]

downshifting"only" problems are few and some times simple.

did this just start happening - do you remember when this bike actually shifted correctly?

because you are not going to like the reality of down only shifting problems.

shift mech. improperly assembled. in the clutch case

the spring loaded roller on the front shift shaft will present in both directions if it is put on backwards - very easy to do

#1 clutch issue/adjustment (not releasing fully- does it creep at a stop in gear clutch pulled?)

#2 bent shift fork
#3 bent / flexing shift fork shaft
#4 beat up gears mushroomed dogs
#5 circlip on end of shift drum out of groove. walking side to side

drop the pan and have a look - last.

[Agemax]

Thanks, Agemax.

Another question on that same drawing: Ref. no. 20. Does that screw into the crankcase under the oil pan? I'm assuming to replace the detent plunger and spring I would need to drop the oil pan and it would be accessible?

Thanks
Rick

yes you will need to drop the oil pan, then you will gain easy access

[bonanzadave]

Look at the obvious first. Does the shifter arm move on the shaft freely ? Mine was corroded to the point it couldnt overcome the spring tension. Pop that E-clip & washer (40,41) off and make sure the lever (38) moves on the shaft freely.

[rcoville]

trippivot:

This bike was shifting perfectly both up and down the last week of May. It started suddenly one morning when I went for a short drive across town. I went to down-shift coming up to a turn and it would not go. I ended up stopped on the side until I could coax it (by slipping the clutch) to get moving. If I take my time down-shifting (as in stopping in each gear to let it settle in), I can almost drive it normally. The problem lies when you have to stop quickly from a high gear and need to down-shift through the gears quickly. It will get "lost" in the top range and never find it's way down.

The bike has been to the dealer, who pulled out the clutch and replaced everything he could get to WITHOUT splitting open the case. Basically, he replaced no.s 28, 5, 6, 7, 8, 9, 10, 11, 12, and 13. He told me the shift fork was fine and not bent. He also said the clutch was in excellent shape and did not even require replacement of the springs. There is no creep at all. I'm confident the clutch is dis-engaging fully.

Is the circlip you mentioned no. 25, or no. 16? Are these inside the case?

One other thought had occurred to the dealer. No. 19 and it's spring, no. 21. Do you think this detent could be the issue? (As in not indexing properly) I ordered these parts today and I'm going the drop the oil pan when they arrive to inspect and replace them. I need to clean the sump out anyway.

Because of the cost of labor, I have held off splitting open the case until all other solutions have been wrestled down. But if all other solutions don't work, I guess it will have to be done.

[rcoville]

Yep, pulled it off last Saturday to check it out. Everything there works just fine.

[BadBillyB]

trippivot:



One other thought had occurred to the dealer. No. 19 and it's spring, no. 21. Do you think this detent could be the issue? (As in not indexing properly) I ordered these parts today and I'm going the drop the oil pan when they arrive to inspect and replace them. I need to clean the sump out anyway.

Because of the cost of labor, I have held off splitting open the case until all other solutions have been wrestled down. But if all other solutions don't work, I guess it will have to be done.

These parts are only used to hold the shift drum when the bike is in neutral......The part that holds the shift drum in the correct position is part #17 and 18.......No need to split the cases for diagnosis as every thing can be seen with the clutch cover and the oil pan off........Billy

[rcoville]

Hi Billy: Thanks for your input. Are items 17 and 18 up under the oil pan? I thought they were inside the case?

[BadBillyB]

Hi Billy: Thanks for your input. Are items 17 and 18 up under the oil pan? I thought they were inside the case?

Yes they are under the oil pan. Drop the pan and make sure the roller is still intact and the spring is not broken. Dont be surprised if the roller is a little loose as this seems to be normal......Billy

[rcoville]

Thanks very much for your help. I have the gasket on order and will be in there for a peek soon.

Rick